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O'Donnell MJ. Transport of tetraethylammonium by the Malpighian tubules of Trichoplusia ni: Regional specialization and the influence of diet. J Insect Physiol 2023; 146:104505. [PMID: 36935034 DOI: 10.1016/j.jinsphys.2023.104505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/25/2023] [Accepted: 03/14/2023] [Indexed: 06/18/2023]
Abstract
Insect Malpighian tubules (MTs) play a major role in elimination of many potentially toxic compounds, including the organic cation tetraethylammonium (TEA). This paper examines transport of TEA by different segments of the MTs of the cabbage looper, Trichoplusia ni. The results show that the proximal ileac plexus (PIP) region of the MTs plays a dominant role in secretion of the organic cation TEA and that the rate of secretion is altered by feeding; principal cells of the proximal ileac plexus in tubules from larvae with full guts secreted TEA at higher rates than did the same cells in tubules of larvae in which the gut was empty. Michaelis-Menten analysis revealed that TEA secretion by the PIP was saturable and was blocked in a concentration-dependent manner by the organic cation cimetidine. For larvae reared from eggs on TEA-rich diet, higher concentrations of TEA in fluid secreted by the ileac plexus of tubules, and lower concentrations of TEA in the hemolymph, relative to larvae reared on control diet, is consistent with an upregulation of TEA transport in response to higher levels of dietary intake of an exogenous organic cation. The distal and proximal regions of the ileac plexus were also differentiated on the basis of transepithelial and basolateral membrane potentials and the influence of these electrical potentials on organic cation transport are discussed.
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Affiliation(s)
- Michael J O'Donnell
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada.
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Jung S, Kayser EB, Johnson SC, Li L, Worstman HM, Sun GX, Sedensky MM, Morgan PG. Tetraethylammonium chloride reduces anaesthetic-induced neurotoxicity in Caenorhabditis elegans and mice. Br J Anaesth 2022; 128:77-88. [PMID: 34857359 PMCID: PMC8787783 DOI: 10.1016/j.bja.2021.09.036] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/30/2021] [Accepted: 09/15/2021] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND If anaesthetics cause permanent cognitive deficits in some children, the implications are enormous, but the molecular causes of anaesthetic-induced neurotoxicity, and consequently possible therapies, are still debated. Anaesthetic exposure early in development can be neurotoxic in the invertebrate Caenorhabditis elegans causing endoplasmic reticulum (ER) stress and defects in chemotaxis during adulthood. We screened this model organism for compounds that alleviated neurotoxicity, and then tested these candidates for efficacy in mice. METHODS We screened compounds for alleviation of ER stress induction by isoflurane in C. elegans assayed by induction of a green fluorescent protein (GFP) reporter. Drugs that inhibited ER stress were screened for reduction of the anaesthetic-induced chemotaxis defect. Compounds that alleviated both aspects of neurotoxicity were then blindly tested for the ability to inhibit induction of caspase-3 by isoflurane in P7 mice. RESULTS Isoflurane increased ER stress indicated by increased GFP reporter fluorescence (240% increase, P<0.001). Nine compounds reduced induction of ER stress by isoflurane by 90-95% (P<0.001 in all cases). Of these compounds, tetraethylammonium chloride and trehalose also alleviated the isoflurane-induced defect in chemotaxis (trehalose by 44%, P=0.001; tetraethylammonium chloride by 23%, P<0.001). In mouse brain, tetraethylammonium chloride reduced isoflurane-induced caspase staining in the anterior cortical (-54%, P=0.007) and hippocampal regions (-46%, P=0.002). DISCUSSION Tetraethylammonium chloride alleviated isoflurane-induced neurotoxicity in two widely divergent species, raising the likelihood that it may have therapeutic value. In C. elegans, ER stress predicts isoflurane-induced neurotoxicity, but is not its cause.
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Affiliation(s)
- Sangwook Jung
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Ernst-Bernhard Kayser
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Simon C Johnson
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Anesthesiology and Pain Medicine, Seattle, WA, USA; Department of Neurology, University of Washington, Seattle, WA, USA
| | - Li Li
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Anesthesiology and Pain Medicine, Seattle, WA, USA
| | - Hailey M Worstman
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Grace X Sun
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Margaret M Sedensky
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Anesthesiology and Pain Medicine, Seattle, WA, USA
| | - Philip G Morgan
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Anesthesiology and Pain Medicine, Seattle, WA, USA.
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Gaburjáková M, Gaburjáková J, Krejčíová E, Kosnáč D, Kosnáčová H, Nagy Š, Polák Š, Sabo M, Trnka M, Kopáni M. Blocking effect of ferritin on the ryanodine receptor-isoform 2. Arch Biochem Biophys 2021; 712:109031. [PMID: 34534540 DOI: 10.1016/j.abb.2021.109031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 09/08/2021] [Accepted: 09/08/2021] [Indexed: 10/20/2022]
Abstract
Iron, an essential element for most living organism, participates in a wide variety of physiological processes. Disturbance in iron homeostasis has been associated with numerous pathologies, particularly in the heart and brain, which are the most susceptible organs. Under iron-overload conditions, the generation of reactive oxygen species leads to impairment in Ca2+ signaling, fundamentally implicated in cardiac and neuronal physiology. Since iron excess is accompanied by increased expression of iron-storage protein, ferritin, we examined whether ferritin has an effect on the ryanodine receptor - isoform 2 (RYR2), which is one of the major components of Ca2+ signaling. Using the method of planar lipid membranes, we show that ferritin induced an abrupt, permanent blockage of the RYR2 channel. The ferritin effect was strongly voltage dependent and competitively antagonized by cytosolic TEA+, an impermeant RYR2 blocker. Our results collectively indicate that monomeric ferritin highly likely blocks the RYR2 channel by a direct electrostatic interaction within the wider region of the channel permeation pathway.
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Affiliation(s)
- Marta Gaburjáková
- Centre of Biosciences, Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Jana Gaburjáková
- Centre of Biosciences, Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Eva Krejčíová
- Centre of Biosciences, Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Daniel Kosnáč
- Institute of Medical Physics, Biophysics, Informatics and Telemedicine, Faculty of Medicine, Comenius University, Bratislava, Slovakia; Department of Simulation and Virtual Medical Education, Faculty of Medicine, Comenius University, Bratislava, Slovakia
| | - Helena Kosnáčová
- Department of Simulation and Virtual Medical Education, Faculty of Medicine, Comenius University, Bratislava, Slovakia; Slovak Academy of Sciences, Department of Genetics, Cancer Research Institute, Biomedical Research Center, Bratislava, Slovakia
| | - Štefan Nagy
- Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Štefan Polák
- Institute of Histology and Embryology, Faculty of Medicine, Comenius University, Bratislava, Slovakia
| | - Michal Sabo
- Institute of Medical Physics, Biophysics, Informatics and Telemedicine, Faculty of Medicine, Comenius University, Bratislava, Slovakia
| | - Michal Trnka
- Institute of Medical Physics, Biophysics, Informatics and Telemedicine, Faculty of Medicine, Comenius University, Bratislava, Slovakia
| | - Martin Kopáni
- Institute of Medical Physics, Biophysics, Informatics and Telemedicine, Faculty of Medicine, Comenius University, Bratislava, Slovakia.
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Duangjai A, Rukachaisirikul V, Sukpondma Y, Srimaroeng C, Muanprasat C. Antispasmodic Effect of Asperidine B, a Pyrrolidine Derivative, through Inhibition of L-Type Ca 2+ Channel in Rat Ileal Smooth Muscle. Molecules 2021; 26:5492. [PMID: 34576962 PMCID: PMC8470553 DOI: 10.3390/molecules26185492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Revised: 08/29/2021] [Accepted: 09/07/2021] [Indexed: 11/17/2022] Open
Abstract
Antispasmodic agents are used for modulating gastrointestinal motility. Several compounds isolated from terrestrial plants have antispasmodic properties. This study aimed to explore the inhibitory effect of the pyrrolidine derivative, asperidine B, isolated from the soil-derived fungus Aspergillus sclerotiorum PSU-RSPG178, on spasmodic activity. Isolated rat ileum was set up in an organ bath. The contractile responses of asperidine B (0.3 to 30 µM) on potassium chloride and acetylcholine-induced contractions were recorded. To investigate its antispasmodic mechanism, CaCl2, acetylcholine, Nω-nitro-l-arginine methyl ester (l-NAME), nifedipine, methylene blue and tetraethylammonium chloride (TEA) were tested in the absence or in the presence of asperidine B. Cumulative concentrations of asperidine B reduced the ileal contraction by ~37%. The calcium chloride and acetylcholine-induced ileal contraction was suppressed by asperidine B. The effects of asperidine B combined with nifedipine, atropine or TEA were similar to those treated with nifedipine, atropine or TEA, respectively. In contrast, in the presence of l-NAME and methylene blue, the antispasmodic effect of asperidine B was unaltered. These results suggest that the antispasmodic property of asperidine B is probably due to the blockage of the L-type Ca2+ channel and is associated with K+ channels and muscarinic receptor, possibly by affecting non-selective cation channels and/or releasing intracellular calcium.
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Affiliation(s)
- Acharaporn Duangjai
- Unit of Excellence in Research and Product Development of Coffee, Division of Physiology, School of Medical Sciences, University of Phayao, Mueang Phayao, Phayao 56000, Thailand
- Center of Health Outcomes Research and Therapeutic Safety (Cohorts), School of Pharmaceutical Sciences, University of Phayao, Mueang Phayao, Phayao 56000, Thailand
| | - Vatcharin Rukachaisirikul
- Division of Physical Science and Center of Excellence for Innovation in Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90110, Thailand; (V.R.); (Y.S.)
| | - Yaowapa Sukpondma
- Division of Physical Science and Center of Excellence for Innovation in Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90110, Thailand; (V.R.); (Y.S.)
| | - Chutima Srimaroeng
- Department of Physiology, Faculty of Medicine, Chiang Mai University, Mueang Chiang Mai, Chiang Mai 50200, Thailand;
| | - Chatchai Muanprasat
- Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangphli, Samutprakarn 10540, Thailand;
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Rivas-Ramírez P, Reboreda A, Rueda-Ruzafa L, Herrera-Pérez S, Lamas JA. Contribution of KCNQ and TREK Channels to the Resting Membrane Potential in Sympathetic Neurons at Physiological Temperature. Int J Mol Sci 2020; 21:E5796. [PMID: 32806753 PMCID: PMC7461115 DOI: 10.3390/ijms21165796] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 07/31/2020] [Accepted: 08/10/2020] [Indexed: 12/19/2022] Open
Abstract
The ionic mechanisms controlling the resting membrane potential (RMP) in superior cervical ganglion (SCG) neurons have been widely studied and the M-current (IM, KCNQ) is one of the key players. Recently, with the discovery of the presence of functional TREK-2 (TWIK-related K+ channel 2) channels in SCG neurons, another potential main contributor for setting the value of the resting membrane potential has appeared. In the present work, we quantified the contribution of TREK-2 channels to the resting membrane potential at physiological temperature and studied its role in excitability using patch-clamp techniques. In the process we have discovered that TREK-2 channels are sensitive to the classic M-current blockers linopirdine and XE991 (IC50 = 0.310 ± 0.06 µM and 0.044 ± 0.013 µM, respectively). An increase from room temperature (23 °C) to physiological temperature (37 °C) enhanced both IM and TREK-2 currents. Likewise, inhibition of IM by tetraethylammonium (TEA) and TREK-2 current by XE991 depolarized the RMP at room and physiological temperatures. Temperature rise also enhanced adaptation in SCG neurons which was reduced due to TREK-2 and IM inhibition by XE991 application. In summary, TREK-2 and M currents contribute to the resting membrane potential and excitability at room and physiological temperature in the primary culture of mouse SCG neurons.
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Affiliation(s)
- Paula Rivas-Ramírez
- Department of Functional Biology and Health Sciences, Faculty of Biology-CINBIO-IBIV, University of Vigo, Campus Lagoas-Marcosende, 36310 Vigo, Spain; (P.R.-R.); (L.R.-R.); (S.H.-P.)
| | - Antonio Reboreda
- Department of Functional Biology and Health Sciences, Faculty of Biology-CINBIO-IBIV, University of Vigo, Campus Lagoas-Marcosende, 36310 Vigo, Spain; (P.R.-R.); (L.R.-R.); (S.H.-P.)
- Functional Architecture of Memory Department, Leibniz-Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Lola Rueda-Ruzafa
- Department of Functional Biology and Health Sciences, Faculty of Biology-CINBIO-IBIV, University of Vigo, Campus Lagoas-Marcosende, 36310 Vigo, Spain; (P.R.-R.); (L.R.-R.); (S.H.-P.)
| | - Salvador Herrera-Pérez
- Department of Functional Biology and Health Sciences, Faculty of Biology-CINBIO-IBIV, University of Vigo, Campus Lagoas-Marcosende, 36310 Vigo, Spain; (P.R.-R.); (L.R.-R.); (S.H.-P.)
| | - Jose Antonio Lamas
- Department of Functional Biology and Health Sciences, Faculty of Biology-CINBIO-IBIV, University of Vigo, Campus Lagoas-Marcosende, 36310 Vigo, Spain; (P.R.-R.); (L.R.-R.); (S.H.-P.)
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Aksoz E, Sara Y, Onur R. T-type Ca 2+ channel activity increases in rat hippocampal CA1 region during kindling epileptogenesis. Synapse 2020; 74:e22155. [PMID: 32215948 DOI: 10.1002/syn.22155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 03/17/2020] [Accepted: 03/18/2020] [Indexed: 11/07/2022]
Abstract
Epileptogenesis is a dynamical process that involves synaptic plasticity changes such as synaptic reorganization of excitatory and inhibitory systems and axonal sprouting in the hippocampus, which is one of the most studied epileptogenic regions in the brain. However, the early events that trigger these changes are not understood well. We investigated short-term and long-term synaptic plasticity parameters and T-type Ca2+ channel activity changes in the early phase of a rat kindling model. Chronic pentylenetetrazole (PTZ) application was used in order to induce the kindling process in rats. The recordings were obtained from hippocampal slices in the CA1 region at 25th day of PTZ application. Tetraethylammonium was used in order to induce long-term potentiation and T-type Ca2+ channel activity was assessed in the presence of mibefradil. We found that tetraethylammonium-induced long-term potentiation was not prevented by mibefradil in the kindling group in contrast to control group. We also found an increase in paired-pulse ratios in the PTZ-applied group. Our findings indicate an increase in the "T-type Ca2+ channel component of LTP" in the kindling group, which may be an early mechanism in epileptogenesis.
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Affiliation(s)
- Erkan Aksoz
- Faculty of Pharmacy, Department of Pharmacology, Suleyman Demirel University, Isparta, Turkey
| | - Yildirim Sara
- Faculty of Medicine, Department of Pharmacology, Hacettepe University, Ankara, Turkey
| | - Rustu Onur
- Faculty of Medicine, Department of Pharmacology, Near East University, Nicosia, TRNC
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Luo T, Chen Z, Wang F, Yin S, Liu P, Zhang J, Yang Z. Endothelium-Independent Vasodilatory Effects of Isodillapiolglycol Isolated from Ostericum citriodorum. Molecules 2020; 25:molecules25040885. [PMID: 32079290 PMCID: PMC7070945 DOI: 10.3390/molecules25040885] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/09/2020] [Accepted: 02/14/2020] [Indexed: 12/01/2022] Open
Abstract
Ostericum citriodorum is a plant with a native range in China used in herbal medicine for treating angina pectoris. In this study, we investigated the vasodilatory effects of isodillapiolglycol (IDG), which is one of the main ingredients isolated from O. citriodorum ethyl acetate extract, in Sprague–Dawley rat aortic rings, and measured intracellular Ca2+ ([Ca2+]in) using a molecular fluo-3/AM probe. The results show that IDG dose-dependently relaxed endothelium-intact or -denuded aortic rings pre-contracted with noradrenaline (NE) or potassium chloride (KCl), and inhibited CaCl2-induced contraction in high K+ depolarized aortic rings. Tetraethyl ammonium chloride (a Ca2+-activated K+ channel blocker) or verapamil (an L-type Ca2+ channel blocker) significantly reduced the relaxation of IDG in aortic rings pre-contracted with NE. In vascular smooth muscle cells, IDG inhibited the increase in [Ca2+]in stimulated by KCl in Krebs solution; likewise, IDG also attenuated the increase in [Ca2+]in induced by NE or subsequent supplementation of CaCl2. These findings demonstrate that IDG relaxes aortic rings in an endothelium-independent manner by reducing [Ca2+]in, likely through inhibition of the receptor-gated Ca2+ channel and the voltage-dependent Ca2+ channel, and through opening of the Ca2+-activated K+ channel.
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Affiliation(s)
- Tengshuo Luo
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China; (T.L.); (Z.C.)
| | - Zewei Chen
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China; (T.L.); (Z.C.)
| | - Fengyun Wang
- Guangdong Pharmaceutical University, Guangzhou 510006, China;
| | - Shanshan Yin
- HEC Pharm R&D Center, Dongguan 523871, China; (S.Y.); (P.L.)
| | - Pan Liu
- HEC Pharm R&D Center, Dongguan 523871, China; (S.Y.); (P.L.)
| | - Jun Zhang
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China; (T.L.); (Z.C.)
- Correspondence: (J.Z.); (Z.Y.); Tel.: +86-020-39356997 (J.Z.)
| | - Zhonghua Yang
- Medical College of Acupuncture Moxibustion and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
- Correspondence: (J.Z.); (Z.Y.); Tel.: +86-020-39356997 (J.Z.)
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Wu Q, Zhao W, Chen G, Su X, Li R. Relevant effects of Taohong Siwu decoction on isolated rat aortic ring dependent on endothelium nitric oxide-cGMP pathway. Pak J Pharm Sci 2019; 32:261-268. [PMID: 30829202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Using rat thoracic aortic rings to test the relaxing effects of the 95% ethanol extract and aqueous extract of Taohong Siwu decoction (THSW) on endothelium intact or endothelium removed aortic rings. Results showed that the 95% ethanol extract (0.1, 1, 10, 100, 1000 mg•L-1) and aqueous extract (0.1, 1, 10, 100, 1000 mg•L-1) of THSW were able to relax the intact endothelium aortic rings pre-contracted by 10-6 mol•L-1 PE. 10-4 mol•L-1 L-NAME and 10-5 mol•L-1 methylene blue both were able to inhibit the relaxation other than indomethacin. For the endothelium removed aortic rings, potassium channel blocker 3×10-3mol•L-1 tetraethylammonium chloride and 10-5 mol•L-1 glibenclamide had no effect on the relaxation effects caused by the 95% ethanol extract and aqueous extract of THSW. It could be concluded that the 95% ethanol extract and aqueous extract of THSW relax blood vessel by endothelium-dependent way.
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Affiliation(s)
- Qi Wu
- State Key Laboratory of Natural Medicines, Research Department of Pharmacognosy, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Longmian Road, Nanjing, Jiangsu, PR China
| | - Wanlong Zhao
- Shanghai Qingpu Institute for Food and Drug Control, Shanghai, China
| | - Gangling Chen
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Longmian Road, Nanjing, Jiangsu, PR China
| | - Xue Su
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Longmian Road, Nanjing, Jiangsu, PR China
| | - Rong Li
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Longmian Road, Nanjing, Jiangsu, PR China
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Concha G, Bustos D, Zúñiga R, Catalán MA, Zúñiga L. The Insensitivity of TASK-3 K₂P Channels to External Tetraethylammonium (TEA) Partially Depends on the Cap Structure. Int J Mol Sci 2018; 19:ijms19082437. [PMID: 30126179 PMCID: PMC6121469 DOI: 10.3390/ijms19082437] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 08/10/2018] [Accepted: 08/13/2018] [Indexed: 01/12/2023] Open
Abstract
Two-pore domain K⁺ channels (K₂P) display a characteristic extracellular cap structure formed by two M1-P1 linkers, the functional role of which is poorly understood. It has been proposed that the presence of the cap explains the insensitivity of K₂P channels to several K⁺ channel blockers including tetraethylammonium (TEA). We have explored this hypothesis using mutagenesis and functional analysis, followed by molecular simulations. Our results show that the deletion of the cap structure of TASK-3 (TWIK-related acid-sensitive K⁺ channel) generates a TEA-sensitive channel with an IC50 of 11.8 ± 0.4 mM. The enhanced sensitivity to TEA displayed by the cap-less channel is also explained by the presence of an extra tyrosine residue at position 99. These results were corroborated by molecular simulation analysis, which shows an increased stability in the binding of TEA to the cap-less channel when a ring of four tyrosine is present at the external entrance of the permeation pathway. Consistently, Y99A or Y205A single-residue mutants generated in a cap-less channel backbone resulted in TASK-3 channels with low affinity to external TEA.
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Affiliation(s)
- Guierdy Concha
- Centro de Investigaciones Médicas (CIM), Programa de Investigación Asociativa en Cáncer Gástrico (PIA-CG), Escuela de Medicina, Universidad de Talca, Talca 3460000, Chile.
| | - Daniel Bustos
- Centro de Investigaciones Médicas (CIM), Programa de Investigación Asociativa en Cáncer Gástrico (PIA-CG), Escuela de Medicina, Universidad de Talca, Talca 3460000, Chile.
| | - Rafael Zúñiga
- Centro de Investigaciones Médicas (CIM), Programa de Investigación Asociativa en Cáncer Gástrico (PIA-CG), Escuela de Medicina, Universidad de Talca, Talca 3460000, Chile.
| | - Marcelo A Catalán
- Laboratorio de Fisiología Epitelial, Facultad de Ciencias de la Salud, Universidad Arturo Prat, Iquique 1130000, Chile.
| | - Leandro Zúñiga
- Centro de Investigaciones Médicas (CIM), Programa de Investigación Asociativa en Cáncer Gástrico (PIA-CG), Escuela de Medicina, Universidad de Talca, Talca 3460000, Chile.
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Tsai CC, Tey SL, Lee MC, Liu CW, Su YT, Huang SC. Mechanism of resveratrol-induced relaxation of the guinea pig fundus. Phytomedicine 2018; 43:55-59. [PMID: 29747754 DOI: 10.1016/j.phymed.2018.03.061] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 02/10/2018] [Accepted: 03/21/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND Resveratrol is a polyphenolic compound that can be isolated from plants and also is a constituent of red wine. Resveratrol induces relaxation of vascular smooth muscle and may prevent cardiovascular diseases. PURPOSE Impaired gastric accommodation plays an important role in functional dyspepsia and fundic relaxation and is a therapeutic target of functional dyspepsia. Although drugs for fundic relaxation have been developed, these types of drugs are still rare. The purpose of this study was to investigate the relaxant effects of resveratrol in the guinea pig fundus. STUDY DESIGN We studied the relaxant effects of resveratrol in the guinea pig fundus. In addition, we investigated the mechanism of resveratrol-induced relaxation on the guinea pig fundus by using tetraethylammonium (a non-selective potassium channel blocker), apamine (a selective inhibitor of the small conductance calcium-activated potassium channel), iberiotoxin (an inhibitor of large conductance calcium-activated potassium channels), glibenclamide (an ATP-sensitive potassium channel blocker), KT 5720 (a cAMP-dependent protein kinase A inhibitor), KT 5823 (a cGMP-dependent protein kinase G inhibitor), NG-nitro-L-arginine (a competitive inhibitor of nitric oxide synthase), tetrodotoxin (a selective neuronal Na+ channel blocker), ω-conotoxin GVIA (a selective neuronal Ca2+ channel blocker) and G-15 (a G-protein coupled estrogen receptor antagonist). RESULTS The results of this study showed that resveratrol has potent and dose-dependent relaxant effects on the guinea pig fundic muscle. In addition, the results showed that resveratrol-induced relaxation of the guinea pig fundus occurs through nitric oxide and ATP-sensitive potassium channels. CONCLUSION This study provides the first evidence concerning the relaxant effects of resveratrol in the guinea pig fundic muscle strips. Furthermore, resveratrol may be a potential drug to relieve gastrointestinal dyspepsia.
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Affiliation(s)
- Ching-Chung Tsai
- Department of Pediatrics, E-Da Hospital, I-Shou University, Kaohsiung, Taiwan No.1, Yi-Da Road, Yan-Chao, Kaohsiung City, Taiwan, R.O.C.; School of Chinese Medicine for Post Baccalaureate, I-Shou University, Kaohsiung, Taiwan No. 8, Yi-Da Road, Yan-Chao, Kaohsiung City, Taiwan, R.O.C..
| | - Shu-Leei Tey
- Department of Pediatrics, E-Da Hospital, I-Shou University, Kaohsiung, Taiwan No.1, Yi-Da Road, Yan-Chao, Kaohsiung City, Taiwan, R.O.C..
| | - Ming-Che Lee
- Department of General Surgery, Tzu Chi General Hospital and Tzu Chi University, No.707, Section 3, Chung-Yang Road, Hualien, Taiwan, R.O.C..
| | - Ching-Wen Liu
- School of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan No.100, Shih-Chuan 1st Road, Sanmin District, Kaohsiung City, Taiwan, R.O.C..
| | - Yu-Tsun Su
- Department of Pediatrics, E-Da Hospital, I-Shou University, Kaohsiung, Taiwan No.1, Yi-Da Road, Yan-Chao, Kaohsiung City, Taiwan, R.O.C..
| | - Shih-Che Huang
- Department of Internal Medicine, Shosanbetsu Village Clinic, 122-8 Shosanbetsu, Shosanbetsu Village, Tomamae-Gun, Hokkaido 078-4421, Japan.
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11
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Hasegawa Y, Mao W, Saha S, Gunner G, Kolpakova J, Martin GE, Futai K. Luciferase shRNA Presents off-Target Effects on Voltage-Gated Ion Channels in Mouse Hippocampal Pyramidal Neurons. eNeuro 2017; 4:ENEURO.0186-17.2017. [PMID: 29034317 PMCID: PMC5635487 DOI: 10.1523/eneuro.0186-17.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 09/20/2017] [Accepted: 09/25/2017] [Indexed: 12/11/2022] Open
Abstract
RNA interference (RNAi) is a straightforward approach to study gene function from the in vitro cellular level to in vivo animal behavior. Although RNAi-mediated gene knockdown has become essentially routine in neuroscience over the past ten years, off-target effects of short hairpin RNAs (shRNAs) should be considered as the proper choice of control shRNA is critical in order to perform meaningful experiments. Luciferase shRNA (shLuc), targeting firefly luciferase, and scrambled shRNAs (shScrs) have been widely used as controls for vertebrate cell research. However, thorough validation of control shRNAs has not been made to date. Here, we performed thorough physiological and morphological studies against control shRNAs in mouse hippocampal CA1 pyramidal neurons. As expected, all control shRNAs exhibited normal basal synaptic transmission and dendritic morphology. However, to our surprise, shLuc exerted severe off-target effects on voltage-gated ion channel function, while the shScr had no detectable changes. These results indicate that thorough validation of shRNA is imperative and, in the absence of such validation, that shScr is the best available negative control for gene knockdown studies.
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Affiliation(s)
- Yuto Hasegawa
- Brudnick Neuropsychiatric Research Institute and Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01604
| | - Wenjie Mao
- Brudnick Neuropsychiatric Research Institute and Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01604
| | - Sucharita Saha
- Brudnick Neuropsychiatric Research Institute and Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01604
| | - Georgia Gunner
- Brudnick Neuropsychiatric Research Institute and Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01604
| | - Jenya Kolpakova
- Brudnick Neuropsychiatric Research Institute and Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01604
| | - Gilles E Martin
- Brudnick Neuropsychiatric Research Institute and Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01604
| | - Kensuke Futai
- Brudnick Neuropsychiatric Research Institute and Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01604
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12
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Maejima Y, Horita S, Kobayashi D, Aoki M, O'hashi R, Imai R, Sakamoto K, Mori M, Takasu K, Ogawa K, Takenoshita S, Zhao S, Hazama A, Shimomura K. Nesfatin-1 inhibits voltage gated K + channels in pancreatic beta cells. Peptides 2017; 95:10-15. [PMID: 28697955 DOI: 10.1016/j.peptides.2017.07.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 06/26/2017] [Accepted: 07/03/2017] [Indexed: 12/12/2022]
Abstract
The anorexigenic neuropeptide NEFA/nucleobindin 2 (NUCB2)/nesfatin-1-containing neurons are distributed in the brain regions involved in feeding regulation. In spite of the growing knowledge of its physiological functions through extensive studies, its molecular mechanism of reaction, including its receptor, remains unknown. NUCB2/nesfatin-1 is also involved in various peripheral regulations, including glucose homeostasis. In pancreatic beta-cells, NUCB2/nesfatin-1 is reported to enhance glucose-stimulated insulin secretion (GSIS) but its exact mechanism remains unknown. To clarify this mechanism, we measured the effect of nesfatin-1 on the electrical activity of pancreatic beta-cells. Using mouse primary beta cells, we measured changes in the ATP-sensitive K+ (KATP) channel current, the voltage-gated K+ (Kv) channel current, and insulin secretion upon application of nesfatin-1. Nesfatin-1 inhibited the Kv channel, but KATP channel activity was unaffected. Nesfatin-1 enhanced insulin secretion to a same level as Kv channel blocker tetraethylammonium (TEA). The effect was not further enhanced when nesfatin-1 and TEA were applied simultaneously. The inhibition binding assay with [125I]nesfatin-1 in Kv2.1 channels, major contributor of Kv current in beta cell, expressing HEK239 cells indicated the binding of nesfatin-1 on Kv2.1 channel. Because Kv channel inhibition enhances insulin secretion under high glucose conditions, our present data suggest a possible mechanism of nesfatin-1 on enhancing GSIS through regulation of ion channels rather than its unidentified receptor.
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Affiliation(s)
- Yuko Maejima
- Department of Pharmacology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Shoichiro Horita
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Daisuke Kobayashi
- Department of Cellular and Integrative Physiology, Fukushima Medical University, School of Medicine, Fukushima, Japan
| | - Miho Aoki
- Advanced Clinical Research Center, Fukushima Global Medical Science Center, Fukushima Medical University, Japan; Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Rie O'hashi
- Department of Pharmacology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Ryota Imai
- Department of Pharmacology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Kazuho Sakamoto
- Department of Pharmacology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Masatomo Mori
- Jobu Hospital for Respiratory Diseases, Gunma, Japan
| | | | - Kazuma Ogawa
- Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Seiichi Takenoshita
- Advanced Clinical Research Center, Fukushima Global Medical Science Center, Fukushima Medical University, Japan
| | - Songji Zhao
- Advanced Clinical Research Center, Fukushima Global Medical Science Center, Fukushima Medical University, Japan
| | - Akihiro Hazama
- Department of Cellular and Integrative Physiology, Fukushima Medical University, School of Medicine, Fukushima, Japan
| | - Kenju Shimomura
- Department of Pharmacology, Fukushima Medical University School of Medicine, Fukushima, Japan.
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13
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Jenson LJ, Sun B, Bloomquist JR. Voltage-sensitive potassium channels expressed after 20-Hydroxyecdysone treatment of a mosquito cell line. Insect Biochem Mol Biol 2017; 87:75-80. [PMID: 28668511 DOI: 10.1016/j.ibmb.2017.06.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 06/24/2017] [Accepted: 06/26/2017] [Indexed: 06/07/2023]
Abstract
The goal of this research was to express receptors and ion channels in hormone-treated insect cell lines. Treatment of Anopheles gambiae Sua1B cells with 20-hydroxyecdysone showed an inhibition of cell growth over a time course of three days, with no change in cellular morphology. The effect of 20-hydroxyecdysone was enhanced in the presence of the potassium channel blocker 4-aminopyridine, but not tetraethylammonium. Concentration-response curves of 4-aminopyridine in the presence of 42 μM (1 mg/ml) 20-hydroxyecdysone showed similar IC50 values (6-10 μM) across 3 day exposures. Whole cell patch clamp confirmed the expression of delayed-rectifier (Kv2) potassium channels in hormone-supplemented Sua1B cells, whereas untreated Sua1B cells showed no evidence of Kv2 expression. The hormone-induced expression of Kv2 channels occurred in as little as 4 h after treatment, but were not observed after 24 h of exposure to 20-hydroxyecdysone, suggesting they played a role in cell death. The expressed channels had current-voltage relationships diagnostic for the Kv2 subtype, and were inhibited with an IC50 = 13 mM of tetraethylammonium. Overall, these parameters were similar to Anopheles gambiae Kv2 potassium channels expressed in HEK-293 cells. The induced presence of ion channels (and possibly receptors) in these cells has potential utility for high throughput screening and basic neuroscience research.
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Affiliation(s)
- Lacey J Jenson
- Emerging Pathogens Institute, Department of Entomology and Nematology, University of Florida, Gainesville, FL, 32601, USA; Bedoukian Research Inc., 21 Finance Drive, Danbury, CT, 06810, USA
| | - Baonan Sun
- Emerging Pathogens Institute, Department of Entomology and Nematology, University of Florida, Gainesville, FL, 32601, USA
| | - Jeffrey R Bloomquist
- Emerging Pathogens Institute, Department of Entomology and Nematology, University of Florida, Gainesville, FL, 32601, USA.
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14
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Cong B, Chai Y, Wang B, Liu S, Shen J, Wang N, Zhang Q, Huang X. Molecular characterization and functional analysis of four teleostean K + channels in macrophages of sea perch (Lateolabrax japonicas). Fish Shellfish Immunol 2017; 60:426-435. [PMID: 27744058 DOI: 10.1016/j.fsi.2016.09.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 09/15/2016] [Accepted: 09/20/2016] [Indexed: 06/06/2023]
Abstract
Potassium ion channels are one of the most diversely and widely distributed channels, which are involved in all kinds of physiological functions in both excitable and non-excitable cells. The expression of voltage-gated potassium ion (Kv) channels is highly variable according to the state of macrophages activation. Macrophages have an important function in innate immunity against intruding pathogens. They produce a variety of inflammatory and immunoactive molecules that modulate imflammatory responses. Here we show that blockade of K+ channels by non-selective Kv channel inhibitor tetraethylammonium chloride (TEA), and 4-aminopyridine (4-AP) inhibited proinflammatory cytokines expression, cell proliferation, and reactive oxygen species (ROS) production in LPS-stimulated macrophages of Sea perch (Lateolabrax japonicas). Then we isolated four Kv channels genes (spKv1.1, spKv1.2, spKv1.5 and spKv3.1) in LPS-activated fish macrophages. These channels genes were up-regulated after LPS stimulation except spKv3.1, which remained unchanged during the test. The results of this study indicate that Kv channels could be required for modulating the immune function of fish macrophages.
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MESH Headings
- 4-Aminopyridine/pharmacology
- Amino Acid Sequence
- Animals
- Cloning, Molecular
- Cytokines/genetics
- Cytokines/immunology
- Cytokines/metabolism
- DNA, Complementary/genetics
- DNA, Complementary/metabolism
- Fish Proteins/chemistry
- Fish Proteins/genetics
- Fish Proteins/metabolism
- Immunity, Innate/drug effects
- Immunity, Innate/immunology
- Lipopolysaccharides/pharmacology
- Macrophage Activation/drug effects
- Perciformes/genetics
- Perciformes/immunology
- Perciformes/metabolism
- Phylogeny
- Potassium Channel Blockers/pharmacology
- Potassium Channels, Voltage-Gated/chemistry
- Potassium Channels, Voltage-Gated/genetics
- Potassium Channels, Voltage-Gated/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Reactive Oxygen Species/metabolism
- Real-Time Polymerase Chain Reaction/veterinary
- Sequence Alignment/veterinary
- Tetraethylammonium/pharmacology
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Affiliation(s)
- Bailin Cong
- College of Marine Life Sciences, Ocean University of China, Qingdao, Shandong 266003, P.R. China; The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, P.R. China
| | - Yingmei Chai
- Marine College, Shandong University (Weihai), Weihai 264209, P.R. China
| | - Bo Wang
- The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, P.R. China.
| | - Shenghao Liu
- The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, P.R. China
| | - Jihong Shen
- The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, P.R. China
| | - Nengfei Wang
- College of Marine Life Sciences, Ocean University of China, Qingdao, Shandong 266003, P.R. China; The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, P.R. China
| | - Quanqi Zhang
- College of Marine Life Sciences, Ocean University of China, Qingdao, Shandong 266003, P.R. China
| | - Xiaohang Huang
- The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, P.R. China
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15
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Farajnia S, Meijer JH, Michel S. Photoperiod Modulates Fast Delayed Rectifier Potassium Currents in the Mammalian Circadian Clock. ASN Neuro 2016; 8:8/5/1759091416670778. [PMID: 27697884 PMCID: PMC5051630 DOI: 10.1177/1759091416670778] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 08/24/2016] [Indexed: 11/15/2022] Open
Abstract
One feature of the mammalian circadian clock, situated in the suprachiasmatic nucleus (SCN), is its ability to measure day length and thereby contribute to the seasonal adaptation of physiology and behavior. The timing signal from the SCN, namely the 24 hr pattern of electrical activity, is adjusted according to the photoperiod being broader in long days and narrower in short days. Vasoactive intestinal peptide and gamma-aminobutyric acid play a crucial role in intercellular communication within the SCN and contribute to the seasonal changes in phase distribution. However, little is known about the underlying ionic mechanisms of synchronization. The present study was aimed to identify cellular mechanisms involved in seasonal encoding by the SCN. Mice were adapted to long-day (light–dark 16:8) and short-day (light–dark 8:16) photoperiods and membrane properties as well as K+ currents activity of SCN neurons were measured using patch-clamp recordings in acute slices. Remarkably, we found evidence for a photoperiodic effect on the fast delayed rectifier K+ current, that is, the circadian modulation of this ion channel’s activation reversed in long days resulting in 50% higher peak values during the night compared with the unaltered day values. Consistent with fast delayed rectifier enhancement, duration of action potentials during the night was shortened and afterhyperpolarization potentials increased in amplitude and duration. The slow delayed rectifier, transient K+ currents, and membrane excitability were not affected by photoperiod. We conclude that photoperiod can change intrinsic ion channel properties of the SCN neurons, which may influence cellular communication and contribute to photoperiodic phase adjustment.
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Affiliation(s)
- Sahar Farajnia
- Leiden University Medical Center, Leiden, The Netherlands Netherlands Institute for Neuroscience, Amsterdam, The Netherlands
| | | | - Stephan Michel
- Leiden University Medical Center, Leiden, The Netherlands
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16
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Zhang Y, Ding Y, Zhong X, Guo Q, Wang H, Gao J, Bai T, Ren L, Guo Y, Jiao X, Liu Y. Geniposide acutely stimulates insulin secretion in pancreatic β-cells by regulating GLP-1 receptor/cAMP signaling and ion channels. Mol Cell Endocrinol 2016; 430:89-96. [PMID: 27126219 DOI: 10.1016/j.mce.2016.04.020] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/18/2016] [Accepted: 04/23/2016] [Indexed: 12/11/2022]
Abstract
Geniposide, an iridoid glycoside, has antidiabetic effects. The present study aimed to evaluate whether geniposide has direct effects on insulin secretion from rat pancreatic islets. The results demonstrated that geniposide potentiated insulin secretion via activating the glucagon-like-1 receptor (GLP-1R) as well as the adenylyl cyclase (AC)/cAMP signaling pathway. Inhibition of protein kinase A (PKA) suppressed the insulinotropic effect of geniposide. Geniposide also inhibited voltage-dependent potassium (Kv) channels, and this effect could be attenuated by inhibition of GLP-1R or PKA. Current-clamp recording showed that geniposide prolonged action potential duration. These results collectively imply that inhibition of Kv channels is linked to geniposide-potentiated insulin secretion by acting downstream of the GLP-1R/cAMP/PKA signaling pathway. Moreover, activation of Ca(2+) channels by geniposide was observed, indicating that the Ca(2+) channel is also an important player in the geniposide effects. Together, these findings provide new insight into the mechanism underlying geniposide-regulated insulin secretion.
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Affiliation(s)
- Yi Zhang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China; Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, China.
| | - Yaqin Ding
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Xiangqin Zhong
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Qing Guo
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Hui Wang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Jingying Gao
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China; Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, China
| | - Tao Bai
- Department of Endocrinology, The First Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, China; Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, China
| | - Lele Ren
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Yangyan Guo
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Xiangying Jiao
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, China
| | - Yunfeng Liu
- Department of Endocrinology, The First Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, China
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17
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Pelagalli A, Nardelli A, Fontanella R, Zannetti A. Inhibition of AQP1 Hampers Osteosarcoma and Hepatocellular Carcinoma Progression Mediated by Bone Marrow-Derived Mesenchymal Stem Cells. Int J Mol Sci 2016; 17:ijms17071102. [PMID: 27409610 PMCID: PMC4964478 DOI: 10.3390/ijms17071102] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 07/01/2016] [Accepted: 07/05/2016] [Indexed: 12/22/2022] Open
Abstract
The complex cross-talk between tumor cells and their surrounding stromal environment plays a key role in the pathogenesis of cancer. Among several cell types that constitute the tumor stroma, bone marrow-derived mesenchymal stem cells (BM-MSCs) selectively migrate toward the tumor microenvironment and contribute to the active formation of tumor-associated stroma. Therefore, here we elucidate the involvement of BM-MSCs to promote osteosarcoma (OS) and hepatocellular carcinoma (HCC) cells migration and invasion and deepening the role of specific pathways. We analyzed the function of aquaporin 1 (AQP1), a water channel known to promote metastasis and neoangiogenes. AQP1 protein levels were analyzed in OS (U2OS) and HCC (SNU-398) cells exposed to conditioned medium from BM-MSCs. Tumor cell migration and invasion in response to BM-MSC conditioned medium were evaluated through a wound healing assay and Boyden chamber, respectively. The results showed that the AQP1 level was increased in both tumor cell lines after treatment with BM-MSC conditioned medium. Moreover, BM-MSCs-mediated tumor cell migration and invasion were hampered after treatment with AQP1 inhibitor. These data suggest that the recruitment of human BM-MSCs into the tumor microenvironment might cause OS and HCC cell migration and invasion through involvement of AQP1.
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Affiliation(s)
- Alessandra Pelagalli
- Dipartimento di Scienze Biomediche Avanzate, Università degli Studi di Napoli "Federico II", Via Pansini No. 5, 80131 Napoli, Italy.
- Istituto di Biostrutture e Bioimmagini-CNR, Via De Amicis No. 95, 80145 Napoli, Italy.
| | - Anna Nardelli
- Istituto di Biostrutture e Bioimmagini-CNR, Via De Amicis No. 95, 80145 Napoli, Italy.
| | - Raffaela Fontanella
- Istituto di Biostrutture e Bioimmagini-CNR, Via De Amicis No. 95, 80145 Napoli, Italy.
| | - Antonella Zannetti
- Istituto di Biostrutture e Bioimmagini-CNR, Via De Amicis No. 95, 80145 Napoli, Italy.
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18
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Li J, Zhang H, Lei H, Jin M, Yue G, Su Y. Functional identification of a GORK potassium channel from the ancient desert shrub Ammopiptanthus mongolicus (Maxim.) Cheng f. Plant Cell Rep 2016; 35:803-15. [PMID: 26804987 DOI: 10.1007/s00299-015-1922-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2015] [Accepted: 12/09/2015] [Indexed: 05/15/2023]
Abstract
A GORK homologue K(+) channel from the ancient desert shrub Ammopiptanthus mongolicus (Maxim.) Cheng f. shows the functional conservation of the GORK channels among plant species. Guard cell K(+) release through the outward potassium channels eventually enables the closure of stomata which consequently prevents plant water loss from severe transpiration. Early patch-clamp studies with the guard cells have revealed many details of such outward potassium currents. However, genes coding for these potassium-release channels have not been sufficiently characterized from species other than the model plant Arabidopsis thaliana. We report here the functional identification of a GORK (for Gated or Guard cell Outward Rectifying K(+) channels) homologue from the ancient desert shrub Ammopiptanthus mongolicus (Maxim.) Cheng f. AmGORK was primary expressed in shoots, where the transcripts were regulated by stress factors simulated by PEG, NaCl or ABA treatments. Patch-clamp measurements on isolated guard cell protoplasts revealed typical depolarization voltage gated outward K(+) currents sensitive to the extracelluar K(+) concentration and pH, resembling the fundamental properties previously described in other species. Two-electrode voltage-clamp analysis in Xenopus lavies oocytes with AmGORK reconstituted highly similar characteristics as assessed in the guard cells, supporting that the function of AmGORK is consistent with a crucial role in mediating stomatal closure in Ammopiptanthus mongolicus. Furthermore, a single amino acid mutation D297N of AmGORK eventually abolishes both the voltage-gating and its outward rectification and converts the channel into a leak-like channel, indicating strong involvement of this residue in the gating and voltage dependence of AmGORK. Our results obtained from this anciently originated plant support a strong functional conservation of the GORK channels among plant species and maybe also along the progress of revolution.
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Affiliation(s)
- Junlin Li
- College of Forestry, Nanjing Forestry University, Nanjing, 210037, China
- Co-Innovation Center for the Sustainable Forestry in Southern China, Nanjing Forest University, Nanjing, 210037, China
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Huanchao Zhang
- College of Forestry, Nanjing Forestry University, Nanjing, 210037, China
- Co-Innovation Center for the Sustainable Forestry in Southern China, Nanjing Forest University, Nanjing, 210037, China
| | - Han Lei
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Man Jin
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Guangzhen Yue
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Yanhua Su
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.
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19
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Kovács I, Luna C, Quirce S, Mizerska K, Callejo G, Riestra A, Fernández-Sánchez L, Meseguer VM, Cuenca N, Merayo-Lloves J, Acosta MC, Gasull X, Belmonte C, Gallar J. Abnormal activity of corneal cold thermoreceptors underlies the unpleasant sensations in dry eye disease. Pain 2016; 157:399-417. [PMID: 26675826 PMCID: PMC4733818 DOI: 10.1097/j.pain.0000000000000455] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 10/09/2015] [Accepted: 10/28/2015] [Indexed: 12/23/2022]
Abstract
Dry eye disease (DED) affects >10% of the population worldwide, and it provokes an unpleasant sensation of ocular dryness, whose underlying neural mechanisms remain unknown. Removal of the main lachrymal gland in guinea pigs caused long-term reduction of basal tearing accompanied by changes in the architecture and density of subbasal corneal nerves and epithelial terminals. After 4 weeks, ongoing impulse activity and responses to cooling of corneal cold thermoreceptor endings were enhanced. Menthol (200 μM) first excited and then inactivated this augmented spontaneous and cold-evoked activity. Comparatively, corneal polymodal nociceptors of tear-deficient eyes remained silent and exhibited only a mild sensitization to acidic stimulation, whereas mechanonociceptors were not affected. Dryness-induced changes in peripheral cold thermoreceptor responsiveness developed in parallel with a progressive excitability enhancement of corneal cold trigeminal ganglion neurons, primarily due to an increase of sodium currents and a decrease of potassium currents. In corneal polymodal nociceptor neurons, sodium currents were enhanced whereas potassium currents remain unaltered. In healthy humans, exposure of the eye surface to menthol vapors or to cold air currents evoked unpleasant sensations accompanied by increased blinking frequency that we attributed to cold thermoreceptor stimulation. Notably, stimulation with menthol reduced the ongoing background discomfort of patients with DED, conceivably due to use-dependent inactivation of cold thermoreceptors. Together, these data indicate that cold thermoreceptors contribute importantly to the detection and signaling of ocular surface wetness, and develop under chronic eye dryness conditions an injury-evoked neuropathic firing that seems to underlie the unpleasant sensations experienced by patients with DED.
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Affiliation(s)
- Illés Kovács
- Instituto de Neurociencias, Universidad Miguel Hernández–CSIC, San Juan de Alicante, Spain
- Department of Ophthalmology, Semmelweis University, Budapest, Hungary
| | - Carolina Luna
- Instituto de Neurociencias, Universidad Miguel Hernández–CSIC, San Juan de Alicante, Spain
| | - Susana Quirce
- Instituto de Neurociencias, Universidad Miguel Hernández–CSIC, San Juan de Alicante, Spain
| | - Kamila Mizerska
- Instituto de Neurociencias, Universidad Miguel Hernández–CSIC, San Juan de Alicante, Spain
| | - Gerard Callejo
- Laboratory of Neurophysiology, Department of Biomedicine, School of Medicine, University of Barcelona, Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Ana Riestra
- Instituto Universitario Fernández-Vega, Universidad de Oviedo and Fundación de Investigación Oftalmológica, Oviedo, Spain
| | - Laura Fernández-Sánchez
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, San Vicente del Raspeig, Spain
| | - Victor M. Meseguer
- Instituto de Neurociencias, Universidad Miguel Hernández–CSIC, San Juan de Alicante, Spain
| | - Nicolás Cuenca
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, San Vicente del Raspeig, Spain
| | - Jesús Merayo-Lloves
- Instituto Universitario Fernández-Vega, Universidad de Oviedo and Fundación de Investigación Oftalmológica, Oviedo, Spain
| | - M. Carmen Acosta
- Instituto de Neurociencias, Universidad Miguel Hernández–CSIC, San Juan de Alicante, Spain
| | - Xavier Gasull
- Laboratory of Neurophysiology, Department of Biomedicine, School of Medicine, University of Barcelona, Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Carlos Belmonte
- Instituto de Neurociencias, Universidad Miguel Hernández–CSIC, San Juan de Alicante, Spain
- Instituto Universitario Fernández-Vega, Universidad de Oviedo and Fundación de Investigación Oftalmológica, Oviedo, Spain
| | - Juana Gallar
- Instituto de Neurociencias, Universidad Miguel Hernández–CSIC, San Juan de Alicante, Spain
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20
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Touati M, Knipfer T, Visnovitz T, Kameli A, Fricke W. Limitation of Cell Elongation in Barley (Hordeum vulgare L.) Leaves Through Mechanical and Tissue-Hydraulic Properties. Plant Cell Physiol 2015; 56:1364-1373. [PMID: 25907571 DOI: 10.1093/pcp/pcv055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 04/01/2015] [Indexed: 06/04/2023]
Abstract
The aim of the present study was to assess the mechanical and hydraulic limitation of growth in leaf epidermal cells of barley (Hordeum vulgare L.) in response to agents which affect cellular water (mercuric chloride, HgCl(2)) and potassium (cesium chloride, CsCl; tetraethylammonium, TEA) transport, pump activity of plasma membrane H(+)-ATPase and wall acidification (fusicoccin, FC). Cell turgor (P) was measured with the cell pressure probe, and cell osmotic pressure (π) was analyzed through picoliter osmometry of single-cell extracts. A wall extensibility coefficient (M) and tissue hydraulic conductance coefficient (L) were derived using the Lockhart equation. There was a significant positive linear relationship between relative elemental growth rate and P, which fit all treatments, with an overall apparent yield threshold of 0.368 MPa. Differences in growth between treatments could be explained through differences in P. A comparison of L and M showed that growth in all except the FC treatment was co-limited through hydraulic and mechanical properties, though to various extents. This was accompanied by significant (0.17-0.24 MPa) differences in water potential (ΔΨ) between xylem and epidermal cells in the leaf elongation zone. In contrast, FC-treated leaves showed ΔΨ close to zero and a 10-fold increase in L.
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Affiliation(s)
- Mostefa Touati
- Department of Biology, Faculty of Nature and Life Sciences, University Ziane Achour, Djelfa, Algeria
| | - Thorsten Knipfer
- University College Dublin, School of Biology and Environmental Science, Science Centre West, Belfield, Dublin 4, Ireland Present address: Department of Viticulture and Enology, University of California, Davis, CA 95616-5270, USA
| | - Tamás Visnovitz
- University College Dublin, School of Biology and Environmental Science, Science Centre West, Belfield, Dublin 4, Ireland Present address: Research, Chemical Works of Gedeon Richter Plc., H-1103 Budapest, Gyömrői út 19-21, Hungary
| | - Abdelkrim Kameli
- Laboratoire d'Eco-Physiologie Végétale, Département des Sciences Naturelles, Ecole Normale Supérieure de Kouba, 16050, Alger, Algeria
| | - Wieland Fricke
- University College Dublin, School of Biology and Environmental Science, Science Centre West, Belfield, Dublin 4, Ireland
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21
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Gilbert JD, Prentice BM, McLuckey SA. Ion/ion reactions with "onium" reagents: an approach for the gas-phase transfer of organic cations to multiply-charged anions. J Am Soc Mass Spectrom 2015; 26:818-25. [PMID: 25652935 PMCID: PMC4654941 DOI: 10.1007/s13361-015-1077-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 12/27/2014] [Accepted: 01/08/2015] [Indexed: 05/13/2023]
Abstract
The use of ion/ion reactions to effect gas-phase alkylation is demonstrated. Commonly used fixed-charge "onium" cations are well-suited for ion/ion reactions with multiply deprotonated analytes because of their tendency to form long-lived electrostatic complexes. Activation of these complexes results in an SN2 reaction that yields an alkylated anion with the loss of a neutral remnant of the reagent. This alkylation process forms the basis of a general method for alkylation of deprotonated analytes generated via electrospray, and is demonstrated on a variety of anionic sites. SN2 reactions of this nature are demonstrated empirically and characterized using density functional theory (DFT). This method for modification in the gas phase is extended to the transfer of larger and more complex R groups that can be used in later gas-phase synthesis steps. For example, N-cyclohexyl-N'-(2-morpholinoethyl)carbodiimide (CMC) is used to transfer a carbodiimide functionality to a peptide anion containing a carboxylic acid. Subsequent activation yields a selective reaction between the transferred carbodiimide group and a carboxylic acid, suggesting the carbodiimide functionality is retained through the transfer process. Many different R groups are transferable using this method, allowing for new possibilities for charge manipulation and derivatization in the gas phase.
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Affiliation(s)
- Joshua D Gilbert
- Department of Chemistry, Purdue University, West Lafayette, IN, 4907-2084, USA
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22
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Nunes KZ, Nunes DO, Silveira EA, Cruz Pereira CA, Broseghini Filho GB, Vassallo DV, Fioresi M. Chronic lead exposure decreases the vascular reactivity of rat aortas: the role of hydrogen peroxide. PLoS One 2015; 10:e0120965. [PMID: 25807237 PMCID: PMC4373949 DOI: 10.1371/journal.pone.0120965] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 01/27/2015] [Indexed: 01/04/2023] Open
Abstract
We investigated whether exposure to small concentrations of lead alters blood pressure and vascular reactivity. Male Wistar rats were sorted randomly into the following two groups: control (Ct) and treatment with 100 ppm of lead (Pb), which was added to drinking water, for 30 days. Systolic blood pressure (BP) was measured weekly. Following treatment, aortic ring vascular reactivity was assessed. Tissue samples were properly stored for further biochemical investigation. The lead concentration in the blood reached approximately 8 μg/dL. Treatment increased blood pressure and decreased the contractile responses of the aortic rings to phenylephrine (1 nM–100 mM). Following N-nitro-L arginine methyl ester (L-NAME) administration, contractile responses increased in both groups but did not differ significantly between them. Lead effects on Rmax were decreased compared to control subjects following superoxide dismutase (SOD) administration. Catalase, diethyldithiocarbamic acid (DETCA), and apocynin increased the vasoconstrictor response induced by phenylephrine in the aortas of lead-treated rats but did not increase the vasoconstrictor response in the aortas of untreated rats. Tetraethylammonium (TEA) potentiated the vasoconstrictor response induced by phenylephrine in aortic segments in both groups, but these effects were greater in lead-treated rats. The co-incubation of TEA and catalase abolished the vasodilatory effect noted in the lead group. The present study is the first to demonstrate that blood lead concentrations well below the values established by international legislation increased blood pressure and decreased phenylephrine-induced vascular reactivity. The latter effect was associated with oxidative stress, specifically oxidative stress induced via increases in hydrogen peroxide levels and the subsequent effects of hydrogen peroxide on potassium channels.
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Affiliation(s)
- Karolini Zuqui Nunes
- Department of Physiological Sciences, Federal University of Espírito Santo, Vitória, ES, Brazil
- * E-mail:
| | - Dieli Oliveira Nunes
- Department of Physiological Sciences, Federal University of Espírito Santo, Vitória, ES, Brazil
| | - Edna Aparecida Silveira
- Department of Physiological Sciences, Federal University of Espírito Santo, Vitória, ES, Brazil
| | | | | | - Dalton Valentim Vassallo
- Department of Physiological Sciences, Federal University of Espírito Santo, Vitória, ES, Brazil
- Health Science Centre of Vitória—EMESCAM, Vitória, Espírito Santo, Brazil
| | - Mirian Fioresi
- Department of Physiological Sciences, Federal University of Espírito Santo, Vitória, ES, Brazil
- Department of Nursing, Federal University of Espírito Santo, Vitória, ES, Brazil
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23
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Hirst CS, Foong JPP, Stamp LA, Fegan E, Dent S, Cooper EC, Lomax AE, Anderson CR, Bornstein JC, Young HM, McKeown SJ. Ion channel expression in the developing enteric nervous system. PLoS One 2015; 10:e0123436. [PMID: 25798587 PMCID: PMC4370736 DOI: 10.1371/journal.pone.0123436] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 03/03/2015] [Indexed: 12/21/2022] Open
Abstract
The enteric nervous system arises from neural crest-derived cells (ENCCs) that migrate caudally along the embryonic gut. The expression of ion channels by ENCCs in embryonic mice was investigated using a PCR-based array, RT-PCR and immunohistochemistry. Many ion channels, including chloride, calcium, potassium and sodium channels were already expressed by ENCCs at E11.5. There was an increase in the expression of numerous ion channel genes between E11.5 and E14.5, which coincides with ENCC migration and the first extension of neurites by enteric neurons. Previous studies have shown that a variety of ion channels regulates neurite extension and migration of many cell types. Pharmacological inhibition of a range of chloride or calcium channels had no effect on ENCC migration in cultured explants or neuritogenesis in vitro. The non-selective potassium channel inhibitors, TEA and 4-AP, retarded ENCC migration and neuritogenesis, but only at concentrations that also resulted in cell death. In summary, a large range of ion channels is expressed while ENCCs are colonizing the gut, but we found no evidence that ENCC migration or neuritogenesis requires chloride, calcium or potassium channel activity. Many of the ion channels are likely to be involved in the development of electrical excitability of enteric neurons.
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Affiliation(s)
- Caroline S. Hirst
- Department of Anatomy & Neuroscience, University of Melbourne, Parkville, Victoria, Australia
| | - Jaime P. P. Foong
- Department of Anatomy & Neuroscience, University of Melbourne, Parkville, Victoria, Australia
- Department of Physiology, University of Melbourne, Parkville, Victoria, Australia
| | - Lincon A. Stamp
- Department of Anatomy & Neuroscience, University of Melbourne, Parkville, Victoria, Australia
| | - Emily Fegan
- Department of Anatomy & Neuroscience, University of Melbourne, Parkville, Victoria, Australia
| | - Stephan Dent
- Department of Anatomy & Neuroscience, University of Melbourne, Parkville, Victoria, Australia
| | - Edward C. Cooper
- Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Alan E. Lomax
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Colin R. Anderson
- Department of Anatomy & Neuroscience, University of Melbourne, Parkville, Victoria, Australia
| | - Joel C. Bornstein
- Department of Physiology, University of Melbourne, Parkville, Victoria, Australia
| | - Heather M. Young
- Department of Anatomy & Neuroscience, University of Melbourne, Parkville, Victoria, Australia
- * E-mail:
| | - Sonja J. McKeown
- Department of Anatomy & Neuroscience, University of Melbourne, Parkville, Victoria, Australia
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Dias FMV, Ribeiro Júnior RF, Fernandes AA, Fiorim J, Travaglia TCF, Vassallo DV, Stefanon I. Na+K+-ATPase activity and K+ channels differently contribute to vascular relaxation in male and female rats. PLoS One 2014; 9:e106345. [PMID: 25187951 PMCID: PMC4154682 DOI: 10.1371/journal.pone.0106345] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 08/07/2014] [Indexed: 11/19/2022] Open
Abstract
Gender associated differences in vascular reactivity regulation might contribute to the low incidence of cardiovascular disease in women. Cardiovascular protection is suggested to depend on female sex hormones' effects on endothelial function and vascular tone regulation. We tested the hypothesis that potassium (K+) channels and Na+K+-ATPase may be involved in the gender-based vascular reactivity differences. Aortic rings from female and male rats were used to examine the involvement of K+ channels and Na+K+-ATPase in vascular reactivity. Acetylcholine (ACh)-induced relaxation was analyzed in the presence of L-NAME (100 µM) and the following K+ channels blockers: tetraethylammonium (TEA, 2 mM), 4-aminopyridine (4-AP, 5 mM), iberiotoxin (IbTX, 30 nM), apamin (0.5 µM) and charybdotoxin (ChTX, 0.1 µM). The ACh-induced relaxation sensitivity was greater in the female group. After incubation with 4-AP the ACh-dependent relaxation was reduced in both groups. However, the dAUC was greater in males, suggesting that the voltage-dependent K+ channel (Kv) participates more in males. Inhibition of the three types of Ca2+-activated K+ channels induced a greater reduction in Rmax in females than in males. The functional activity of the Na+K+-ATPase was evaluated by KCl-induced relaxation after L-NAME and OUA incubation. OUA reduced K+-induced relaxation in female and male groups, however, it was greater in males, suggesting a greater Na+K+-ATPase functional activity. L-NAME reduced K+-induced relaxation only in the female group, suggesting that nitric oxide (NO) participates more in their functional Na+K+-ATPase activity. These results suggest that the K+ channels involved in the gender-based vascular relaxation differences are the large conductance Ca2+-activated K+ channels (BKCa) in females and Kv in males and in the K+-induced relaxation and the Na+K+-ATPase vascular functional activity is greater in males.
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Affiliation(s)
- Fernanda Moura Vargas Dias
- Universidade Federal do Espírito Santo, Departamento de Ciências Fisiológicas, Vitória, Espírito Santo, Brasil
| | | | - Aurélia Araújo Fernandes
- Universidade Federal do Espírito Santo, Departamento de Ciências Fisiológicas, Vitória, Espírito Santo, Brasil
| | - Jonaina Fiorim
- Universidade Federal do Espírito Santo, Departamento de Ciências Fisiológicas, Vitória, Espírito Santo, Brasil
| | | | - Dalton Valentim Vassallo
- Universidade Federal do Espírito Santo, Departamento de Ciências Fisiológicas, Vitória, Espírito Santo, Brasil
| | - Ivanita Stefanon
- Universidade Federal do Espírito Santo, Departamento de Ciências Fisiológicas, Vitória, Espírito Santo, Brasil
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25
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Prasad M, Zachar V, Fink T, Pennisi CP. Moderate hypoxia influences potassium outward currents in adipose-derived stem cells. PLoS One 2014; 9:e104912. [PMID: 25115627 PMCID: PMC4130641 DOI: 10.1371/journal.pone.0104912] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 07/15/2014] [Indexed: 01/23/2023] Open
Abstract
Moderate hypoxic preconditioning of adipose-derived stem cells (ASCs) enhances properties such as proliferation and secretion of growth factors, representing a valuable strategy to increase the efficiency of cell-based therapies. In a wide variety of cells potassium (K+) channels are key elements involved in the cellular responses to hypoxia, suggesting that ASCs cultured under low oxygen conditions may display altered electrophysiological properties. Here, the effects of moderate hypoxic culture on proliferation, whole-cell currents, and ion channel expression were investigated using human ASCs cultured at 5% and 20% oxygen. Although cell proliferation was greatly enhanced, the dose-dependent growth inhibition by the K+ channel blocker tetraethylammonium (TEA) was not significantly affected by hypoxia. Under both normoxic and hypoxic conditions, ASCs displayed outward K+ currents composed by Ca2+-activated, delayed rectifier, and transient components. Hypoxic culture reduced the slope of the current-voltage curves and caused a negative shift in the voltage activation threshold of the whole-cell currents. However, the TEA-mediated shift of voltage activation threshold was not affected by hypoxia. Semiquantitative real-time RT-PCR revealed that expression of genes encoding for various ion channels subunits related to oxygen sensing and proliferation remained unchanged after hypoxic culture. In conclusion, outward currents are influenced by moderate hypoxia in ASCs through a mechanism that is not likely the result of modulation of TEA-sensitive K+ channels.
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Affiliation(s)
- Mayuri Prasad
- Laboratory for Stem Cell Research, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Vladimir Zachar
- Laboratory for Stem Cell Research, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Trine Fink
- Laboratory for Stem Cell Research, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Cristian Pablo Pennisi
- Laboratory for Stem Cell Research, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
- * E-mail:
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26
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Zhao DJ, Wang ZY, Huang L, Jia YP, Leng JQ. Spatio-temporal mapping of variation potentials in leaves of Helianthus annuus L. seedlings in situ using multi-electrode array. Sci Rep 2014; 4:5435. [PMID: 24961469 PMCID: PMC4069705 DOI: 10.1038/srep05435] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 06/05/2014] [Indexed: 12/30/2022] Open
Abstract
Damaging thermal stimuli trigger long-lasting variation potentials (VPs) in higher plants. Owing to limitations in conventional plant electrophysiological recording techniques, recorded signals are composed of signals originating from all of the cells that are connected to an electrode. This limitation does not enable detailed spatio-temporal distributions of transmission and electrical activities in plants to be visualised. Multi-electrode array (MEA) enables the recording and imaging of dynamic spatio-temporal electrical activities in higher plants. Here, we used an 8 × 8 MEA with a polar distance of 450 μm to measure electrical activities from numerous cells simultaneously. The mapping of the data that were recorded from the MEA revealed the transfer mode of the thermally induced VPs in the leaves of Helianthus annuus L. seedlings in situ. These results suggest that MEA can enable recordings with high spatio-temporal resolution that facilitate the determination of the bioelectrical response mode of higher plants under stress.
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Affiliation(s)
- Dong-Jie Zhao
- College of Information and Electrical Engineering, China Agricultural University, Beijing 100083, China
| | - Zhong-Yi Wang
- College of Information and Electrical Engineering, China Agricultural University, Beijing 100083, China
| | - Lan Huang
- College of Information and Electrical Engineering, China Agricultural University, Beijing 100083, China
| | | | - John Q. Leng
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520, USA
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27
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Liu DH, Huang X, Guo X, Meng XM, Wu YS, Lu HL, Zhang CM, Kim YC, Xu WX. Voltage dependent potassium channel remodeling in murine intestinal smooth muscle hypertrophy induced by partial obstruction. PLoS One 2014; 9:e86109. [PMID: 24516526 PMCID: PMC3916336 DOI: 10.1371/journal.pone.0086109] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 12/05/2013] [Indexed: 11/18/2022] Open
Abstract
Partial obstruction of the small intestine causes obvious hypertrophy of smooth muscle cells and motility disorder in the bowel proximate to the obstruction. To identify electric remodeling of hypertrophic smooth muscles in partially obstructed murine small intestine, the patch-clamp and intracellular microelectrode recording methods were used to identify the possible electric remodeling and Western blot, immunofluorescence and immunoprecipitation were utilized to examine the channel protein expression and phosphorylation level changes in this research. After 14 days of obstruction, partial obstruction caused obvious smooth muscle hypertrophy in the proximally located intestine. The slow waves of intestinal smooth muscles in the dilated region were significantly suppressed, their amplitude and frequency were reduced, whilst the resting membrane potentials were depolarized compared with normal and sham animals. The current density of voltage dependent potassium channel (KV) was significantly decreased in the hypertrophic smooth muscle cells and the voltage sensitivity of KV activation was altered. The sensitivity of KV currents (IKV) to TEA, a nonselective potassium channel blocker, increased significantly, but the sensitivity of IKv to 4-AP, a KV blocker, stays the same. The protein levels of KV4.3 and KV2.2 were up-regulated in the hypertrophic smooth muscle cell membrane. The serine and threonine phosphorylation levels of KV4.3 and KV2.2 were significantly increased in the hypertrophic smooth muscle cells. Thus this study represents the first identification of KV channel remodeling in murine small intestinal smooth muscle hypertrophy induced by partial obstruction. The enhanced phosphorylations of KV4.3 and KV2.2 may be involved in this process.
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Affiliation(s)
- Dong-Hai Liu
- Department of Physiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Xu Huang
- Department of Physiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Xin Guo
- Department of Physiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Xiang-Min Meng
- Department of Physiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yi-Song Wu
- Department of Physiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Hong-Li Lu
- Department of Physiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Chun-Mei Zhang
- Department of Physiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Young-chul Kim
- Department of Physiology, Chungbuk National University College of Medicine, Cheongju, Chungbuk, Republic of Korea
| | - Wen-Xie Xu
- Department of Physiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
- * E-mail:
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28
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Kerckhove N, Mallet C, François A, Boudes M, Chemin J, Voets T, Bourinet E, Alloui A, Eschalier A. Ca(v)3.2 calcium channels: the key protagonist in the supraspinal effect of paracetamol. Pain 2014; 155:764-772. [PMID: 24447516 DOI: 10.1016/j.pain.2014.01.015] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 12/25/2013] [Accepted: 01/14/2014] [Indexed: 12/20/2022]
Abstract
To exert its analgesic action, paracetamol requires complex metabolism to produce a brain-specific lipoamino acid compound, AM404, which targets central transient receptor potential vanilloid receptors (TRPV1). Lipoamino acids are also known to induce analgesia through T-type calcium-channel inhibition (Ca(v)3.2). In this study we show that the antinociceptive effect of paracetamol in mice is lost when supraspinal Ca(v)3.2 channels are inhibited. Therefore, we hypothesized a relationship between supraspinal Ca(v)3.2 and TRPV1, via AM404, which mediates the analgesic effect of paracetamol. AM404 is able to activate TRPV1 and weakly inhibits Ca(v)3.2. Interestingly, activation of TRPV1 induces a strong inhibition of Ca(v)3.2 current. Supporting this, intracerebroventricular administration of AM404 or capsaicin produces antinociception that is lost in Ca(v)3.2(-/-) mice. Our study, for the first time, (1) provides a molecular mechanism for the supraspinal antinociceptive effect of paracetamol; (2) identifies the relationship between TRPV1 and the Ca(v)3.2 channel; and (3) suggests supraspinal Ca(v)3.2 inhibition as a potential pharmacological strategy to alleviate pain.
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Affiliation(s)
- Nicolas Kerckhove
- Clermont Université, Université d'Auvergne, Pharmacologie Fondamentale et Clinique de la Douleur, 63000 Clermont-Ferrand, France INSERM, U 1107, Neuro-Dol, 63000 Clermont-Ferrand, France CHU Clermont-Ferrand, Service de Pharmacologie, 63003 Clermont-Ferrand, France Laboratories of Excellence, Ion Channel Science and Therapeutics, Institut de Génomique Fonctionnelle, 141 rue de la Cardonille, 34094 Montpellier, France CNRS UMR5203, Montpellier, France INSERM, U661, Montpellier, France IFR3 Universités Montpellier I & II, Montpellier, France Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
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Abstract
Regulation of stomatal aperture is crucial in terrestrial plants for controlling water loss and gaseous exchange with environment. While much is known of signaling for stomatal opening induced by blue light and the role of hormones, little is known about the regulation of stomatal closing in darkness. The present study was aimed to verify their role in stomatal regulation in darkness. Epidermal peelings from the leaves of Commelina benghalensis were incubated in a defined medium in darkness for 1 h followed by a 1 h incubation in different test solutions [H2O2, propyl gallate, ethrel (ethylene), AgNO3, sodium orthovanadate, tetraethyl ammonium chloride, CaCl2, LaCl3, separately and in combination] before stomatal apertures were measured under the microscope. In the dark stomata remained closed under treatments with ethylene and propyl gallate but opened widely in the presence of H2O2 and AgNO3. The opening effect was largely unaffected by supplementing the treatment with Na-vanadate (PM H+ ATPase inhibitor) and tetraethyl ammonium chloride (K(+)-channel inhibitor) except that opening was significantly inhibited by the latter in presence of H2O2. On the other hand, H2O2 could not override the closing effect of ethylene at any concentrations while a marginal opening of stomata was found when Ag NO3 treatment was given together with propyl gallate. CaCl2 treatment opened stomata in the darkness while LaCl3 maintained stomata closed. A combination of LaCl3 and propyl gallate strongly promoted stomatal opening. A probable action of ethylene in closing stomata of Commelina benghalensis in dark has been proposed.
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Affiliation(s)
- R K Kar
- Plant Physiology and Biochemistry Laboratory, Department of Botany, Visva-Bharati University, Santiniketan-731 235, West Bengal, India
| | - N Parvin
- Department of Botany, Biology-1, Biocentre, Ludwig Maximillians, University of Munich, 82152 Martinsried, Germany
| | - D Laha
- Centre for Plant Molecular Biology, Eberhard Karls, University of Tuebingen, Auf der Morgenstelle 1, 72076 Tuebingen, Germany
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30
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Novakovic R, Ilic B, Beleslin-Cokic B, Radunovic N, Heinle H, Scepanovic R, Gojkovic-Bukarica L. The effect of resveratrol on contractility of non-pregnant rat uterus: the contribution of K(+) channels. J Physiol Pharmacol 2013; 64:795-805. [PMID: 24388895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 11/13/2013] [Indexed: 06/03/2023]
Abstract
This study was aimed to evaluate resveratrol (1-100 μM) effect on the spontaneous rhythmic contractions (SRC), oxytocin-induced (0.2 nM, POxC) phasic and tonic (20 nM, TOxC) contractions of isolated rat uterus. The SRC and POxC were more sensitive to resveratrol than TOxC (pD2 values: 4.53 and 4.66 versus 4.06). Different blockers of K(+) channels (glibenclamide, tetraethylamonium, iberiotoxin, 4-aminopyridine) antagonized the response to resveratrol on the SRC and phasic contractions, but did not antagonize the effect of resveratrol on the TOxC. In order to compare the relaxant activities of resveratrol on the TOxC with that of potassium channel openers, a separate experiments with NS 1619, a highly specific big Ca(2+)-sensitive K(+) (BKCa) channels opener and pinacidil, a predominant opener of ATP-sensitive K(+) (KATP) channels were done. NS 1619 (10-100 μM) and pinacidil (10-100 μM) produced more potent inhibition of TOxC than resveratrol (pD2 values were 6.00 and 5.29). Iberiotoxin, a highly selective BKCa channels blocker, antagonized the response to NS 1619 and glibenclamide, a highly selective KATP channels blocker, antagonized the response to pinacidil on the TOxC. To test K(+)- and extracellular Ca(2+)- independent mechanism(s) of resveratrol on TOxC, a K(+)-rich, Ca(2+)-free solution was used. Under this condition, only high concentrations (≥30 μM) of resveratrol inhibited TOxC. Western blots analysis confirmed expression of Kir6.1, Kir6.2, KCa1.1, Kv2.1 and Kv4.2. channel proteins in myometrium. Thus, the effect of resveratrol is dependent on the types of contractions. The inhibitory response of resveratrol on the SRC and phasic contractions involves different myometrial K(+)- channels. When applied in high concentrations, resveratrol has an additional K(+)- channels independent mechanism(s) of action. As the effects of NS 1619, pinacidil and resveratrol on the TOxC are different, we can conclud that resveratrol does not behave as a classical potassium channel opener.
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Affiliation(s)
- R Novakovic
- Institute of Pharmacology, Clinical Pharmacology and Toxicology, Medical Faculty, University of Belgrade, Belgrade, Serbia.
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Zhong LR, Estes S, Artinian L, Rehder V. Nitric oxide regulates neuronal activity via calcium-activated potassium channels. PLoS One 2013; 8:e78727. [PMID: 24236040 PMCID: PMC3827272 DOI: 10.1371/journal.pone.0078727] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 09/22/2013] [Indexed: 12/13/2022] Open
Abstract
Nitric oxide (NO) is an unconventional membrane-permeable messenger molecule that has been shown to play various roles in the nervous system. How NO modulates ion channels to affect neuronal functions is not well understood. In gastropods, NO has been implicated in regulating the feeding motor program. The buccal motoneuron, B19, of the freshwater pond snail Helisoma trivolvis is active during the hyper-retraction phase of the feeding motor program and is located in the vicinity of NO-producing neurons in the buccal ganglion. Here, we asked whether B19 neurons might serve as direct targets of NO signaling. Previous work established NO as a key regulator of growth cone motility and neuronal excitability in another buccal neuron involved in feeding, the B5 neuron. This raised the question whether NO might modulate the electrical activity and neuronal excitability of B19 neurons as well, and if so whether NO acted on the same or a different set of ion channels in both neurons. To study specific responses of NO on B19 neurons and to eliminate indirect effects contributed by other cells, the majority of experiments were performed on single cultured B19 neurons. Addition of NO donors caused a prolonged depolarization of the membrane potential and an increase in neuronal excitability. The effects of NO could mainly be attributed to the inhibition of two types of calcium-activated potassium channels, apamin-sensitive and iberiotoxin-sensitive potassium channels. NO was found to also cause a depolarization in B19 neurons in situ, but only after NO synthase activity in buccal ganglia had been blocked. The results suggest that NO acts as a critical modulator of neuronal excitability in B19 neurons, and that calcium-activated potassium channels may serve as a common target of NO in neurons.
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Affiliation(s)
- Lei Ray Zhong
- Biology Department, Georgia State University, Atlanta, Georgia, United States of America
| | - Stephen Estes
- Biology Department, Georgia State University, Atlanta, Georgia, United States of America
| | - Liana Artinian
- Biology Department, Georgia State University, Atlanta, Georgia, United States of America
| | - Vincent Rehder
- Biology Department, Georgia State University, Atlanta, Georgia, United States of America
- * E-mail:
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Robbins J, Passmore GM, Abogadie FC, Reilly JM, Brown DA. Effects of KCNQ2 gene truncation on M-type Kv7 potassium currents. PLoS One 2013; 8:e71809. [PMID: 23977150 PMCID: PMC3748097 DOI: 10.1371/journal.pone.0071809] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 07/02/2013] [Indexed: 11/23/2022] Open
Abstract
The KCNQ2 gene product, Kv7.2, is a subunit of the M-channel, a low-threshold voltage-gated K+ channel that regulates mammalian and human neuronal excitability. Spontaneous mutations one of the KCNQ2 genes cause disorders of neural excitability such as Benign Familial Neonatal Seizures. However there appear to be no reports in which both human KCNQ2 genes are mutated. We therefore asked what happens to M-channel function when both KCNQ2 genes are disrupted. We addressed this using sympathetic neurons isolated from mice in which the KCNQ2 gene was truncated at a position corresponding to the second transmembrane domain of the Kv7.2 protein. Since homozygote KCNQ2−/− mice die postnatally, experiments were largely restricted to neurons from late embryos. Quantitative PCR revealed an absence of KCNQ2 mRNA in ganglia from KCNQ2−/− embryos but 100–120% increase of KCNQ3 and KCNQ5 mRNAs; KCNQ2+/− ganglia showed ∼30% less KCNQ2 mRNA than wild-type (+/+) ganglia but 40–50% more KCNQ3 and KCNQ5 mRNA. Neurons from KCNQ2−/− embryos showed a complete absence of M-current, even after applying the Kv7 channel enhancer, retigabine. Neurons from heterozygote KCNQ2+/− embryos had ∼60% reduced M-current. In contrast, M-currents in neurons from adult KCNQ2+/− mice were no smaller than those in neurons from wild-type mice. Measurements of tetraethylammonium block did not indicate an increased expression of Kv7.5-containing subunits, implying a compensatory increase in Kv7.2 expression from the remaining KCNQ2 gene. We conclude that mouse embryonic M-channels have an absolute requirement for Kv7.2 subunits for functionality, that the reduced M-channel activity in heterozygote KCNQ2+/− mouse embryos results primarily from a gene-dosage effect, and that there is a compensatory increase in Kv7.2 expression in adult mice.
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Affiliation(s)
- Jon Robbins
- Wolfson Centre for Age Related Disease, King's College London, London, United Kingdom
- * E-mail:
| | - Gayle M. Passmore
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Fe C. Abogadie
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
- Health Innovations Research Institute, Royal Melbourne Institute of Technology University, Victoria, Australia
| | - Joanne M. Reilly
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - David A. Brown
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
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Tricarico D, Mele A, Calzolaro S, Cannone G, Camerino GM, Dinardo MM, Latorre R, Conte Camerino D. Emerging role of calcium-activated potassium channel in the regulation of cell viability following potassium ions challenge in HEK293 cells and pharmacological modulation. PLoS One 2013; 8:e69551. [PMID: 23874973 PMCID: PMC3712936 DOI: 10.1371/journal.pone.0069551] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 06/10/2013] [Indexed: 11/18/2022] Open
Abstract
Emerging evidences suggest that Ca2+activated-K+-(BK) channel is involved in the regulation of cell viability. The changes of the cell viability observed under hyperkalemia (15 mEq/L) or hypokalemia (0.55 mEq/L) conditions were investigated in HEK293 cells expressing the hslo subunit (hslo-HEK293) in the presence or absence of BK channel modulators. The BK channel openers(10-11-10-3M) were: acetazolamide(ACTZ), Dichlorphenamide(DCP), methazolamide(MTZ), bendroflumethiazide(BFT), ethoxzolamide(ETX), hydrochlorthiazide(HCT), quercetin(QUERC), resveratrol(RESV) and NS1619; and the BK channel blockers(2x10-7M-5x10-3M) were: tetraethylammonium(TEA), iberiotoxin(IbTx) and charybdotoxin(ChTX). Experiments on cell viability and channel currents were performed using cell counting kit-8 and patch-clamp techniques, respectively. Hslo whole-cell current was potentiated by BK channel openers with different potency and efficacy in hslo-HEK293. The efficacy ranking of the openers at -60 mV(Vm) was BFT> ACTZ >DCP ≥RESV≥ ETX> NS1619> MTZ≥ QUERC; HCT was not effective. Cell viability after 24 h of incubation under hyperkalemia was enhanced by 82+6% and 33+7% in hslo-HEK293 cells and HEK293 cells, respectively. IbTx, ChTX and TEA enhanced cell viability in hslo-HEK293. BK openers prevented the enhancement of the cell viability induced by hyperkalemia or IbTx in hslo-HEK293 showing an efficacy which was comparable with that observed as BK openers. BK channel modulators failed to affect cell currents and viability under hyperkalemia conditions in the absence of hslo subunit. In contrast, under hypokalemia cell viability was reduced by -22+4% and -23+6% in hslo-HEK293 and HEK293 cells, respectively; the BK channel modulators failed to affect this parameter in these cells. In conclusion, BK channel regulates cell viability under hyperkalemia but not hypokalemia conditions. BFT and ACTZ were the most potent drugs either in activating the BK current and in preventing the cell proliferation induced by hyperkalemia. These findings may have relevance in disorders associated with abnormal K+ ion homeostasis including periodic paralysis and myotonia.
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Renzel R, Sadek AR, Chang CH, Gray WP, Seifert G, Steinhäuser C. Polarized distribution of AMPA, but not GABAA , receptors in radial glia-like cells of the adult dentate gyrus. Glia 2013; 61:1146-54. [PMID: 23633386 DOI: 10.1002/glia.22505] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 03/12/2013] [Indexed: 11/07/2022]
Abstract
Glial fibrillary acidic protein (GFAP)-positive astrocytes with radial processes [radial glia (RG)-like cells] in the postnatal dentate gyrus share many of the characteristics of embryonic radial glia and appear to act as precursor cells for adult dentate neurogenesis, a process important for pattern separation and hippocampus-dependent learning. Although much work has delineated the mechanisms underlying activity-neurogenesis coupling via gamma-amino butyric acid (GABA)ergic neurotransmission on GFAP-negative transient-amplifying cells and neuroblasts, little is known regarding the effects of neurotransmitters on RG-like cells. Conflicting evidence exists for both GABA and glutamate receptors on these cells. Here, using GFAP reporter mice, we show that the somatic membrane of RG-like cells carries GABAA receptors and glutamate transporters but not ionotropic glutamate receptors, whereas 2-amino-3-(hydroxyl-5-methylisoxazole-4-yl) propionic acid (AMPA) and GABAA receptors are expressed on the processes of these cells. Almost all RG-like cells expressed the GluA2 subunit, which restricts the Ca(2+) permeability of AMPA receptors. The glial GABAA receptors mainly comprised α2/α4, β1, and γ1/γ3. The selective presence of AMPA receptors on the radial processes may be important for sensing and responding to local activity-driven glutamate release and supports the concept that RG-like astrocytes are composed of functional and structural domains.
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Affiliation(s)
- Roland Renzel
- Institute of Cellular Neurosciences, University of Bonn, Bonn, Germany
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Li S, Maude-Griffin R, Pullan AJ, Chen JDZ. Gastric emptying and Ca(2+) and K(+) channels of circular smooth muscle cells in diet-induced obese prone and resistant rats. Obesity (Silver Spring) 2013; 21:326-35. [PMID: 23404843 DOI: 10.1002/oby.20021] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2012] [Accepted: 06/18/2012] [Indexed: 12/27/2022]
Abstract
OBJECTIVE Accelerated gastric emptying that precipitates hunger and frequent eating could be a potential factor in the development of obesity. The aim of this study was to study gastric emptying in diet-induced obese-prone (DIO-P) and DIO-resistant (DIO-R) rats and explore possible differences in electrical properties of calcium (Ca(2+) ) and potassium (K(+) ) channels of antral circular smooth muscle cells (SMCs). DESIGN AND METHODS Whole-cell patch-clamp technique was used to measure Ca(2+) and K(+) currents in single SMCs. Gastric emptying was evaluated 90 min after the ingestion of a solid meal. RESULTS Solid gastric emptying in the DIO-P rats was significantly faster compared with that in the DIO-R rats. The peak amplitude of L-type Ca(2+) current (IBa,L ) at 10 mV in DIO-P rats was greater than that in DIO-R rats without alternation of the current-voltage curve and voltage-dependent activation and inactivation. The half-maximal inactivation voltage of transient outward K(+) current (IKto ) was more depolarized (∼4 mV) in DIO-P rats compared with that in DIO-R rats. No difference was found in the current density or recovery kinetics of IKto between two groups. The current density of delayed rectifier K(+) current (IKdr ), which was sensitive to tetraethylammonium chloride but not 4-aminopyridine, was lower in DIO-P rats than that in DIO-R rats. CONCLUSION The accelerated gastric emptying in DIO-P rats might be attributed to a higher density of IBa,L , depolarizing shift of inactivation curve of IKto and lower density of IKdr observed in the antral SMCs of DIO-P rats.
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Affiliation(s)
- Shiying Li
- Veterans Research and Education Foundation, VA Medical Center, Oklahoma, Oklahoma, USA
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Danylovych IV, Chunikhin OI, Danylovych HV. [Investigation of the changes in uterine myocytes size depending on contractile activity modulators by photon correlation spectroscopy]. Fiziol Zh (1994) 2013; 59:32-39. [PMID: 23713348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
By using photon correlation spectroscopy the effect of contractile activity modulators of smooth muscle to the size (diameter) of rats uterine muscle cells was investigated. Cells were studied by using laser confocal microscopy as objects mostly oval or nearly oval form. The diameter of myocytes, assessed by photon correlation spectroscopy, was amounted 7-10 microm which is Consistent with the results obtained by using laser confocal microscopy. It is shown that the myoconstricted agents as Ca2+ ionophore A-23187 (10 microM) and K(+)-channels inhibitors (tetraethylammonium and 4-aminopyridine in a concentration of 1 mM) leading to decrease the diameter of the cells by 22%, 12% and 24% in average respectively. The ouabain, that reduces contractile activity of smooth muscle, leads to increase this parameter up 23% from control. Thus, decreasing/increasing the diameter of uterine myocytes correlates with their well known influence on myometrium constriction/relaxation.
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Kodera SY, Yoshida M, Dezaki K, Yada T, Murayama T, Kawakami M, Kakei M. Inhibition of insulin secretion from rat pancreatic islets by dexmedetomidine and medetomidine, two sedatives frequently used in clinical settings. Endocr J 2013; 60:337-46. [PMID: 23171706 DOI: 10.1507/endocrj.ej12-0308] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The aim of this study was to determine whether dexmedetomidine (DEX) and medetomidine (MED), α2-adrenergic agonists clinically used as sedatives, influence insulin secretion from rat pancreatic islets. Islets were isolated from adult male Wistar rats after collagenase digestion. Static incubation was used to determine effects of DEX or MED on insulin secretion and ionic-channel currents of β-cells. Results indicate that both drugs dose-dependently inhibit insulin secretion, DEX more potently than MED. The inhibitory effects were attenuated by addition of yohimbine or by pretreatment of rats with pertussis toxin (PTX). 10 nM DEX decreased the current amplitude of voltage-dependent Ca2+ channels, but this did not occur when the N-type Ca2+ channel blocker ω-conotoxin was added. In the presence of tetraethylammonium, a classical voltage-gated K+ channel (Kv channel) blocker, the magnitude of inhibition of insulin secretion by MED was reduced. However, when tolbutamide, a specific blocker of the ATP-sensitive K+ channel (KATP channel), was present, the magnitude of MED inhibition of insulin secretion was not influenced, suggesting that Kv-channel activity alteration, but not that of KATP channels, is involved in MED-associated insulin secretory inhibition. The Kv-channel currents were increased during 1 nM MED exposure at membrane potentials ranging from -30 mV to -10 mV, where action potentials were generated in response to glucose stimulation. These results indicate that DEX and MED inhibit insulin secretion through an α2-adrenoceptor and PTX-sensitive GTP-binding protein pathway that eventually involves Kv channel activation and Ca2+ channel inhibition.
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Affiliation(s)
- Shiho Yamato Kodera
- Division of Anesthesiology, Second Department of General Medicine, Saitama Medical Center, Jichi Medical University School of Medicine, Omiya 330-8503, Japan
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Yim PD, Gallos G, Perez-Zoghbi JF, Trice J, Zhang Y, Siviski M, Sonett J, Emala CW. Chloride channel blockers promote relaxation of TEA-induced contraction in airway smooth muscle. J Smooth Muscle Res 2013; 49:112-24. [PMID: 24662476 PMCID: PMC4131261 DOI: 10.1540/jsmr.49.112] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 12/19/2013] [Indexed: 01/21/2023] Open
Abstract
Enhanced airway smooth muscle (ASM) contraction is an important component in the pathophysiology of asthma. We have shown that ligand gated chloride channels modulate ASM contractile tone during the maintenance phase of an induced contraction, however the role of chloride flux in depolarization-induced contraction remains incompletely understood. To better understand the role of chloride flux under these conditions, muscle force (human ASM, guinea pig ASM), peripheral small airway luminal area (rat ASM) and airway smooth muscle plasma membrane electrical potentials (human cultured ASM) were measured. We found ex vivo guinea pig airway rings, human ASM strips and small peripheral airways in rat lungs slices relaxed in response to niflumic acid following depolarization-induced contraction induced by K(+) channel blockade with tetraethylammonium chloride (TEA). In isolated human airway smooth muscle cells TEA induce depolarization as measured by a fluorescent indicator or whole cell patch clamp and this depolarization was reversed by niflumic acid. These findings demonstrate that ASM depolarization induced contraction is dependent on chloride channel activity. Targeting of chloride channels may be a novel approach to relax hypercontractile airway smooth muscle in bronchoconstrictive disorders.
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Affiliation(s)
- Peter D Yim
- Departments of Anesthesiology, College of Physicians and Surgeons of Columbia University, New York, NY USA
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Tep-Areenan P, Suksamrarn S. Mechanisms of vasorelaxation to gamma-mangostin in the rat aorta. J Med Assoc Thai 2012; 95 Suppl 12:S63-S68. [PMID: 23513467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
OBJECTIVE To investigate the effects of gamma-mangostin on vascular tone and its mechanisms in the isolated rat aorta. MATERIAL AND METHOD Aortic rings from male Wistar rats were precontracted with methoxamine. Changes in tension were measured using an isometric force transducer and recorded on the MacLab recording system. Vasorelaxant effects of gamma-mangostin were studied in the presence of 300 microM N(G)-nitro L-arginine methyl ester (L-NAME), 10 microM 1H-[1,2,4] oxadiazolo-[4,3-a] quinoxalin-1-one (ODQ), 10 microM indomethacin, 60 mM KCl, 5 mM tetraethylammonium (TEA), 10 microM glibenclamide, 1 mM4-aminopyridine (4-AP) or 30 microM barium chloride (BaCl2). Moreover the effects of gamma-mangostin on contraction to CaCl2 were evaluated. RESULTS Gamma-mangostin (1-100 microM) induced a concentration-dependent vasorelaxation in rat aortic rings precontracted with methoxamine. This effect was significantly reduced after removal of the endothelium and after pretreatment of the rings with L-NAME, ODQ, high KCl solution, or TEA. However, vasorelaxant responses to gamma-mangostin were not altered by indomethacin, 4-AP, BaCl2 or glibenclamide. Moreover, contractions to CaCl2 (10 mM-30 mM) were reduced by pre-treatment with gamma-mangostin (10 and 100 microM). CONCLUSION Gamma-mangostin causes vasorelaxation which is mediated via the NO-cGMP pathway. Moreover activation of K+ channels and inhibition of extracellular Ca2+ influx from the extracellular space are largely involved in the relaxant effects of gamma-mangostin. These data suggest that gamma-mangostin may acts as an antihypertensive agent.
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Affiliation(s)
- Patcharin Tep-Areenan
- Department of Physiology, Faculty of Medicine, Srinakharinwirot University, Bangkok, Thailand.
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Gaydukov AE, Marchenkova AA, Balezina OP. Involvement of basal and calcium-activated protein kinase C in neurotransmitter secretion in mouse motor synapses. Bull Exp Biol Med 2012; 153:820-3. [PMID: 23113293 DOI: 10.1007/s10517-012-1834-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Blocker of presynaptic protein kinase C isoforms, GF109203X, reduced quantal content of single and rhythmic evoked end-plate potentials. The increase in quantal content of single potentials under the effect of 4- aminopyridine was neutralized by 75% under the effect of L-type Ca(2+)-channel blocker nitrendipine and completely returned to the control level after protein kinase C inhibition with chelerythrine. Neither nitrendipine, nor GF109203X affected the potentiating effect of tetraethylammonium on quantal content of end-plate potentials. Thus, we discovered basal activity of presynaptic protein kinase C under normal conditions that is aimed at the maintenance of quantal content of evoked release. It has been concluded that 4-aminipyridine, but not tetraethylammonium, triggers Ca(2+) entry into the terminal, which activates protein kinase C and enhanced the evoked acetylcholine release.
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Affiliation(s)
- A E Gaydukov
- Department of Human and Animal Physiology, Biological Faculty, M. V. Lomonosov Moscow State University, Russia.
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Masino MA, Abbinanti MD, Eian J, Harris-Warrick RM. TTX-resistant NMDA receptor-mediated membrane potential oscillations in neonatal mouse Hb9 interneurons. PLoS One 2012; 7:e47940. [PMID: 23094101 PMCID: PMC3475713 DOI: 10.1371/journal.pone.0047940] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 09/25/2012] [Indexed: 01/08/2023] Open
Abstract
Conditional neuronal membrane potential oscillations have been identified as a potential mechanism to help support or generate rhythmogenesis in neural circuits. A genetically identified population of ventromedial interneurons, called Hb9, in the mouse spinal cord has been shown to generate TTX-resistant membrane potential oscillations in the presence of NMDA, serotonin and dopamine, but these oscillatory properties are not well characterized. Hb9 interneurons are rhythmically active during fictive locomotor-like behavior. In this study, we report that exogenous N-Methyl-D-Aspartic acid (NMDA) application is sufficient to produce membrane potential oscillations in Hb9 interneurons. In contrast, exogenous serotonin and dopamine application, alone or in combination, are not sufficient. The properties of NMDA-induced oscillations vary among the Hb9 interneuron population; their frequency and amplitude increase with increasing NMDA concentration. NMDA does not modulate the T-type calcium current (ICa(T)), which is thought to be important in generating locomotor-like activity, in Hb9 neurons. These results suggest that NMDA receptor activation is sufficient for the generation of TTX-resistant NMDA-induced membrane potential oscillations in Hb9 interneurons.
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Affiliation(s)
- Mark A Masino
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota, United States of America.
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Zhang DM, Li Y, Cheang WS, Lau CW, Lin SM, Zhang QL, Yao N, Wang Y, Wu X, Huang Y, Ye WC. Cajaninstilbene acid relaxes rat renal arteries: roles of Ca2+ antagonism and protein kinase C-dependent mechanism. PLoS One 2012; 7:e47030. [PMID: 23056567 PMCID: PMC3467215 DOI: 10.1371/journal.pone.0047030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2012] [Accepted: 09/07/2012] [Indexed: 11/30/2022] Open
Abstract
Cajaninstilbene acid (CSA) is a major active component present in the leaves of Cajanus cajan (L.) Millsp. The present study explores the underlying cellular mechanisms for CSA-induced relaxation in rat renal arteries. Vascular reactivity was examined in arterial rings that were suspended in a Multi Myograph System and the expression of signaling proteins was assessed by Western blotting method. CSA (0.1–10 µM) produced relaxations in rings pre-contracted by phenylephrine, serotonin, 9, 11-dideoxy-9α, 11α-epoxymethanoprostaglandin F2α (U46619), and 60 mM KCl. CSA-induced relaxations did not show difference between genders and were unaffected by endothelium denudation, nor by treatment with NG-nitro-L-arginine methyl ester, indomethacin, ICI-182780, tetraethylammonium ion, BaCl2, glibenclamide, 4-aminopyridine or propranolol. CSA reduced contraction induced by CaCl2 (0.01–5 mM) in Ca2+-free 60 mM KCl solution and by 30 nM (−)-Bay K8644 in 15 mM KCl solution. CSA inhibited 60 mM KCl-induced Ca2+ influx in smooth muscle of renal arteries. In addition, CSA inhibited contraction evoked by phorbol 12-myristate 13-acetate (PMA, protein kinase C agonist) in Ca2+-free Krebs solution. Moreover, CSA reduced the U46619- and PMA-induced phosphorylation of myosin light chain (MLC) at Ser19 and myosin phosphatase target subunit 1 (MYPT1) at Thr853 which was associated with vasoconstriction. CSA also lowered the phosphorylation of protein kinase C (PKCδ) at Thr505. In summary, the present results suggest that CSA relaxes renal arteries in vitro via multiple cellular mechanisms involving partial inhibition of calcium entry via nifedipine-sensitive calcium channels, protein kinase C and Rho kinase.
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Affiliation(s)
- Dong-Mei Zhang
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, Guangzhou, China
- Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine and New Drugs Research, Jinan University, Guangzhou, China
| | - Yong Li
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, Guangzhou, China
- Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine and New Drugs Research, Jinan University, Guangzhou, China
| | - Wai San Cheang
- Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences and School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Chi Wai Lau
- Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences and School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Shun-Ming Lin
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, Guangzhou, China
- Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine and New Drugs Research, Jinan University, Guangzhou, China
| | - Qian-Lan Zhang
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, Guangzhou, China
- Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine and New Drugs Research, Jinan University, Guangzhou, China
| | - Nan Yao
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, Guangzhou, China
- Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine and New Drugs Research, Jinan University, Guangzhou, China
| | - Ying Wang
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, Guangzhou, China
- Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine and New Drugs Research, Jinan University, Guangzhou, China
| | - Xin Wu
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, Guangzhou, China
- Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine and New Drugs Research, Jinan University, Guangzhou, China
| | - Yu Huang
- Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences and School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
- * E-mail: (WCY); (YH)
| | - Wen-Cai Ye
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, Guangzhou, China
- Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine and New Drugs Research, Jinan University, Guangzhou, China
- * E-mail: (WCY); (YH)
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43
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Alvarez P, Chen X, Hendrich J, Irwin JC, Green PG, Giudice LC, Levine JD. Ectopic uterine tissue as a chronic pain generator. Neuroscience 2012; 225:269-82. [PMID: 22922120 DOI: 10.1016/j.neuroscience.2012.08.033] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 08/13/2012] [Accepted: 08/15/2012] [Indexed: 11/16/2022]
Abstract
While chronic pain is a main symptom in endometriosis, the underlying mechanisms and effective therapy remain elusive. We developed an animal model enabling the exploration of ectopic endometrium as a source of endometriosis pain. Rats were surgically implanted with autologous uterus in the gastrocnemius muscle. Within two weeks, visual inspection revealed the presence of a reddish-brown fluid-filled cystic structure at the implant site. Histology demonstrated cystic glandular structures with stromal invasion of the muscle. Immunohistochemical studies of these lesions revealed the presence of markers for nociceptor nerve fibers and neuronal sprouting. Fourteen days after surgery rats exhibited persistent mechanical hyperalgesia at the site of the ectopic endometrial lesion. Intralesional, but not contralateral, injection of progesterone was dose-dependently antihyperalgesic. Systemic administration of leuprolide also produced antihyperalgesia. In vivo electrophysiological recordings from sensory neurons innervating the lesion revealed a significant increase in their response to sustained mechanical stimulation. These results are consistent with clinical and pathological findings observed in patients with endometriosis, compatible with the ectopic endometrium as a source of pain. This model of endometriosis allows mechanistic exploration at the lesion site facilitating our understanding of endometriosis pain.
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Affiliation(s)
- P Alvarez
- Department of Oral and Maxillofacial Surgery, University of California San Francisco, San Francisco, CA, USA
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44
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Sitdikova GF, Khaertdinov NN, Zefirov AL. Role of calcium and potassium channels in effects of hydrogen sulfide on frog myocardial contractility. Bull Exp Biol Med 2012; 151:163-6. [PMID: 22238741 DOI: 10.1007/s10517-011-1280-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The effects of sodium hydrosulfide NaHS, a donor of hydrogen sulfide H2S, on the force of muscle contraction were examined on isolated myocardial strips from frog ventricles. NaHS decreased the amplitude of muscle contractions in a dose-dependent manner under normal conditions and during inhibition of Ca channels with nifedipine. In contrast, under conditions of blockade of ATP-dependent potassium channels with glibenclamide, NaHS exerted a positive inotropic effect from the first minute of application. Neither blockade, nor activation of ATP-dependent K-channels with glibenclamide modulated the negative inotropic effect of NaHS. Inhibition of K-channels with tetraethylammonium (TEA) (3, 5, 10 mM) or 4-aminopyridine increased the amplitude of myocardial contractions. Preliminary application of 4-aminopyridine or TEA (3 mM) did not eliminate NaHS-induced negative inotropic effect, although higher TEA concentrations (5 or 10 mM) prevented it. The data indicate that the targets of H(2)S in frog myocardium are ATP-dependent, Ca-activated, and voltage-dependent K-channels.
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Affiliation(s)
- G F Sitdikova
- Department of Human and Animal Physiology, Kazan (Privolzhskii) Federal University, Russia.
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45
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Breĭgina MA, Matveeva NP, Andreiuk DS, Ermakov IP. [Transmembrane transport of K+ and Cl- during pollen grain activation in vivo and in vitro]. Ontogenez 2012; 43:103-12. [PMID: 22650076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We studied the possibility of K+ and Cl- efflux from tobacco pollen grains during their activation in vitro or on the stigma of a pistil. For this purpose the X-ray microanalysis and spectrofluorometry were applied. We found that the relative content of potassium and chlorine in the microvolume of pollen grain decreases during its hydration and activation on stigma. Efflux of these ions was found both in vivo and in vitro. In model in vitro experiments anion channel inhibitor NPPB ((5-nitro-2-(3-phenylpropylamino) benzoic acid) in the concentration that was blocking pollen germination, reduced Cl- efflux; potassium channel inhibitor (tetraethylammonium chloride) partially reduced K+ efflux and lowered the percent of activated cells. Another blocker of potassium channels Ba2+ caused severe decrease in cell volume and blocked the activation. In general, the obtained data demonstrates that the initiation of pollen germination both in vivo and in vitro involves the activation of K+ and Cl- release. An important role in these processes is played by NPPB-, TEA- and Ba(2+)-sensitive plasmalemma ion channels.
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46
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Abstract
We present a microfluidic device to generate either statically spatial or dynamically temporal logarithmic concentrations. The temporal logarithmic concentration generator was also integrated with planar patch-clamp chips for dose-response assays on ion channels. Proposed serial dilution principle controls the flow pattern at each branching point via designing the flow resistance of microchannels. Simple and linear ratios of the flow resistance results in desired logarithmic concentration at outlets, where the concentrations can be dynamically altered by different combination of valve actuations, were demonstrated. Single-cell pharmacology on ion channels was implemented by sequentially applying logarithmic drug concentrations to patched cells. Inhibitory activity of potassium channels of human embryonic kidney cells was examined by tetraethylammonium solutions. Resulted IC(50) and Hill slope reveal excellent agreement with assays from manually prepared drug concentrations showing the practicability and preciseness of the present approach. Applications include cellular analysis under various drugs and/or logarithmic concentrations at the single-cell level.
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Affiliation(s)
- Chang-Yu Chen
- Institute of Applied Mechanics, National Taiwan University, Taipei 106, Taiwan
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47
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Queiroz TM, Machado NT, Furtado FF, Oliveira-Filho AA, Alustau MC, Figueiredo CS, Miranda GEC, Barbosa-Filho JM, Braga VA, Medeiros IA. Vasorelaxation, induced by Dictyota pulchella (Dictyotaceae), a brown alga, is mediated via inhibition of calcium influx in rats. Mar Drugs 2011; 9:2075-2088. [PMID: 22073010 PMCID: PMC3210619 DOI: 10.3390/md9102075] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 10/13/2011] [Accepted: 10/17/2011] [Indexed: 01/05/2023] Open
Abstract
This study aimed to investigate the cardiovascular effects elicited by Dictyota pulchella, a brown alga, using in vivo and in vitro approaches. In normotensive conscious rats, CH(2)Cl(2)/MeOH Extract (CME, 5, 10, 20 and 40 mg/kg) from Dictyota pulchella produced dose-dependent hypotension (-4 ± 1; -8 ± 2; -53 ± 8 and -63 ± 3 mmHg) and bradycardia (-8 ± 6; -17 ± 11; -257 ± 36 and -285 ± 27 b.p.m.). In addition, CME and Hexane/EtOAc Phase (HEP) (0.01-300 μg/mL) from Dictyota pulchella induced a concentration-dependent relaxation in phenylephrine (Phe, 1 μM)-pre-contracted mesenteric artery rings. The vasorelaxant effect was not modified by the removal of the vascular endothelium or pre-incubation with KCl (20 mM), tetraethylammonium (TEA, 3 mM) or tromboxane A(2) agonist U-46619 (100 nM). Furthermore, CME and HEP reversed CaCl(2)-induced vascular contractions. These results suggest that both CME and HEP act on the voltage-operated calcium channel in order to produce vasorelaxation. In addition, CME induced vasodilatation after the vessels have been pre-contracted with L-type Ca(2+) channel agonist (Bay K 8644, 200 nM). Taken together, our data show that CME induces hypotension and bradycardia in vivo and that both CME and HEP induce endothelium-independent vasodilatation in vitro that seems to involve the inhibition of the Ca(2+) influx through blockade of voltage-operated calcium channels.
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MESH Headings
- 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid/pharmacology
- 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester/pharmacology
- Animals
- Biological Products/pharmacology
- Calcium Channel Blockers/pharmacology
- Calcium Channels/drug effects
- Dose-Response Relationship, Drug
- Male
- Muscle, Smooth, Vascular/drug effects
- Phaeophyceae/chemistry
- Phenylephrine/pharmacology
- Potassium Chloride/pharmacology
- Rats
- Rats, Wistar
- Tetraethylammonium/pharmacology
- Vasodilation/drug effects
- Vasodilator Agents/pharmacology
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Affiliation(s)
- Thyago M. Queiroz
- Biotechnology Center, Federal University of Paraiba, João Pessoa, PB 58.051-900, Brazil; E-Mails: (T.M.Q.); (N.T.M.); (F.F.F.); (A.A.O.-F); (M.C.A); (C.S.F.); (G.E.C.M.); (J.M.B.-F.); (I.A.M.)
| | - Natália T. Machado
- Biotechnology Center, Federal University of Paraiba, João Pessoa, PB 58.051-900, Brazil; E-Mails: (T.M.Q.); (N.T.M.); (F.F.F.); (A.A.O.-F); (M.C.A); (C.S.F.); (G.E.C.M.); (J.M.B.-F.); (I.A.M.)
| | - Fabíola F. Furtado
- Biotechnology Center, Federal University of Paraiba, João Pessoa, PB 58.051-900, Brazil; E-Mails: (T.M.Q.); (N.T.M.); (F.F.F.); (A.A.O.-F); (M.C.A); (C.S.F.); (G.E.C.M.); (J.M.B.-F.); (I.A.M.)
| | - Abrahão A. Oliveira-Filho
- Biotechnology Center, Federal University of Paraiba, João Pessoa, PB 58.051-900, Brazil; E-Mails: (T.M.Q.); (N.T.M.); (F.F.F.); (A.A.O.-F); (M.C.A); (C.S.F.); (G.E.C.M.); (J.M.B.-F.); (I.A.M.)
| | - Maria C. Alustau
- Biotechnology Center, Federal University of Paraiba, João Pessoa, PB 58.051-900, Brazil; E-Mails: (T.M.Q.); (N.T.M.); (F.F.F.); (A.A.O.-F); (M.C.A); (C.S.F.); (G.E.C.M.); (J.M.B.-F.); (I.A.M.)
| | - Camila S. Figueiredo
- Biotechnology Center, Federal University of Paraiba, João Pessoa, PB 58.051-900, Brazil; E-Mails: (T.M.Q.); (N.T.M.); (F.F.F.); (A.A.O.-F); (M.C.A); (C.S.F.); (G.E.C.M.); (J.M.B.-F.); (I.A.M.)
| | - George E. C. Miranda
- Biotechnology Center, Federal University of Paraiba, João Pessoa, PB 58.051-900, Brazil; E-Mails: (T.M.Q.); (N.T.M.); (F.F.F.); (A.A.O.-F); (M.C.A); (C.S.F.); (G.E.C.M.); (J.M.B.-F.); (I.A.M.)
| | - José M. Barbosa-Filho
- Biotechnology Center, Federal University of Paraiba, João Pessoa, PB 58.051-900, Brazil; E-Mails: (T.M.Q.); (N.T.M.); (F.F.F.); (A.A.O.-F); (M.C.A); (C.S.F.); (G.E.C.M.); (J.M.B.-F.); (I.A.M.)
| | - Valdir A. Braga
- Biotechnology Center, Federal University of Paraiba, João Pessoa, PB 58.051-900, Brazil; E-Mails: (T.M.Q.); (N.T.M.); (F.F.F.); (A.A.O.-F); (M.C.A); (C.S.F.); (G.E.C.M.); (J.M.B.-F.); (I.A.M.)
| | - Isac A. Medeiros
- Biotechnology Center, Federal University of Paraiba, João Pessoa, PB 58.051-900, Brazil; E-Mails: (T.M.Q.); (N.T.M.); (F.F.F.); (A.A.O.-F); (M.C.A); (C.S.F.); (G.E.C.M.); (J.M.B.-F.); (I.A.M.)
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48
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Yu XZ, Li F, Li K. A possible new mechanism involved in ferro-cyanide metabolism by plants. Environ Sci Pollut Res Int 2011; 18:1343-50. [PMID: 21465162 DOI: 10.1007/s11356-011-0489-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Accepted: 03/09/2011] [Indexed: 05/30/2023]
Abstract
BACKGROUND, AIM, AND SCOPE Ferro-cyanide is one of the commonly found species at cyanide-contaminated soils and groundwater. Unlike botanical metabolism of KCN via the β-cyanoalanine pathway, processes involved in the plant-mediated assimilation of ferro-cyanide are still unclear. The objective of this study was to investigate a possible mechanism involved in uptake and assimilation of ferro-cyanide by plants. MATERIALS AND METHODS Detached roots of plants were exposed to ferro-cyanide in a closed-dark hydroponic system amended with HgCl(2), AgNO(3), LaCl(3), tetraethylammonium chloride (TEACl), or Na(3)VO(4), respectively, at 25 ± 0.5°C for 24 h. Total CN, free CN(-), and dissolved Fe(2+) were analyzed spectrophotometrically. Activity of β-cyanoalanine synthase involved in cyanide assimilation was also assayed using detached roots of plants in vivo. RESULTS Dissociation of ferro-cyanide [Fe(II)(CN)(6)](-4) to free CN(-) and Fe(2+) in solution was negligible. The applied inhibitors did not show any significant impact on the uptake of ferro-cyanide by soybean (Glycine max L. cv. JD 1) and hybrid willows (Salix matsudana Koidz × alba L.; p > 0.05), but rice (Oryza sativa L. cv. JY 98) was more susceptible to the inhibitors compared with the controls (p < 0.05). However, TEACl had the most severe effect on the assimilation of ferro-cyanide by soybean, hybrid willows, and maize (Zea mays L. cv. PA 78; p < 0.01), whereas AgNO(3) was the most sensitive inhibitor to rice (p < 0.01). No measurable difference in β-cyanoalanine synthase activity of roots exposed to ferro-cyanide was observed compared with the control without any cyanides (p > 0.05), whereas roots exposed to KCN showed a considerable increase in enzyme activity (p < 0.05). CONCLUSIONS Plants take up Fe(2+) and CN(-) as a whole complex, and in vivo dissociation to free CN(-) is not prerequisite during the botanical assimilation of ferro-cyanide. Ferro-cyanide is likely metabolized by plants directly through an unknown pathway rather than the β-cyanoalanine pathway.
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Affiliation(s)
- Xiao-Zhang Yu
- Department of Environmental Sciences and Engineering, Hunan Agricultural University, Changsha 410128, People's Republic of China.
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49
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Wegner LH, Flickinger B, Eing C, Berghöfer T, Hohenberger P, Frey W, Nick P. A patch clamp study on the electro-permeabilization of higher plant cells: Supra-physiological voltages induce a high-conductance, K+ selective state of the plasma membrane. Biochim Biophys Acta 2011; 1808:1728-36. [PMID: 21296050 DOI: 10.1016/j.bbamem.2011.01.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Revised: 01/26/2011] [Accepted: 01/28/2011] [Indexed: 11/30/2022]
Abstract
Permeabilization of biological membranes by pulsed electric fields ("electroporation") is frequently used as a tool in biotechnology. However, the electrical properties of cellular membranes at supra-physiological voltages are still a topic of intensive research efforts. Here, the patch clamp technique in the whole cell and the outside out configuration was employed to monitor current-voltage relations of protoplasts derived from the tobacco culture cell line "Bright yellow-2". Cells were exposed to a sequence of voltage pulses including supra-physiological voltages. A transition from a low-conductance (~0.1 nS/pF) to a high-conductance state (~5 nS/pF) was observed when the membrane was either hyperpolarized or depolarized beyond threshold values of around -250 to -300 mV and +200 to +250 mV, respectively. Current-voltage curves obtained with ramp protocols revealed that the electro-permeabilized membrane was 5-10 times more permeable to K+ than to gluconate. The K+ channel blocker tetraethylammonium (25 mM) did not affect currents elicited by 10 ms-pulses, suggesting that the electro-permeabilization was not caused by a non-physiological activation of K+ channels. Supra-physiological voltage pulses even reduced "regular" K+ channel activity, probably due to an increase of cytosolic Ca2+ that is known to inhibit outward-rectifying K+ channels in Bright yellow-2 cells. Our data are consistent with a reversible formation of aqueous membrane pores at supra-physiological voltages.
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Affiliation(s)
- Lars H Wegner
- Karlsruhe Institute of Technology, Institute for Pulsed Power and Microwave Technology (IHM), Campus North, 76344 Eggenstein-Leopoldshafen, Germany; Karlsruhe Institute of Technology, Botanical Institute I-Molecular Cell Biology, Campus South, 76131 Karlsruhe, Germany.
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50
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Abstract
Abstract
The abnormally low activity of tetraethylammonium at the neuromuscular junction of the rat-diaphragm has been investigated. It seems possible to explain this lack of action in terms of the charge delocalisation and the stereochemistry of tetraethylammonium. The neuromuscular blocking activities of tetraethylammonium, isomers of it and related quaternary ammonium compounds have been determined and the structure activity relationships are discussed
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