1
|
Rehman NU, Ansari MN, Samad A, Ahmad W. In Silico and Ex Vivo Studies on the Spasmolytic Activities of Fenchone Using Isolated Guinea Pig Trachea. Molecules 2022; 27:molecules27041360. [PMID: 35209147 PMCID: PMC8876211 DOI: 10.3390/molecules27041360] [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] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 02/11/2022] [Accepted: 02/14/2022] [Indexed: 01/25/2023] Open
Abstract
Fenchone is a bicyclic monoterpene found in a variety of aromatic plants, including Foeniculum vulgare and Peumus boldus, and is used in the management of airways disorders. This study aimed to explore the bronchodilator effect of fenchone using guinea pig tracheal muscles as an ex vivo model and in silico studies. A concentration-mediated tracheal relaxant effect of fenchone was evaluated using isolated guinea pig trachea mounted in an organ bath provided with physiological conditions. Sustained contractions were achieved using low K+ (25 mM), high K+ (80 mM), and carbamylcholine (CCh; 1 µM), and fenchone inhibitory concentration–response curves (CRCs) were obtained against these contractions. Fenchone selectively inhibited with higher potency contractions evoked by low K+ compared to high K+ with resultant EC50 values of 0.62 mg/mL (0.58–0.72; n = 5) and 6.44 mg/mL (5.86–7.32; n = 5), respectively. Verapamil (VRP) inhibited both low and high K+ contractions at similar concentrations. Pre-incubation of the tracheal tissues with K+ channel blockers such as glibenclamide (Gb), 4-aminopyridine (4-AP), and tetraethylammonium (TEA) significantly shifted the inhibitory CRCs of fenchone to the right towards higher doses. Fenchone also inhibited CCh-mediated contractions at comparable potency to its effect against high K+ [6.28 mg/mL (5.88–6.42, n = 4); CCh] and [6.44 mg/mL (5.86–7.32; n = 5); high K+]. A similar pattern was obtained with papaverine (PPV), a phosphodiesterase (PDE), and Ca2+ inhibitor which inhibited both CCh and high K+ at similar concentrations [10.46 µM (9.82–11.22, n = 4); CCh] and [10.28 µM (9.18–11.36; n = 5); high K+]. However, verapamil, a standard Ca2+ channel blocker, showed selectively higher potency against high K+ compared to CCh-mediated contractions with respective EC50 values of 0.84 mg/mL (0.82–0.96; n = 5) 14.46 mg/mL (12.24–16.38, n = 4). The PDE-inhibitory action of fenchone was further confirmed when its pre-incubation at 3 and 5 mg/mL potentiated and shifted the isoprenaline inhibitory CRCs towards the left, similar to papaverine, whereas the Ca2+ inhibitory-like action of fenchone pretreated tracheal tissues were authenticated by the rightward shift of Ca2+ CRCs with suppression of maximum response, similar to verapamil, a standard Ca2+ channel blocker. Fenchone showed a spasmolytic effect in isolated trachea mediated predominantly by K+ channel activation followed by dual inhibition of PDE and Ca2+ channels. Further in silico molecular docking studies provided the insight for binding of fenchone with Ca2+ channel (−5.3 kcal/mol) and K+ channel (−5.7), which also endorsed the idea of dual inhibition.
Collapse
Affiliation(s)
- Najeeb Ur Rehman
- Department of Pharmacology & Toxicology, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia
- Correspondence: (N.U.R.); (M.N.A.); Tel.: +966-11-5886-035 (N.U.R.); +966-11-5886-037 (M.N.A.)
| | - Mohd Nazam Ansari
- Department of Pharmacology & Toxicology, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia
- Correspondence: (N.U.R.); (M.N.A.); Tel.: +966-11-5886-035 (N.U.R.); +966-11-5886-037 (M.N.A.)
| | - Abdul Samad
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Tishk International University, Erbil 44001, Iraq;
| | - Wasim Ahmad
- Department of Pharmacy, Mohammed Al-Mana College for Medical Sciences, Dammam 34222, Saudi Arabia;
| |
Collapse
|
2
|
Wrzosek A, Gałecka S, Żochowska M, Olszewska A, Kulawiak B. Alternative Targets for Modulators of Mitochondrial Potassium Channels. Molecules 2022; 27:299. [PMID: 35011530 PMCID: PMC8746388 DOI: 10.3390/molecules27010299] [Citation(s) in RCA: 1] [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: 11/18/2021] [Revised: 12/30/2021] [Accepted: 12/31/2021] [Indexed: 12/17/2022] Open
Abstract
Mitochondrial potassium channels control potassium influx into the mitochondrial matrix and thus regulate mitochondrial membrane potential, volume, respiration, and synthesis of reactive oxygen species (ROS). It has been found that pharmacological activation of mitochondrial potassium channels during ischemia/reperfusion (I/R) injury activates cytoprotective mechanisms resulting in increased cell survival. In cancer cells, the inhibition of these channels leads to increased cell death. Therefore, mitochondrial potassium channels are intriguing targets for the development of new pharmacological strategies. In most cases, however, the substances that modulate the mitochondrial potassium channels have a few alternative targets in the cell. This may result in unexpected or unwanted effects induced by these compounds. In our review, we briefly present the various classes of mitochondrial potassium (mitoK) channels and describe the chemical compounds that modulate their activity. We also describe examples of the multidirectional activity of the activators and inhibitors of mitochondrial potassium channels.
Collapse
Affiliation(s)
- Antoni Wrzosek
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.W.); (S.G.); (M.Ż.)
| | - Shur Gałecka
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.W.); (S.G.); (M.Ż.)
| | - Monika Żochowska
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.W.); (S.G.); (M.Ż.)
| | - Anna Olszewska
- Department of Histology, Medical University of Gdansk, 1a Debinki, 80-211 Gdansk, Poland;
| | - Bogusz Kulawiak
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.W.); (S.G.); (M.Ż.)
| |
Collapse
|
3
|
Abstract
Neonatal seizures are a common neurologic emergency for which therapies have not significantly changed in decades. Improvements in diagnosis and pathophysiologic understanding of the distinct features of acute symptomatic seizures and neonatal-onset epilepsies present exceptional opportunities for development of precision therapies with potential to improve outcomes. Herein, we discuss the pathophysiology of neonatal seizures and review the evidence for currently available treatment. We present emerging therapies in clinical and preclinical development for the treatment of acute symptomatic neonatal seizures. Lastly, we discuss the role of precision therapies for genetic neonatal-onset epilepsies and address barriers and goals for developing new therapies for clinical care.
Collapse
Affiliation(s)
- Julie M Ziobro
- Department of Pediatrics, Michigan Medicine, C.S. Mott Children's Hospital, University of Michigan, 1540 E. Hospital Dr, Ann Arbor, MI, USA.
| | - Krista Eschbach
- Department of Pediatrics, Section of Neurology, Denver Anschutz School of Medicine, Children's Hospital Colorado, University of Colorado, Aurora, CO, 80045, USA
| | - Renée A Shellhaas
- Department of Pediatrics, Michigan Medicine, C.S. Mott Children's Hospital, University of Michigan, 1540 E. Hospital Dr, Ann Arbor, MI, USA
| |
Collapse
|
4
|
Serviente C, Berry CW, Kenney WL, Alexander LM. Healthy active older adults have enhanced K + channel-dependent endothelial vasodilatory mechanisms. Am J Physiol Regul Integr Comp Physiol 2020; 319:R19-R25. [PMID: 32401629 PMCID: PMC7468792 DOI: 10.1152/ajpregu.00049.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [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: 03/05/2020] [Revised: 04/10/2020] [Accepted: 05/11/2020] [Indexed: 12/21/2022]
Abstract
Microvascular endothelial dysfunction, a precursor to atherosclerotic cardiovascular disease, increases with aging. Endothelium-derived hyperpolarizing factors (EDHFs), which act through K+ channels, regulate blood flow and are important to vascular health. It is unclear how EDHFs change with healthy aging. To evaluate microvascular endothelial reliance on K+ channel-mediated dilation as a function of age in healthy humans. Microvascular function was assessed using intradermal microdialysis in healthy younger (Y; n = 7; 3 M/4 W; 26 ± 1 yr) and older adults (O; n = 12; 5 M/7 W; 64 ± 2 yr) matched for V̇o2peak (Y: 39.0 ± 3.8, O: 37.6 ± 3.1 mL·kg-1·min-1). Participants underwent graded local infusions of: the K+ channel activator Na2S (10-6 to 10-1 M), acetylcholine (ACh, 10-10 to 10-1 M), ACh + the K+ channel inhibitor tetraethylammonium (TEA; 25 or 50 mM), and ACh + the nitric oxide synthase-inhibitor l-NAME (15 mM). Red blood cell flux was measured with laser-Doppler flowmetry and used to calculate cutaneous vascular conductance (CVC; flux/mean arterial pressure) as a percentage of each site-specific maximum (%CVCmax, 43°C+28 mM sodium nitroprusside). The %CVCmax response to Na2S was higher in older adults (mean, O: 51.7 ± 3.9% vs. Y: 36.1 ± 5.3%; P = 0.03). %CVCmax was lower in the ACh+TEA vs. the ACh site starting at 10-5 M (ACh: 34.0 ± 5.7% vs. ACh+TEA: 19.4 ± 4.5%; P = 0.002) in older and at 10-4 M (ACh: 54.5 ± 9.4% vs. ACh+TEA: 31.2 ± 6.7%; P = 0.0002) in younger adults. %CVCmax was lower in the ACh+l-NAME vs. the ACh site in both groups starting at 10-4 M ACh (Y: P < 0.001; O: P = 0.02). Healthy active older adults have enhanced K+ channel-dependent endothelial vasodilatory mechanisms, suggesting increased responsiveness to EDHFs with age.
Collapse
Affiliation(s)
- Corinna Serviente
- Department of Kinesiology, Pennsylvania State University, University Park, Pennsylvania
- Center for Healthy Aging, Pennsylvania State University, University Park, Pennsylvania
| | - Craig W Berry
- Department of Kinesiology, Pennsylvania State University, University Park, Pennsylvania
| | - W Larry Kenney
- Department of Kinesiology, Pennsylvania State University, University Park, Pennsylvania
- Center for Healthy Aging, Pennsylvania State University, University Park, Pennsylvania
| | - Lacy M Alexander
- Department of Kinesiology, Pennsylvania State University, University Park, Pennsylvania
- Center for Healthy Aging, Pennsylvania State University, University Park, Pennsylvania
| |
Collapse
|
5
|
Romero F, Palacios J, Jofré I, Paz C, Nwokocha CR, Paredes A, Cifuentes F. Aristoteline, an Indole-Alkaloid, Induces Relaxation by Activating Potassium Channels and Blocking Calcium Channels in Isolated Rat Aorta. Molecules 2019; 24:molecules24152748. [PMID: 31362388 PMCID: PMC6695676 DOI: 10.3390/molecules24152748] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [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: 04/11/2019] [Revised: 05/08/2019] [Accepted: 05/11/2019] [Indexed: 11/16/2022] Open
Abstract
Alkaloids derived from plants have shown great medicinal benefits, and are often reported for their use in cardiovascular disease management. Aristotelia chilensis (Molina) Stuntz (Maqui) has shown important medicinal properties in traditional useage. In this study, we evaluated the effect of the indole-alkaloid aristoteline (ARI), isolated from leaves of Maqui, on vascular reactivity of isolated aortic rings from normotensive rats. ARI induced relaxation (100%) in a concentration-dependent manner in intact or denuded-endothelium aortic rings pre-contracted with phenylephrine (PE; 1 μM). However, a specific soluble guanylyl cyclase inhibitor (ODQ; 1 μM) significantly reduced the relaxation to ARI in aortic rings pre-contracted with PE. In the presence of ARI, the contraction induced by KCl or PE was significantly (p < 0.05) decreased. Interestingly, the potassium channel blockade with 10 μM BaCl2 (Kir), 10 μM glibenclamide (KATP), 1 mM tetraethylammonium (TEA; KCa1.1), or 1 mM 4-aminopyridine (4-AP; Kv) significantly (p < 0.05) reduced the ARI-induced relaxation. ARI significantly (p < 0.05) reduced the contractile response to agonist of CaV1.2 channels (Bay K8644; 10 nM), likely reducing the influx of extracellular calcium through plasma membrane. The mechanisms associated with this process suggest an activation of the potassium channels, a calcium-induced antagonism and endothelium independent vasodilation that possibly involves the nitric oxide-independent soluble guanylate cyclase pathway.
Collapse
Affiliation(s)
- Fernando Romero
- Vicerrectoría de Investigación y Postgrado, Programa de Doctorado en Ciencias Médicas, Universidad de la Frontera, Temuco 4780000, Chile.
| | - Javier Palacios
- Laboratorio de Bioquímica Aplicada, Departamento de Química y Farmacia, Facultad Ciencias de la Salud, Universidad Arturo Prat, Iquique 1110939, Chile.
| | - Ignacio Jofré
- Laboratorio de Neurociencias y Biología de Péptidos, Centro de Excelencia en Biotecnología de La Reproducción, Facultad de Medicina, Universidad de La Frontera, Temuco 4811230, Chile
| | - Cristian Paz
- Laboratorio de Productos Naturales y Descubrimiento de Fármacos, Departamento de Ciencias básicas, Universidad de La Frontera, Temuco 4811230, Chile
| | - Chukwuemeka R Nwokocha
- Department of Basic Medical Sciences Physiology Section, Faculty of Medical Sciences, The University of the West Indies, Mona, Kingston 7, KGN, Jamaica (W.I.)
| | - Adrián Paredes
- Laboratorio de Química Biológica, Instituto Antofagasta, Universidad de Antofagasta, Antofagasta 1270300, Chile
| | - Fredi Cifuentes
- Laboratorio de Fisiología Experimental, Instituto Antofagasta, Universidad de Antofagasta, Antofagasta 1270300, Chile
| |
Collapse
|
6
|
Loves S, van Groningen L, Filius M, Mekking M, Brandon T, Tack CJ, Hermus A, de Boer H. High-Dose, Diazoxide-Mediated Insulin Suppression Boosts Weight Loss Induced by Lifestyle Intervention. J Clin Endocrinol Metab 2018; 103:4014-4022. [PMID: 30202851 DOI: 10.1210/jc.2018-01147] [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] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 09/04/2018] [Indexed: 12/26/2022]
Abstract
CONTEXT Obesity-related hyperinsulinism may impede lifestyle-initiated weight loss. OBJECTIVE Proof-of-concept study to investigate the amplifying effects of diazoxide (DZX)-mediated insulin suppression on lifestyle-induced weight loss in nondiabetic, hyperinsulinemic, obese men. DESIGN Twelve-month study comprising an initial 6-month, double-blind trial, followed by a partially de-blinded 6-month extension in men with obesity with a body mass index of 30 to 37.5 kg/m2 and a fasting serum C-peptide level >1.00 nM. Patients were randomized into three treatment groups: DZX + placebo (DZX + PL), DZX + metformin (DZX + MTF), and double PL (PL + PL). RESULTS At 6 months, DZX treatment was associated with a 6.1-kg PL-subtracted decline in fat mass (FM), and at 12 months, FM had decreased by a total of 15.7 ± 2.5 kg. Twelve months of DZX treatment was also associated with a significant decline in systolic (-6.6%) and diastolic (-8.6%) blood pressure and low-density lipoprotein-cholesterol (-18%) and triglycerides (-43%) and a 39% rise in high-density lipoprotein-cholesterol. These effects were achieved at the cost of a small rise in fasting glucose (95% CI: 0.2 to 1.0 mM) and hemoglobin A1c (95% CI: -0.08% to 0.44%). There were no differences between DZX monotherapy and the combination of DZX + MTF. CONCLUSION High-dose DZX treatment of 1 year resulted in a substantial decrease in FM, blood pressure, and lipid levels at the cost of a small rise in blood glucose levels.
Collapse
Affiliation(s)
- Sandra Loves
- Department of Internal Medicine, Rijnstate Hospital, AD Arnhem, Netherlands
| | | | - Margreet Filius
- Department of Clinical Pharmacy, Rijnstate Hospital, AD Arnhem, Netherlands
| | - Marja Mekking
- Department of Clinical Chemistry, Rijnstate Hospital, AD Arnhem, Netherlands
| | - Tom Brandon
- Department of Sports Medicine, Rijnstate Hospital, AD Arnhem, Netherlands
| | - Cees J Tack
- Department of Internal Medicine, Radboud University, Nijmegen Medical Centre, GA Nijmegen, Netherlands
| | - Ad Hermus
- Department of Internal Medicine, Radboud University, Nijmegen Medical Centre, GA Nijmegen, Netherlands
| | - Hans de Boer
- Department of Internal Medicine, Rijnstate Hospital, AD Arnhem, Netherlands
| |
Collapse
|
7
|
Guven C. The effect of Diazoxide on norepinephrine-induced cardiac hypertrophy, in vitro. Cell Mol Biol (Noisy-le-grand) 2018; 64:50-54. [PMID: 30084794] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 07/04/2018] [Accepted: 07/09/2018] [Indexed: 06/08/2023]
Abstract
Cardiac hypertrophy is associated with mitochondrial dysfunctions, which leads to heart failure if sustained. The aim of present study is to test hypothesis whether activation of mitochondrial KATP channel (mitoKATP) by diazoxide improve mitochondrial membrane potential (MMP) and oxidative stress in an in vitro model of cardiac hypertrophy. Rat cardiomyocytes cell line (H9c2) was used to create four groups as control, diazoxide, hypertrophy, hypertrophy and diazoxide. Norepinephrine was used to induce hypertrophy. Diazoxide and norepinephrine were simultaneously administered. After 24 hours treatment, total oxidant status (TOS), total antioxidant status (TAS) and superoxide dismutase (SOD) activities were measured. MMP and F-actin distribution were analyzed. Hypertrophy significantly elevated TOS level. In addition, diazoxide administration significantly increased TOS level in the normal cell line. There were no significant differences in SOD activity, TAS and oxidative stress index (OSI) between groups. Hypertrophy caused a decrease in MMP and destrupted F-actin. Diazoxide improved MMP and F-actin in mitochondria. Hypertrophy impaired the function and structure of mitochondria. The opening of mitoKATP by diazoxide failed to improve oxidative stress; however, it is effective against mitochondrial damage caused by hypertrophy.
Collapse
Affiliation(s)
- Celal Guven
- The Department of Biophysics, Faculty of Medicine, Nigde Omer Halisdemir University, Nigde, Turkey
| |
Collapse
|
8
|
Siddiqui S, Hassan S, Imran S, Khan F, Ahmed F, Dar A. Cardamom extract induces cell proliferation by increasing potassium currents in NIH3T3 cell line. Pak J Pharm Sci 2017; 30:2211-2215. [PMID: 29175791] [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: 06/07/2023]
Abstract
Amommum subulatum (Roxb.) or Cardamom extract is known to have anti-inflammatory and neuroprotective effects towards many gastrointestinal related problems. However, uptill now different fractions of cardamom extract on fibroblasts with respect to potassium channel activity have not been investigated. Therefore, present study investigated the effects of different fractions of cardamom extract on potassium channels in non-tumor NIH3T3 cell line. Phytochemical analysis of hydroalcoholic, n-hexane, butane and ethyl acetate fractions of cardamom extracts were purified and isolated by thin layer chromatography (TLC). 3T3 cells were cultured and incubated with hydroalcohol (1-2 μ/ml), n-hexane (1 μ/ml), butane (2 μ/ml) and ethyl acetate (1-2 μ/ml) for 5 hrs at 37°C. Modulation in potassium currents were recorded by whole-cell patch clamp method. The data showed two constituents Cineol (C10H18O) and Terpinyl acetate (C10H17OOCCH3) by TLC method. The present study shows that the constituents in n-hexane, hydro alcohol (1 μ/ml) and ethyl acetate (2 μ/ml) significantly increased (p<0.01) the potassium outward rectifying currents from NIH3T3 cells when compared to untreated controls cells. Whereas, butanol fraction (2 μ/ml) significantly decreased (p<0.01) the inward rectifying currents when compared to controls. Moreover hydroalcoholic and n-hexane fractions have increased the proliferation in 3T3 cell line. On the other hand butanol and ethyl acetate did not induce proliferation in 3T3 cells. Taken together, our data suggested that cardamom extract contains constituents that increased K+ currents, cell migration and proliferation and are involved in wound healing.
Collapse
Affiliation(s)
- Sonia Siddiqui
- Department of Neuroscience, Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan
| | - Sohail Hassan
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy & Pharmaceutical Sciences, University of Karachi, Karachi, Pakistan
| | - Sumaira Imran
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy & Pharmaceutical Sciences, University of Karachi, Karachi, Pakistan
| | - Faisal Khan
- Department of Neuroscience, Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan
| | - Faheem Ahmed
- Herbion Pakistan (Private) Limited, Karachi, Pakistan
| | - Asim Dar
- Jinnah Sind Medical University, Karachi, Pakistan
| |
Collapse
|
9
|
Liang W, Chen M, Zheng D, Li J, Song M, Zhang W, Feng J, Lan J. The Opening of ATP-Sensitive K+ Channels Protects H9c2 Cardiac Cells Against the High Glucose-Induced Injury and Inflammation by Inhibiting the ROS-TLR4-Necroptosis Pathway. Cell Physiol Biochem 2017; 41:1020-1034. [PMID: 28291959 DOI: 10.1159/000461391] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 12/29/2016] [Indexed: 12/16/2023] Open
Abstract
BACKGROUND/AIMS Hyperglycemia activates multiple signaling molecules, including reactive oxygen species (ROS), toll-like receptor 4 (TLR4), receptor-interacting protein 3 (RIP3, a kinase promoting necroptosis), which mediate hyperglycemia-induced cardiac injury. This study explored whether inhibition of ROS-TLR4-necroptosis pathway contributed to the protection of ATP-sensitive K+ (KATP) channel opening against high glucose-induced cardiac injury and inflammation. METHODS H9c2 cardiac cells were treated with 35 mM glucose (HG) to establish a model of HG-induced insults. The expression of RIP3 and TLR4 were tested by western blot. Generation of ROS, cell viability, mitochondrial membrane potential (MMP) and secretion of inflammatory cytokines were measured as injury indexes. RESULTS HG increased the expression of TLR4 and RIP3. Necrostatin-1 (Nec-1, an inhibitor of necroptosis) or TAK-242 (an inhibitor of TLR4) co-treatment attenuated HG-induced up-regulation of RIP3. Diazoxide (DZ, a mitochondrial KATP channel opener) or pinacidil (Pin, a non-selective KATP channel opener) or N-acetyl-L-cysteine (NAC, a ROS scavenger) pre-treatment blocked the up-regulation of TLR4 and RIP3. Furthermore, pre-treatment with DZ or Pin or NAC, or co-treatment with TAK-242 or Nec-1 attenuated HG-induced a decrease in cell viability, and increases in ROS generation, MMP loss and inflammatory cytokines secretion. However, 5-hydroxy decanoic acid (5-HD, a mitochondrial KATP channel blocker) or glibenclamide (Gli, a non-selective KATP channel blocker) pre-treatment did not aggravate HG-induced injury and inflammation. CONCLUSION KATP channel opening protects H9c2 cells against HG-induced injury and inflammation by inhibiting ROS-TLR4-necroptosis pathway.
Collapse
|
10
|
Filatova TS, Naumenko N, Galenko-Yaroshevsky PA, Abramochkin DV. M3 cholinoreceptors alter electrical activity of rat left atrium via suppression of L-type Ca 2+ current without affecting K + conductance. J Physiol Biochem 2016; 73:167-174. [PMID: 27858307 DOI: 10.1007/s13105-016-0538-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [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: 08/19/2016] [Accepted: 11/09/2016] [Indexed: 11/28/2022]
Abstract
Electrophysiological effects produced by selective activation of M3 cholinoreceptors were studied in isolated left atrium preparations from rat using the standard sharp glass microelectrode technique. The stimulation of M3 receptors was obtained by application of muscarinic agonist pilocarpine (10-5 M) in the presence of selective M2 antagonist methoctramine (10-7 M). Stimulation of M3 receptors induced marked reduction of action potential duration by 14.4 ± 2.4% and 16.1 ± 2.5% of control duration measured at 50 and 90% of repolarization, respectively. This effect was completely abolished by selective M3 blocker 4-DAMP (10-8 M). In isolated myocytes obtained from the rat left atrium, similar pharmacological stimulation of M3 receptors led to suppression of peak L-type calcium current by 13.9 ± 2.6% of control amplitude (measured at +10 mV), but failed to affect K+ currents I to, I Kur, and I Kir. In the absence of M2 blocker methoctramine, pilocarpine (10-5 M) produced stronger attenuation of I CaL and induced an increase in I Kir. This additive inward rectifier current could be abolished by highly selective blocker of Kir3.1/3.4 channels tertiapin-Q (10-6 M) and therefore was identified as I KACh. Thus, in the rat atrial myocardium activation of M3 receptors leads to shortening of action potentials via suppression of I CaL, but does not enhance the major potassium currents involved in repolarization. Joint stimulation of M2 and M3 receptors produces stronger action potential shortening due to M2-mediated activation of I KACh.
Collapse
MESH Headings
- Action Potentials/drug effects
- Animals
- Animals, Outbred Strains
- Calcium Channels, L-Type/chemistry
- Calcium Channels, L-Type/metabolism
- Cardiovascular Agents/pharmacology
- Cells, Cultured
- Down-Regulation/drug effects
- Electrophysiological Phenomena/drug effects
- Escin/pharmacology
- Heart Atria/cytology
- Heart Atria/drug effects
- Heart Atria/metabolism
- In Vitro Techniques
- Mice
- Microelectrodes
- Muscarinic Agonists/pharmacology
- Muscarinic Antagonists/pharmacology
- Patch-Clamp Techniques
- Potassium Channel Blockers/pharmacology
- Potassium Channels/agonists
- Potassium Channels/metabolism
- Potassium Channels, Inwardly Rectifying/agonists
- Potassium Channels, Inwardly Rectifying/antagonists & inhibitors
- Potassium Channels, Inwardly Rectifying/metabolism
- Rats
- Receptor, Muscarinic M3/agonists
- Receptor, Muscarinic M3/antagonists & inhibitors
- Receptor, Muscarinic M3/metabolism
Collapse
Affiliation(s)
- Tatiana S Filatova
- Department of Human and Animal Physiology, Biological Faculty of the Moscow State University, Leninskiye Gory, 1, 12, Moscow, Russia
| | - Nikolay Naumenko
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | | | - Denis V Abramochkin
- Department of Human and Animal Physiology, Biological Faculty of the Moscow State University, Leninskiye Gory, 1, 12, Moscow, Russia.
- Department of Physiology, Pirogov Russian National Research Medical University, Ostrovityanova street, 1, Moscow, Russia.
| |
Collapse
|
11
|
LI QINGLIN, YAN XIAOPEI, KONG HUI, XIE WEIPING, WANG HONG. Iptakalim influences the proliferation and apoptosis of human pulmonary artery smooth muscle cells. Mol Med Rep 2016; 14:715-20. [PMID: 27221642 PMCID: PMC4918544 DOI: 10.3892/mmr.2016.5333] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 05/23/2016] [Indexed: 12/19/2022] Open
Abstract
The aim of the present study was to determine the effect of an ATP-sensitive K+ (KATP) channel opener iptakalim (IPT) on the proliferation and apoptosis of human pulmonary artery smooth muscle cells (HPASMCs), and examine the potential value of IPT to hypoxic pulmonary hyper-tension (HPH) at a cellular level. HPASMCs were divided into the control, ET-1, ET-1+IPT and ET-1+IPT+glibenclamide (GLI) groups. GLI was administered 30 min prior to ET-1 and IPT. The 4 groups were incubated with corresponding reagents for 24 h. Cell viability was evaluated using a CCK-8 assay, cell proliferation by 5-ethynyl-2'-deoxyuridine (EdU) incorporation assay, and cell apoptosis via the expression of apoptosis-related proteins, i.e., Bcl-2-associated X protein (Bax) and B-cell lymphoma 2 (Bcl-2) using western blotting. We incubated HPASMCs with varying concentrations of ET-1 for 24, 48 and 72 h, and found that cell survival rate was increased in a dose-dependent manner (P<0.05) rather than in a time-dependent manner (P>0.05). After co-incubation of HPASMCs with varying concentrations of IPT and ET-1 for 24 h, the cell survival rate was decreased in a dose-dependent manner. The cell survival rate in the IPT+ET-1 group was significantly lower than that in the ET-1 group (P<0.05). The cell viability (P<0.05) and proliferation (P<0.05) in the ET-1 group were higher than those in the control group, and the expression of Bax/Bcl-2 was lower than the control group (P<0.05). The cell viability (P<0.05) and proliferation (P<0.05) in the ET-1+IPT group were lower than those in the ET-1 group, and the expression of Bax/Bcl-2 was higher than that in the ET-1 group (P<0.05). The cell viability (P<0.05) and proliferation (P<0.05) in the ET-1+IPT+GLI group were higher than those in the ET-1+IPT group, and the expression of Bax/Bcl-2 was lower than that in the ET-1+IPT group (P<0.05). In conclusion, IPT inhibited ET-1‑induced HPASMC proliferation and promoted cell apoptosis. Thus, it may play an important role in the treatment of HPH.
Collapse
Affiliation(s)
- QINGLIN LI
- Department of Respiratory Medicine, The First Affiliated Clinical Medical College of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - XIAOPEI YAN
- Department of Respiratory Medicine, The First Affiliated Clinical Medical College of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - HUI KONG
- Department of Respiratory Medicine, The First Affiliated Clinical Medical College of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - WEIPING XIE
- Department of Respiratory Medicine, The First Affiliated Clinical Medical College of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - HONG WANG
- Department of Respiratory Medicine, The First Affiliated Clinical Medical College of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| |
Collapse
|
12
|
Abstract
The purpose of this study was to investigate the cardio-protective effects of nicorandil, an opener of potassium channels, on senile rat hearts from ischemic reperfusion injury. A modified working model of isolated perfused hearts of senile rats was used. After isolation, the hearts underwent 60 min of global hypothermic ischemia treatment, followed by 30 min of reperfusion. These hearts were distributed into three groups, each receiving different cardioplegic solutions: (1) St. Thomas’ solution (Group S), (2) 100 μmol/L nicorandil (Group N), (3) St. Thomas’ solution combined with 100 μmol/L nicorandil (Group S+N). The pre- and post-ischemic myocardial function were assessed by the percentage recovery of the heart rate (HR), ±dp/dtmax (maximal rate of change of left ventricular pressure) and cardiac output (CO). Upon reperfusion, the cardioplegic solution was collected from the coronary sinus and tested for lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB) activity. During 30 min of reperfusion, the percentage recovery of HR, +dp/dt and left ventricular stroke work (LVSW) were significantly higher in Group S+N than in Group S and Group N ( p < 0.05). The percentage of recovery in CO was higher in Group N and Group S+N than in Group S. The electrical activities arresting time (EAT) and mechanical activities arresting time (MAT) were longer in Group N than in Group S and Group N+S( p < 0.01). There were no statistical significance between Group S and Group N+ S( p > 0.05). There were no significant differences in the levels of LDH and CK-MB. Electron microscopic examination revealed better preservation of the ultra-structures of the myocardial tissue in Group N+S than the other two groups. These results indicate that nicorandil combined with St. Thomas’ solution can improve the left ventricular function of the post-ischemic senile rat and offer a better myocardial protective effect on the ischemic senile myocardium.
Collapse
Affiliation(s)
- Jinping Liu
- Departament of Cardiopulmonary Bypass, Cardiovascular Institute and Fuwai Hospital, Beijing, China.
| | | | | | | | | |
Collapse
|
13
|
Abstract
Endothelial cell dysfunction is the primary cause of microvascular complications in diabetes. Diazoxide enables beta cells to rest by reversibly suppressing glucose-induced insulin secretion by opening ATP-sensitive K+ channels in the beta cells. This study investigated the role of diazoxide in wound healing in mice with streptozotocin (STZ)-induced diabetes and explored the possible mechanisms of its effect. Compared to the controls, mice with STZ-induced diabetes exhibited significantly impaired wound healing. Diazoxide treatment (30 mg/kg/d, intragastrically) for 28 days accelerated wound closure and stimulated angiogenesis in the diabetic mice. Circulating endothelial progenitor cells (EPCs) increased significantly in the diazoxide-treated diabetic mice. The adhesion, migration, and tube formation abilities of bone marrow (BM)-EPCs were impaired by diabetes, and these impairments were improved by diazoxide treatment. The expression of both p53 and TSP-1 increased in diabetic mice compared to that in the controls, and these increases were inhibited significantly by diazoxide treatment. In vitro, diazoxide treatment improved the impaired BM-EPC function and diminished the increased expression of p53 and TSP-1 in cultured BM-EPCs caused by high glucose levels. We conclude that diazoxide improved BM-EPC function in mice with STZ-induced diabetes, possibly via a p53- and TSP-1-dependent pathway.
Collapse
Affiliation(s)
- Zhang-Peng Li
- Department of Pharmacology, School of Pharmacy, Second Military Medical University, Shanghai 200433, China
| | - Ru-Juan Xin
- Department of Pharmacology, School of Pharmacy, Second Military Medical University, Shanghai 200433, China
| | - Hong Yang
- Department of Pharmacology, School of Pharmacy, Second Military Medical University, Shanghai 200433, China
| | - Guo-Jun Jiang
- Department of Pharmacy, Zhejiang Xiaoshan Hospital, Zhejiang 311202, China
| | - Ya-Ping Deng
- Department of Pharmacy, Zhejiang Xiaoshan Hospital, Zhejiang 311202, China
| | - Dong-Jie Li
- Department of Pharmacy, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, China
| | - Fu-Ming Shen
- Department of Pharmacology, School of Pharmacy, Second Military Medical University, Shanghai 200433, China and Department of Pharmacy, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, China,
| |
Collapse
|
14
|
Mohamed MSA. Ascorbic Acid Supplementation During Ex Vivo Lung Perfusion. EXP CLIN TRANSPLANT 2016; 14:112-113. [PMID: 26862827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Affiliation(s)
- Mohamed S A Mohamed
- From the University of Cologne, Deutz-Kalker Str. 118, 50679, Cologne, Germany
| |
Collapse
|
15
|
Bu HM, Yang CY, Wang ML, Ma HJ, Sun H, Zhang Y. K(ATP) channels and MPTP are involved in the cardioprotection bestowed by chronic intermittent hypobaric hypoxia in the developing rat. J Physiol Sci 2015; 65:367-76. [PMID: 25862574 PMCID: PMC10717084 DOI: 10.1007/s12576-015-0376-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [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: 10/14/2014] [Accepted: 03/18/2015] [Indexed: 10/23/2022]
Abstract
The aim of this study was to explore the mechanism underlying the cardioprotection bestowed by chronic intermittent hypobaric hypoxia (CIHH) against ischemia/reperfusion (I/R) injury in developing rats. Neonatal male rats were subjected to CIHH treatments that simulated an altitude of 3000 m a.s.l. for 28 days (CIHH28) and 42 days (CIHH42), respectively, or no treatment (control). The left ventricular function of isolated hearts was evaluated. The ultra-microstructure, superoxide dismutase (SOD) activity and total anti-oxidation capacity (TAC) of the myocardium were determined. The basic left ventricular function remained unchanged in CIHH rats, except for an increased coronary flow. The recovery of cardiac function from I/R, however, was much better in CIHH rats than in control rats. Compared to control rats, CIHH rats had much higher SOD levels and TAC, and the ultra-microstructure damage to mitochondria was considerably less. The cardiac protection of CIHH was canceled out by glibenclamide, an inhibitor of the ATP-sensitive potassium (K(ATP)) channel, 5-hydroxydecanoate, an inhibitor of mitochondrial K(ATP) (mitoKATP), and atractyloside, an opener of the mitochondrial permeability transition pore (MPTP). To the contrary, diazoxide, an opener of mitoKATP, and cyclosporin A, a blocker of MPTP opening, induced cardioprotection in control rats. These results suggest that CIHH protects the heart against I/R injury in developing rats through opening of the K(ATP) channel and inhibiting of opening of the MPTP.
Collapse
Affiliation(s)
- Hui-min Bu
- Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 China
- Department of Physiology, Xuzhou Medical College, Xuzhou, 221004 China
| | - Chang-ying Yang
- Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 China
| | - Mei-ling Wang
- Electrophysiological Department, Central Hospital of Cangzhou, Cangzhou, 061001 China
| | - Hui-jie Ma
- Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 China
- Hebei Collaborative Innovation Center for Cardio-cerebrovascular Disease, Shijiazhuang, 050000 China
| | - Hong Sun
- Department of Physiology, Xuzhou Medical College, Xuzhou, 221004 China
| | - Yi Zhang
- Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 China
- Hebei Collaborative Innovation Center for Cardio-cerebrovascular Disease, Shijiazhuang, 050000 China
| |
Collapse
|
16
|
Karabacak K, Kaya E, Ulusoy KG, Seyrek M, Kurtoglu M, Doganci S, Yildirim V, Yildiz O, Demirkilic U. Effects of taurine on contractions of human internal mammary artery: a potassium channel opening action. Eur Rev Med Pharmacol Sci 2015; 19:1498-1504. [PMID: 25967726] [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: 06/04/2023]
Abstract
OBJECTIVE Taurine is an abundant amino acid that is widely distributed in human and animal tissues. Pharmacodynamic studies show that taurine has hypotensive and myocardial protective effects. Studies in isolated tissue baths show that taurine relaxes precontracted arteries. This study aimed to show the effects of taurine on human internal mammary artery (IMA) in vitro and to explain the mechanisms of its effects. METHODS The response in the IMA was recorded isometrically by a force displacement transducer in isolated organ baths. Taurine (20, 40, 80 mM) was added to organ baths after precontraction with KCl (45 mM) or serotonin (5-HT, 30 µM). Taurine-induced relaxations were also tested in the presence of the cyclooxygenase inhibitor indomethacin (10 µM), the nitric oxide synthase inhibitor L-NAME (100 µM), the large conductance Ca2+-activated K+ channel inhibitor tetraethylammonium (TEA, 1 mM), the ATP-sensitive K+ channel inhibitor glibenclamide (GLI, 10 µM), the voltage-sensitive K+ channel inhibitor 4-aminopyridine (4-AP, 1 mM) and the inward rectifier K+ channel inhibitor barium chloride (BaCl2, 30 µM). RESULTS Taurine did not affect the resting tone of IMA. However, it produced relaxation in the 5-HT and KCl -precontracted preparations. The relaxation to IMA was not affected by GLI, 4-AP, BaCl2, indomethacin and L-NAME. But, TEA inhibited taurine -induced relaxations significantly (p < 0.05). CONCLUSIONS The preincubation of IMA with taurine antagonized KCl and 5-HT induced contractions in a concentration dependent manner, while it did not affect the resting tone. The relaxations to taurine were significantly antagonized by pretreatment with TEA. These results suggest that mechanism of vasodilator effect of taurine in IMA may be the activation of large conductance Ca2+-activated K+ channels.
Collapse
Affiliation(s)
- K Karabacak
- Department of Cardiovascular Surgery, Gulhane Faculty of Medicine, Ankara, Turkey.
| | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Yang C, Zhang SS, Li XL, Wang ZF, Zhao LQ. Inhibitory effect of TongXie-YaoFang formula on colonic contraction in rats. World J Gastroenterol 2015; 21:2912-2917. [PMID: 25780288 PMCID: PMC4356910 DOI: 10.3748/wjg.v21.i10.2912] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 09/20/2014] [Accepted: 12/01/2014] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the pharmacological effect of TongXie-YaoFang (TXYF) formula and its underlying mechanisms.
METHODS: A neonatal maternal separation plus restraint stress (NMS + RS) model of diarrhea-predominant irritable bowel syndrome was developed by subjecting male Sprague-Dawley rats to daily maternal separation from postnatal days 2 to 21 plus restraint stress from days 50 to 59. Rats were randomly divided into two groups (NMS + RS and TXYF formula), and rats with no handling or separation were used as normal controls. Starting from postnatal day 60, rats were administered TXYF formula (9.84 g/100 g body weight) orally twice daily for 14 consecutive days, while the normal and NMS + RS groups were given distilled water. The distinctions of movement index (MI, area under the curve of contraction intensity/min, mg/min) and contraction frequency (CF, number of contractions/min, times/min) of isolated colonic longitudinal smooth muscle strips (CLSMs) in the three groups before and after treatment were observed with a Power Lab system. Different inhibitors were applied, and then 10-4 mol/L acetylcholine chloride (Ach) was added to CLSMs to induce muscle contraction.
RESULTS: Before treatment, the MI of CLSMs in the NMS + RS and TXYF formula groups was similar and both higher than that in the normal group (545.49 ± 73.66 mg/min vs 245.76 ± 34.44 mg/min and 551.09 ± 54.29 mg/min vs 245.76 ± 34.44 mg/min, P < 0.01, respectively). After treatment, the MI in the TXYF formula group was lower than that in the NMS + RS group (261.39 ± 38.59 mg/min vs 533.9 ± 61.63 mg/min, P < 0.01). In the same way, the CF of CLSMs in the NMS + RS and TXYF formula groups was similar and both higher than that in the normal group (3.42 ± 0.25 times/min and 3.31 ± 0.21 vs 1.1 ± 0.17 times/min, P < 0.01) before treatment. After treatment, the CF in the TXYF formula group was lower than that in the NMS + RS group (1.42 ± 0.87 times/min vs 3.11 ± 0.82 times/min, P < 0.01) and similar to that in the normal group (1.42 ± 0.87 times/min vs 1.09 ± 0.13 times/min). When 8-(N,N-diethylamino)octyl 3,4,5-trimethoxybenzoate hydrochloride and 4-aminopyridine were added to the bath and equilibrated for 30 min, respectively, and 10-4 mol/L Ach was added to CLSMs to induce muscle contraction, MI of the CLSMs in the TXYF formula group was lower than that in the normal group (666 ± 36.32 mg/min vs 747.77 ± 49.47 mg/min, and 686.53 ± 39.17 mg/min vs 750.45 ± 29.39 mg/min; P < 0.01, respectively). The MI of CLSMs in the TXYF formula group was lower than that in the normal group after treatment with nifedipine (689.48 ± 30.84 mg/min vs 741.65 ± 32.41 mg/min; P < 0.05).
CONCLUSION: TXYF formula inhibits colon contraction in rats. This may be related to activation of specific potassium channels and inhibition of extracellular calcium internal flow.
Collapse
|
18
|
Sunaga D, Tanno M, Kuno A, Ishikawa S, Ogasawara M, Yano T, Miki T, Miura T. Accelerated recovery of mitochondrial membrane potential by GSK-3β inactivation affords cardiomyocytes protection from oxidant-induced necrosis. PLoS One 2014; 9:e112529. [PMID: 25390651 PMCID: PMC4229200 DOI: 10.1371/journal.pone.0112529] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [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: 07/21/2014] [Accepted: 10/06/2014] [Indexed: 12/20/2022] Open
Abstract
Loss of mitochondrial membrane potential (ΔΨm) is known to be closely linked to cell death by various insults. However, whether acceleration of the ΔΨm recovery process prevents cell necrosis remains unclear. Here we examined the hypothesis that facilitated recovery of ΔΨm contributes to cytoprotection afforded by activation of the mitochondrial ATP-sensitive K+ (mKATP) channel or inactivation of glycogen synthase kinase-3β (GSK-3β). ΔΨm of H9c2 cells was determined by tetramethylrhodamine ethyl ester (TMRE) before or after 1-h exposure to antimycin A (AA), an inducer of reactive oxygen species (ROS) production at complex III. Opening of the mitochondrial permeability transition pore (mPTP) was determined by mitochondrial loading of calcein. AA reduced ΔΨm to 15±1% of the baseline and induced calcein leak from mitochondria. ΔΨm was recovered to 51±3% of the baseline and calcein-loadable mitochondria was 6±1% of the control at 1 h after washout of AA. mKATP channel openers improved the ΔΨm recovery and mitochondrial calcein to 73±2% and 30±7%, respectively, without change in ΔΨm during AA treatment. Activation of the mKATP channel induced inhibitory phosphorylation of GSK-3β and suppressed ROS production, LDH release and apoptosis after AA washout. Knockdown of GSK-3β and pharmacological inhibition of GSK-3β mimicked the effects of mKATP channel activation. ROS scavengers administered at the time of AA removal also improved recovery of ΔΨm. These results indicate that inactivation of GSK-3β directly or indirectly by mKATP channel activation facilitates recovery of ΔΨm by suppressing ROS production and mPTP opening, leading to cytoprotection from oxidant stress-induced cell death.
Collapse
Affiliation(s)
- Daisuke Sunaga
- Department of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Masaya Tanno
- Department of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Atsushi Kuno
- Department of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Satoko Ishikawa
- Department of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Makoto Ogasawara
- Department of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Toshiyuki Yano
- Department of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Takayuki Miki
- Department of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Tetsuji Miura
- Department of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan
- * E-mail:
| |
Collapse
|
19
|
Nogueira MA, Coelho AMM, Sampietre SN, Patzina RA, Pinheiro da Silva F, D'Albuquerque LAC, Machado MCC. Beneficial effects of adenosine triphosphate-sensitive K + channel opener on liver ischemia/reperfusion injury. World J Gastroenterol 2014; 20:15319-15326. [PMID: 25386080 PMCID: PMC4223265 DOI: 10.3748/wjg.v20.i41.15319] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 05/28/2014] [Accepted: 07/11/2014] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the effect of diazoxide administration on liver ischemia/reperfusion injury.
METHODS: Wistar male rats underwent partial liver ischemia performed by clamping the pedicle from the medium and left anterior lateral segments for 1 h under mechanical ventilation. They were divided into 3 groups: Control Group, rats submitted to liver manipulation, Saline Group, rats received saline, and Diazoxide Group, rats received intravenous injection diazoxide (3.5 mg/kg) 15 min before liver reperfusion. 4 h and 24 h after reperfusion, blood was collected for determination of aspartate transaminase (AST), alanine transaminase (ALT), tumor necrosis factor (TNF-α), interleukin-6 (IL-6), interleukin-10 (IL-10), nitrite/nitrate, creatinine and tumor growth factor-β1 (TGF-β1). Liver tissues were assembled for mitochondrial oxidation and phosphorylation, malondialdehyde (MDA) content, and histologic analysis. Pulmonary vascular permeability and myeloperoxidase (MPO) were also determined.
RESULTS: Four hours after reperfusion the diazoxide group presented with significant reduction of AST (2009 ± 257 U/L vs 3523 ± 424 U/L, P = 0.005); ALT (1794 ± 295 U/L vs 3316 ± 413 U/L, P = 0.005); TNF-α (17 ± 9 pg/mL vs 152 ± 43 pg/mL, P = 0.013; IL-6 (62 ± 18 pg/mL vs 281 ± 92 pg/mL); IL-10 (40 ± 9 pg/mL vs 78 ± 10 pg/mL P = 0.03), and nitrite/nitrate (3.8 ± 0.9 μmol/L vs 10.2 ± 2.4 μmol/L, P = 0.025) when compared to the saline group. A significant reduction in liver mitochondrial dysfunction was observed in the diazoxide group compared to the saline group (P < 0.05). No differences in liver MDA content, serum creatinine, pulmonary vascular permeability and MPO activity were observed between groups. Twenty four hours after reperfusion the diazoxide group showed a reduction of AST (495 ± 78 U/L vs 978 ± 192 U/L, P = 0.032); ALT (335 ± 59 U/L vs 742 ± 182 U/L, P = 0.048), and TGF-β1 (11 ± 1 ng/mL vs 17 ± 0.5 ng/mL, P = 0.004) serum levels when compared to the saline group. The control group did not present alterations when compared to the diazoxide and saline groups.
CONCLUSION: Diazoxide maintains liver mitochondrial function, increases liver tolerance to ischemia/reperfusion injury, and reduces the systemic inflammatory response. These effects require further evaluation for using in a clinical setting.
Collapse
|
20
|
Trechot P. Targeting solid tumours with potassium channel activators. A return to fundamentals? Therapie 2014; 69:533-4. [PMID: 25371295 DOI: 10.2515/therapie/2014208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 09/24/2014] [Indexed: 11/20/2022]
Abstract
From a pharmacological point of view nicotinamide and minoxidil are potassium channel activators. Nicotinamide is used as a radiosensitizer in ARCON (accelerated radiotherapy combined with carbogen breathing and nicotinamide) therapeutic strategy with promising results but not confirmed so far. Minoxidil has never been considered by radiotherapists. Based from recent pathophysiological considerations we suggest a new perspective for the use of these two "old" molecules in order to target solid tumours.
Collapse
|
21
|
Tregub PP, Kulikov VP, Stepanova LA, Zabrodina AS, Nagibaeva ME. [The role of adenosine Al receptors and mitochondrial K+ATP channels in the mechanism of increasing the resistance to acute hypoxia in the combined effects of hypoxia and hypercapnia]. Patol Fiziol Eksp Ter 2014:48-52. [PMID: 25980226] [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: 06/04/2023]
Abstract
We studied the role of the role of mitoK+ATp channels and Al-adenosine receptor in the mechanism of increasing the resistance to acute hypoxia after hypoxic, hypercapnic and hypercapnic-hypoxic preconditioning. It is shown that mitochondrial ATP-sensitive potassium channels and Al-adenosine receptors, an important mechanism of preconditioning have a high value to increase the resistance to acute hypoxia/ischemia in the combined effect of hypoxia and hypercapnia. However, with regard to the adenosine receptor, this mechanism is realized without the participation hypercapnic component, which apparently starts neuroprotection without activation of the adenosine Al receptors.
Collapse
|
22
|
Bruner JK, Zou B, Zhang H, Zhang Y, Schmidt K, Li M. Identification of novel small molecule modulators of K2P18.1 two-pore potassium channel. Eur J Pharmacol 2014; 740:603-10. [PMID: 24972239 DOI: 10.1016/j.ejphar.2014.06.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [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: 01/30/2014] [Revised: 06/11/2014] [Accepted: 06/17/2014] [Indexed: 11/19/2022]
Abstract
Two-pore domain potassium (K2P) channels are responsible for background potassium (K+) current, which is crucial for the maintenance of resting membrane potential. K2P18.1, also called TWIK-related spinal cord K+ channel (TRESK) or KCNK18, is thought to be a major contributor to background K+ currents, particularly in sensory neurons where it is abundantly expressed. Despite its critical role and potential therapeutic implication, pharmacological tools for probing K2P18.1 activity remain unavailable. Here, we report a high-throughput screen against a collection of bioactive compounds that yielded 26 inhibitors and 8 activators of K2P18.1 channel activity with more than 10-fold selectivity over the homologous channel K2P9.1. Among these modulators, the antihistamine loratadine inhibited K2P18.1 activity with IC50 of 0.49±0.23 µM and is considerably more potent than existing K2P18.1 inhibitors. Importantly, the inhibition by loratadine remains equally efficacious upon potentiation of K2P18.1 by calcium signaling. Furthermore, the loratadine effect is dependent on transmembrane residues F145 and F352, providing orthogonal evidence that the inhibition is caused by a direct compound-channel interaction. This study reveals new pharmacological modulators of K2P18.1 activity useful in dissecting native K2P18.1 function.
Collapse
Affiliation(s)
- J Kyle Bruner
- The Solomon H. Snyder Department of Neuroscience, High Throughput Biology Center, Johns Hopkins University, Baltimore, MD 21205, USA; Johns Hopkins Ion Channel Center (JHICC), Johns Hopkins University, Baltimore, MD 21205, USA
| | - Beiyan Zou
- The Solomon H. Snyder Department of Neuroscience, High Throughput Biology Center, Johns Hopkins University, Baltimore, MD 21205, USA; Johns Hopkins Ion Channel Center (JHICC), Johns Hopkins University, Baltimore, MD 21205, USA
| | - Hongkang Zhang
- The Solomon H. Snyder Department of Neuroscience, High Throughput Biology Center, Johns Hopkins University, Baltimore, MD 21205, USA; Johns Hopkins Ion Channel Center (JHICC), Johns Hopkins University, Baltimore, MD 21205, USA
| | - Yixin Zhang
- The Solomon H. Snyder Department of Neuroscience, High Throughput Biology Center, Johns Hopkins University, Baltimore, MD 21205, USA; Johns Hopkins Ion Channel Center (JHICC), Johns Hopkins University, Baltimore, MD 21205, USA
| | - Katharina Schmidt
- Department of Physiology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Min Li
- The Solomon H. Snyder Department of Neuroscience, High Throughput Biology Center, Johns Hopkins University, Baltimore, MD 21205, USA; Johns Hopkins Ion Channel Center (JHICC), Johns Hopkins University, Baltimore, MD 21205, USA.
| |
Collapse
|
23
|
Wu C, V Gopal K, Lukas TJ, Gross GW, Moore EJ. Pharmacodynamics of potassium channel openers in cultured neuronal networks. Eur J Pharmacol 2014; 732:68-75. [PMID: 24681057 DOI: 10.1016/j.ejphar.2014.03.017] [Citation(s) in RCA: 19] [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] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 03/06/2014] [Accepted: 03/17/2014] [Indexed: 12/30/2022]
Abstract
A novel class of drugs - potassium (K(+)) channel openers or activators - has recently been shown to cause anticonvulsive and neuroprotective effects by activating hyperpolarizing K(+) currents, and therefore, may show efficacy for treating tinnitus. This study presents measurements of the modulatory effects of four K(+) channel openers on the spontaneous activity and action potential waveforms of neuronal networks. The networks were derived from mouse embryonic auditory cortices and grown on microelectrode arrays. Pentylenetetrazol was used to create hyperactivity states in the neuronal networks as a first approximation for mimicking tinnitus or tinnitus-like activity. We then compared the pharmacodynamics of the four channel activators, retigabine and flupirtine (voltage-gated K(+) channel KV7 activators), NS1619 and isopimaric acid ("big potassium" BK channel activators). The EC50 of retigabine, flupirtine, NS1619, and isopimaric acid were 8.0, 4.0, 5.8, and 7.8µM, respectively. The reduction of hyperactivity compared to the reference activity was significant. The present results highlight the notion of re-purposing the K(+) channel activators for reducing hyperactivity of spontaneously active auditory networks, serving as a platform for these drugs to show efficacy toward target identification, prevention, as well as treatment of tinnitus.
Collapse
Affiliation(s)
- Calvin Wu
- Department of Speech and Hearing Sciences, University of North Texas, Denton, TX 76203, United States; Department of Biological Sciences, University of North Texas, Denton, TX 76203, United States; Center for Network Neuroscience, University of North Texas, Denton, TX 76203, United States.
| | - Kamakshi V Gopal
- Department of Speech and Hearing Sciences, University of North Texas, Denton, TX 76203, United States; Center for Network Neuroscience, University of North Texas, Denton, TX 76203, United States
| | - Thomas J Lukas
- Department of Molecular Pharmacology and Biological Chemistry, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States
| | - Guenter W Gross
- Department of Biological Sciences, University of North Texas, Denton, TX 76203, United States; Center for Network Neuroscience, University of North Texas, Denton, TX 76203, United States
| | - Ernest J Moore
- Department of Speech and Hearing Sciences, University of North Texas, Denton, TX 76203, United States; Center for Network Neuroscience, University of North Texas, Denton, TX 76203, United States; Department of Molecular Pharmacology and Biological Chemistry, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States
| |
Collapse
|
24
|
Murzaeva SV, Belova SP, Mironova GD. [Determination of the antioxidant properties of activators of mitochondrial ATP-dependent potassium channels with the Amplex Red fluorescent indicator]. ACTA ACUST UNITED AC 2014; 49:345-52. [PMID: 24455859 DOI: 10.7868/s0555109913040107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The effect of adaptogens-antihypoxants that participate in the activation of mitochondrial ATP-dependent potassium channels (mitoK(ATP)) at the oxidation of the Amplex Red (AR) fluorescent indicator in a peroxidase system was tested. It was shown that Extralife, Hypoxen, taurine, and synthetic antioxidant ionol can be arranged in the following row, according to the fluorescence inhibition activity: Extralife > Hypoxen > > ionol > taurine; their effect was shown to be concentration-dependent. The calculated K(i) value of fluorescence indicators demonstrate fast and slow phases of inhibition of the AR oxidation by Extralife and Hypoxen. The fast phase occurs in the presence of microdoses (0.05-3 microg/mL) of adaptogens and is related to the competition for H2O2, which is in agreement with our previous data on the mitoK(ATP) activation by doses of adaptogens related to the H2O2 consumption. The slow phase is characteristic of high adaptogen and ionol concentrations and is related to the competition for phenoxyl radicals of resorufin formed during AR oxidation. The obtained results allow one to suggest the application of a highly sensitive model peroxidase system with AR for the preliminary testing of compounds activating mitoK(ATP) channels.
Collapse
|
25
|
Wright PD, Weir G, Cartland J, Tickle D, Kettleborough C, Cader MZ, Jerman J. Cloxyquin (5-chloroquinolin-8-ol) is an activator of the two-pore domain potassium channel TRESK. Biochem Biophys Res Commun 2013; 441:463-468. [PMID: 24383077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
TRESK is a two-pore domain potassium channel. Loss of function mutations have been linked to typical migraine with aura and due to TRESK’s expression pattern and role in neuronal excitability it represents a promising therapeutic target. We developed a cell based assay using baculovirus transduced U20S cells to screen for activators of TRESK. Using a thallium flux system to measure TRESK channel activity we identified Cloxyquin as a novel activator. Cloxyquin was shown to have an EC50 of 3.8 μM in the thallium assay and displayed good selectivity against other potassium channels tested. Activity was confirmed using whole cell patch electrophysiology, with Cloxyquin causing a near two fold increase in outward current. The strategy presented here will be used to screen larger compound libraries with the aim of identifying novel chemical series which may be developed into new migraine prophylactics.
Collapse
|
26
|
Owolabi OJ, Omogbai EKI. Evaluation of the potassium channel activator levcromakalim (BRL38227) on the lipid profile, electrolytes and blood glucose levels of streptozotocin-diabetic rats. J Diabetes 2013; 5:88-94. [PMID: 23374501 DOI: 10.1111/1753-0407.12001] [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] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 07/07/2012] [Accepted: 08/06/2012] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Levcromakalim is a vasorelaxant used in the management of hypertension in diabetes mellitus. Thus, the effects of levcromakalim were investigated in streptozotocin (STZ)-diabetic rats. METHODS Diabetes was induced in Wistar albino rats with a single injection of STZ (60 mg/kg, i.p.) following chronic (4 weeks) treatment with levcromakalim (75 μg/kg per day). Rats were then divided into the following groups (n = 5 in each group): (i) a normal saline (2 mL/kg)-treated group; (ii) a 5 mg/kg glibenclamide-treated group; (iii) 350 mg/kg metformin-treated group; and (iv) 5, 10, 20 and 40 IU/kg insulin-treated groups. Rats were transferred to metabolic cages and the lipid profile, plasma and urine electrolytes and blood glucose levels were determined 24 h after drug administration. RESULTS Levcromakalim treatment significantly reduced total cholesterol, low-density lipoprotein (LDL), and triglyceride levels in diabetic rats (all P < 0.05 compared with untreated diabetic rats). In addition, levcromakalim reduced plasma sodium, bicarbonate, and chloride levels, but increased urinary bicarbonate and chloride levels, in diabetic rats (all P < 0.05 compared with untreated diabetic rats). Levcromakalim significantly inhibited the effects of glibenclamide, metformin, and low-dose (20 IU/kg) insulin treatment in diabetic rats (all P < 0.05). Only 40 IU/kg insulin produced significant reductions in hyperglycemia in levcromakalim-treated diabetic rats. CONCLUSION Levcromakalim induced resistance to glibenclamide, metformin, and low-dose insulin treatment in diabetic rats, leading to persistent hyperglycemia. However, reductions in LDL, total cholesterol and triglyceride levels following chronic levcromokalim treatment may decrease the risk of cardiovascular disease in diabetic rats.
Collapse
Affiliation(s)
- Omonkhelin J Owolabi
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, University of Benin, Benin, Nigeria.
| | | |
Collapse
|
27
|
Cui JH, Gao L, Zhang DX, Xiao ZH, Yang HJ, Li B, Ma GQ, Wang H. [Effect of iptkalim on myocardial enzymes and free radicals metabolism with hypoxic pulmonary hypertension]. Zhongguo Ying Yong Sheng Li Xue Za Zhi 2012; 28:385-388. [PMID: 23252284] [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 explore the effects of iptkalim on myocardial enzymes and free radicals metabolism with hypoxic pulmonary hypertension (HPH), in order to provide evidence for the mechanism of iptkalim on clinical treat. METHODS 110 young men stayed at high altitude above 5 000 m were divided into iptkalim group (n = 74) and placebo group (n = 36), aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyltransferase (gamma-GT), creatine kinase (CK), lactate dehydrogenase (LDH), superoxide dismutase (SOD), malonaldehyde (MDA), nitric oxide(NO) and nitric oxide synthase(NOS) were detected before and after took medicines for 6 mouths. RESULTS After took medication for 6 mouths, ALT, AST, gamma-GT, CK and LDH were reduced, SOD, NO, and NOS were increased, MDA were reduced, there were very significant difference (P < 0.05). CONCLUSION Oxygen free radicals have taken part in the process of HPH, iptkalim have the effect of anti-peroxidation of lipid and protect myocardial cells stress injured by hypoxia which related with mitochondrial membrane and cell membrane's K(ATP) channel activation.
Collapse
Affiliation(s)
- Jian-Hua Cui
- The 18th Hospital of PLA, Xinjiang Yecheng 844900, China
| | | | | | | | | | | | | | | |
Collapse
|
28
|
Ichinomiya T, Cho S, Higashijima U, Matsumoto S, Maekawa T, Sumikawa K. High-dose fasudil preserves postconditioning against myocardial infarction under hyperglycemia in rats: role of mitochondrial KATP channels. Cardiovasc Diabetol 2012; 11:28. [PMID: 22436066 PMCID: PMC3350454 DOI: 10.1186/1475-2840-11-28] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2012] [Accepted: 03/22/2012] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND The current study was carried out to determine whether fasudil hydrochloride (fasudil), a Rho-kinase inhibitor, has myocardial postconditioning (PostC) activity under hyperglycemia as well as normoglycemia, and if so, whether the effects could be mediated by mitochondrial ATP-sensitive potassium (m-KATP) channels. METHODS Male Sprague-Dawley rats were anesthetized with sodium pentobarbital. After opening the chest, all rats underwent 30-min coronary artery occlusion followed by 2-h reperfusion. The rats received low-dose (0.15 mg/kg) or high-dose (0.5 mg/kg) fasudil or diazoxide, an m-KATP channel opener, at 10 mg/kg, just before reperfusion under normoglycemic or hyperglycemic conditions. In another group, rats received 5-hydroxydecanoic acid (5HD), an m-KATP channel blocker, at 10 mg/kg, before high-dose fasudil. Myocardial infarct size was expressed as a percentage of area at risk (AAR). RESULTS Under normoglycemia, low-dose and high-dose fasudil and diazoxide reduced myocardial infarct size (23 ± 8%, 21 ± 9% and 21 ± 10% of AAR, respectively) compared with that in the control (42 ± 7%). Under hyperglycemia, low-dose fasudil (40 ± 11%) and diazoxide (44 ± 14%) could not exert this beneficial effect, but high-dose fasudil reduced myocardial infarct size in the same manner as under normoglycemia (21 ± 13%). 5HD prevented fasudil-induced reduction of myocardial infarct size (42 ± 13%). CONCLUSION Fasudil induces PostC against myocardial infarction via activation of m-KATP channels in the rat. Although hyperglycemia attenuates the PostC, high-dose fasudil can restore cardioprotection.
Collapse
Affiliation(s)
- Taiga Ichinomiya
- Department of Anesthesiology, Nagasaki University School of Medicine, Nagasaki, Japan
| | - Sungsam Cho
- Department of Anesthesiology, Nagasaki University School of Medicine, Nagasaki, Japan
- Department of Anesthesiology, Nagasaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki 852-8501, Japan
| | - Ushio Higashijima
- Department of Anesthesiology, Nagasaki University School of Medicine, Nagasaki, Japan
| | - Shuhei Matsumoto
- Department of Anesthesiology, Nagasaki University School of Medicine, Nagasaki, Japan
| | - Takuji Maekawa
- Department of Anesthesiology, Nagasaki University School of Medicine, Nagasaki, Japan
| | - Koji Sumikawa
- Department of Anesthesiology, Nagasaki University School of Medicine, Nagasaki, Japan
| |
Collapse
|
29
|
Vadziuk OB. [Effects of diazoxide on the mitochondrial membrane potential and ROS generation in rat uterus cells]. Fiziol Zh (1994) 2012; 58:86-92. [PMID: 22590743] [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: 05/31/2023]
Abstract
In the present study we demonstrate partial depolarization of the mitochondrial inner membrane from the rat uterus cells upon activation of mitochondrial ATP-sensitive K(+)-channel (mitoK(ATP)) with diazoxide. The estimated affinity constant of diazoxide to mitoK(ATP) from rat uterus cells is (5.01 +/- 1.47) 10(-6) M. We also observed an enhanced generation of reactive oxygen species after addition of diazoxide. Both effects were effectively eliminated by glybenclamide, blocker of the ATP-sensitive K+ channel. Our results indicate that activation of mitoK(ATP) in rat uterus cells leads to a partial depolarization of mitochondrial membrane and an increase in ROS concentration.
Collapse
|
30
|
Calloe K, Nof E, Jespersen T, Di Diego JM, Chlus N, Olesen SP, Antzelevitch C, Cordeiro JM. Comparison of the effects of a transient outward potassium channel activator on currents recorded from atrial and ventricular cardiomyocytes. J Cardiovasc Electrophysiol 2011; 22:1057-66. [PMID: 21457383 PMCID: PMC3136585 DOI: 10.1111/j.1540-8167.2011.02053.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
INTRODUCTION NS5806 activates the transient outward potassium current (I(to) ) in canine ventricular cells. We compared the effects of NS5806 on canine atrial versus ventricular tissues and myocytes. METHODS AND RESULTS NS5806 (10 μM) was evaluated in arterially perfused canine right atrial and right ventricular wedge preparations. In ventricular wedges NS5806 (10 μM) accentuated phase 1 in epicardium (Epi), with little effect in endocardium (Endo), resulting in augmented J-waves on the ECG. In contrast, application of NS5806 (10 μM) to atrial preparations had no effect on phase 1 repolarization but significantly decreased upstroke velocity (dV/dt) and depressed excitability, consistent with sodium channel block. Current and voltage-clamp recordings were made in the absence and presence of NS5806 in (10 μM) enzymatically dissociated atrial and ventricular myocytes. In ventricular myocytes, NS5806 increased I(to) magnitude by 80% and 16% in Epi and Endo, respectively (at +40 mV). In atrial myocytes, NS5806 increased peak I(to) by 25% and had no effect on the sustained current, I(Kur) . Under control conditions, I(Na) density in atrial myocytes was nearly double that in ventricular myocytes. NS5806 caused a shift in steady-state mid-inactivation (V(1/2)) from -73.9 ± 0.27 to -77.3 ± 0.21 mV in ventricular and from -82.6 ± 0.12 to -85.1 ± 0.11 mV in atrial cells, resulting in reduction of I(Na) in both cell types. Expression of mRNA encoding putative I(Na) and I(to) channel subunits was evaluated by qPCR. CONCLUSION NS5806 produces a prominent augmentation of I(to) with little effect on I(Na) in the ventricles, but a potent inhibition of I(Na) with little augmentation of I(to) in atria.
Collapse
Affiliation(s)
- Kirstine Calloe
- Danish National Research Foundation Center for Cardiac Arrhythmias, University of Copenhagen, Copenhagen, Denmark
| | - Eyal Nof
- Leviev Heart Center, Sheba Medical Center, Tel Hashomer, Ramat Gan, Israel
| | - Thomas Jespersen
- Danish National Research Foundation Center for Cardiac Arrhythmias, University of Copenhagen, Copenhagen, Denmark
| | - José M Di Diego
- Department of Experimental Cardiology, Masonic Medical Research Laboratory Utica, New York, USA
| | - Natalie Chlus
- Department of Experimental Cardiology, Masonic Medical Research Laboratory Utica, New York, USA
| | - Søren-Peter Olesen
- Danish National Research Foundation Center for Cardiac Arrhythmias, University of Copenhagen, Copenhagen, Denmark
| | - Charles Antzelevitch
- Department of Experimental Cardiology, Masonic Medical Research Laboratory Utica, New York, USA
| | - Jonathan M Cordeiro
- Department of Experimental Cardiology, Masonic Medical Research Laboratory Utica, New York, USA
| |
Collapse
|
31
|
Badziuk OB, Mazur II, Kosterin SO. [Regulation of the mitochondrial ATP-sensitive potassium channel in rat uterus cells by ROS]. Ukr Biokhim Zh (1999) 2011; 83:48-57. [PMID: 21888054] [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: 05/31/2023]
Abstract
In previous study we demonstrated the presence of ATP-sensitive potassium current in the inner mitochondrial membrane, which was sensitive to diazoxide and glybenclamide, in mitochondria isolated from the rat uterus. This current was supposed to be operated by mitochondrial ATP-sensitive potassium channel (mitoK(ATP)). Regulation of the mitoK(ATP) in uterus cells is not studied well enough yet. It is well known that the reactive oxygen species (ROS) can play a dual role. They can damage cells in high concentrations, but they can also act as messengers in cellular signaling, mediating survival of cells under stress conditions. ROS are known to activate mitoK(ATP) during the oxidative stress in the brain and heart, conferring the protection of cells. The present study examined whether ROS mediate the mitoK(ATP) activation in myometrium cells. Oxidative stress was induced by rotenone. ROS generation was measured by 2',7'-dichlorofluorescin diacetate. The massive induction of ROS production was demonstrated in the presence of rotenone. Hyperpolarization of the mitochondrial membrane was also detected with the use of the potential-sensitive dye DiOC6 (3,3'-dihexyloxacarbocyanine iodide). Diazoxide, a selective activator of mitoK(ATP), depolarized mitochondrial membrane either under oxidative stress or under normal conditions, while mitoK(ATP) blocker glybenclamide effectively restored mitochondrial potential in rat myocytes. Estimated <K1/2> value for diazoxide to mitoK(ATP) under normoxia was four times higher than under oxidative stress conditions: 5.01 +/- 1.47-10(-6) M and 1.24 +/- 0.21 x 10(-6) M respectively. The ROS scavenger N-acetylcysteine (NAC) successfully eliminates depolarization of mitochondrial membrane by diazoxide under oxidative stress. These results suggest that elimination of ROS by NAC prevents the activation of mitoK(ATP) under oxidative stress. Taking into account the higher affinity of diazoxide to mitoK(ATP) under stress conditions than under normoxia, we conclude that the oxidative stress conditions are more favourable than normoxia for the activation of mitoK(ATP). Thus we hypothesize that the ROS regulate the activity of the mitoK(ATP) in myocytes.
Collapse
|
32
|
Zhang S, Liang R, Zhou F, Huang X, Ding JH, Hu G. Reversal of rotenone-induced dysfunction of astrocytic connexin43 by opening mitochondrial ATP-sensitive potassium channels. Cell Mol Neurobiol 2010; 31:111-7. [PMID: 20824494 DOI: 10.1007/s10571-010-9560-6] [Citation(s) in RCA: 18] [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] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Accepted: 08/25/2010] [Indexed: 12/21/2022]
Abstract
Growing evidence suggests that the astrocytic gap junctions (GJs), mainly formed by connexin 43 (Cx43), play an important role in physiological maintenance and various central nervous system (CNS) pathological conditions. However, little is known about the role of Cx43 in Parkinson's disease (PD). In this article, we report that rotenone, a classic neurotoxin for PD, could inhibit expression of astrocytic Cx43 and gap junction permeability. ATP-sensitive potassium (K(ATP)) channel openers, iptakalim (IPT) and diazoxide (DZ), exerted protective effect on rotenone-induced dysfunction of Cx43 and astrocyte apoptosis, which was reversed by selective mitochondrial K(ATP) (mitoK(ATP)) channel blocker 5-hydroxydecanoate (5-HD). Taken together, our findings reveal that rotenone-induced dysfunction of astrocytic Cx43 may be involved in the pathology of PD. Moreover, opening mitoK(ATP) channels in astrocytes can reverse rotenone-induced dysfunction of astrocytic Cx43 and therefore protect against toxicity of rotenone on astrocytes.
Collapse
Affiliation(s)
- Shu Zhang
- Department of Pharmacology, Nanjing Medical University, Jiangsu, People's Republic of China
| | | | | | | | | | | |
Collapse
|
33
|
Abstract
A major aspect of stimulation of β-cell function by glucose is the induction of electrical activity. The ionic events that underlie β-cell electrical activity are understood in some detail. At sub-stimulatory glucose concentrations, the β-cell is electrically 'silent'. Increasing the glucose concentration to stimulatory levels results in a gradual depolarisation of the membrane potential to a threshold potential where 'spikes' or action potentials are generated. These action potentials represent the gating of voltage-sensitive Ca²(+) channels, leading to Ca²(+) entry into the cell, thus triggering the release of insulin. The stimulatory actions of glucose on the β-cell depend on the metabolism of the hexose. A major question concerns the molecular mechanism(s) whereby β-cell plasma membrane potential is regulated by changes in glucose metabolism in the cell. This article provides a brief summary of the evidence suggesting that, in addition to metabolically-regulated K(ATP) channels, β-cells are equipped with a volume-regulated anion channel that is activated by glucose concentrations within the range effective in modulating electrical activity and insulin release.
Collapse
|
34
|
Lee CH, Choi KY, Kim YJ, Kim WG. Neuroprotective Effect of KR-31378, a Novel Potassium Channel Activator, on Spinal Cord Ischemic Injury in Rabbits. J INVEST SURG 2009; 18:297-304. [PMID: 16319050 DOI: 10.1080/08941930500328219] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Neurologic deficits after the surgical repair of thoracic and thoracoabdominal aortic disease are devastating complications. Recently, pharmacologic preconditioning with potassium channel openers was reported to protect the spinal cord against neurologic injury in a model of spinal cord ischemia. A novel benzopyran derivative with an N-cyanoguanidine group, KR-31378, has been synthesized as a new therapeutic agent against ischemic injury. In the present study, we evaluated the protective effects of KR-31378 on spinal cord ischemic injury and compared its neuroprotective activities and hemodynamic stabilities with those of diazoxide. Thirty-four New Zealand white rabbits were randomly divided into four groups: ischemia group (n = 10, 25 min of aortic cross-clamping without any intervention), diazoxide group (n = 8, diazoxide [5 mg/kg] intravenously 15 min before the 25-min cross-clamping), KR20 group (n = 8, KR-31378 [20 mg/kg] intravenously 30 min before the 25-min cross-clamping), and the KR50 group (n = 8, KR-31378 [50 mg/kg] intravenously 30 min before the 25-min cross-clamping). Neurologic functions were evaluated for 72 h postoperatively using modified Tarlov's scores. All rabbits were sacrificed for histopathologic observations after finally scoring neurologic function. All rabbits but three survived. The rest were completely evaluated 72 h postoperatively. Unlike diazoxide-treated rabbits, KR-31378-treated rabbits showed relatively stable hemodynamics. Tarlov's score outcomes showed a marked improvement in the diazoxide group, in the KR20 group, and in the KR50 group compared to the ischemia group (p = .005, .002, and .001, respectively). However, Tarlov's scores in the KR50 group were not significantly different from those of the diazoxide group. Histopathologic data were not significantly different between the groups, but the degree of degenerative change in motor neurons showed a significant correlation with Tarlov's scores 3 days postoperatively (gamma = -.378, p = .036). Thus, the administration of KR-31378 before the aortic cross-clamping resulted in a significant improvement in neurologic outcome with stable hemodynamics in this rabbit model.
Collapse
Affiliation(s)
- Chang-Ha Lee
- Department of Cardiac Surgery, Sejong General Hospital, Bucheon, Korea
| | | | | | | |
Collapse
|
35
|
Ehrlich JR. Arrhythmogenic Brugada syndrome substrate: a proof of principle. Cardiovasc Res 2009; 81:635-6. [PMID: 19136529 DOI: 10.1093/cvr/cvp008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
36
|
Sandhiya S, Dkhar SA. Potassium channels in health, disease & development of channel modulators. Indian J Med Res 2009; 129:223-232. [PMID: 19491413] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023] Open
Abstract
Ion channels present in the plasma membrane and intracellular organelles of all cells, play an important role in maintaining cellular integrity, smooth muscle contraction, secretion of hormones and neurotransmitters. Among the ion channels, potassium channels (K(+)) are the most abundant having important role in cardiac repolarization, smooth muscle relaxation and insulin release. These are also involved in the regulation of physiological functions like gastrointestinal peristalsis. These channels are the most diverse of all ion channels and are coded by at least 75 genes. Moreover, these have different subunits which co-assemble to form diverse functional channels. Abnormalities in K(+) channels are associated with diseases like long QT syndrome, Anderson Tawil syndrome, epilepsy, type 2 diabetes mellitus, etc. A number of naturally occurring as well as synthetic compounds have been identified that modulate the opening and closure of K(ATP) Channels. Some of the currently available K(+) channel modulators like sulphonylureas, minoxidil, amiodarone, etc. lack tissue selectivity and have adverse effects. Hence, the success of K(ATP) channel modulators depend on their tissue selectivity. Molecular level studies are needed to understand the type of K(+) channels as this can lead to the development of newer drugs with tissue selectivity for various diseases.
Collapse
Affiliation(s)
- Selvarajan Sandhiya
- Department of Pharmacology, Jawaharlal Institute of Postgraduate Medical Education & Research Puducherry, India.
| | | |
Collapse
|
37
|
Hernández-Pacheco A, Araiza-Saldaña CI, Granados-Soto V, Mixcoatl-Zecuatl T. Possible participation of the nitric oxide-cyclic GMP-protein kinase G-K+ channels pathway in the peripheral antinociception of melatonin. Eur J Pharmacol 2008; 596:70-6. [PMID: 18755181 DOI: 10.1016/j.ejphar.2008.07.068] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Revised: 07/02/2008] [Accepted: 07/31/2008] [Indexed: 11/19/2022]
Abstract
The possible participation of the nitric oxide (NO)-cyclic GMP-protein kinase G (PKG)-K(+) channel pathway on melatonin-induced local antinociception was assessed during the second phase of the formalin test. The local peripheral ipsilateral, but not contralateral, administration of melatonin (150-600 microg/paw) produced a dose-related antinociception during both phases of the formalin test in rats. Moreover, local pretreatment with N(G)-L-nitro-arginine methyl ester (L-NAME, NO synthesis inhibitor, 10-100 microg/paw), 1H-(1,2,4)-oxadiazolo(4,2-a)quinoxalin-1-one (ODQ, guanylyl cyclase inhibitor, 5-50 microg/paw), (9S, 10R, 12R)-2,3,9,10,11,12-hexahydro-10-methoxy-2,9-dimethyl-1-oxo-9,12-epoxy-1H-diindolo [1,2,3-fg:3',2',1'-kl]pyrrolo [3,4-i][1,6] benzodiazocine-10-carboxylic acid methyl ester (KT-5823, specific PKG inhibitor, 50-500 ng/paw), glibenclamide (ATP-sensitive K(+) channel blocker, 5-50 microg/paw), apamin (small-conductance Ca(2+)-activated K(+) channel blocker, 0.1-1 microg/paw) or charybdotoxin (large- and intermediate-conductance Ca(2+)-activated K(+) channel blocker, 0.03-0.3 microg/paw), but not N(G)-D-nitro-arginine methyl ester (D-NAME, inactive isomer of L-NAME, 100 microg/paw) or vehicle, significantly prevented melatonin (300 microg/paw)-induced antinociception. Data suggest that melatonin-induced local peripheral antinociception during the second phase of the test could be due to activation of the NO-cyclic GMP-PKG-ATP-sensitive and Ca(2+)-activated K(+) channels pathway.
Collapse
|
38
|
Oztürk GS, Vural M, Gündüz MG, Simşek R, Sarioğlu Y, Safak C. Synthesis of 2-methyl-4-aryl-4,6,7,8-tetrahydro-5(1H)-quinolone derivatives and their effects on potassium channels. Arzneimittelforschung 2008; 58:659-665. [PMID: 19202738 DOI: 10.1055/s-0031-1296568] [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] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In this study, twelve compounds having 2-methyl-4-aryl-4,6,7,8-tetrahydro-5(1H)-quinolone structure have been synthesized by the reaction of 4-aryl-3-butene-2-on derivatives with 1,3-cyclohexanedione analogs in the presence of ammonium acetate in methanol. The structures of the compounds have been elucidated by IR, 1H-NMR, 13C-NMR, mass spectroscopy and elementel analysis. Their potassium channel opener activities have been investigated on isolated rabbit bladder smooth muscle using pinacidil (CAS 85371-64-8) as standard. The test compounds and pinacidil caused concentration-dependent relaxation responses in bladder smooth muscle strips precontracted with 80 mmol/L KCl with the efficacy order: pinacidil > or = 3g > or = 3j > or = 3a > or = 3l = 3i > or = 3c = 3b > or = 3d > or = 3h > or = 3k. In bladder smooth muscle strips precontracted with 15 mmol/L KCl, the efficacy order was: pinacidil > 3h > or = 3c > or = 3j > or = 3g > or = 3l > or = 3i = 3b > or = 3k > or = 3f > or = 3a. The test compounds and pinacidil caused concentration-dependent inhibition of electrical field stimulation-evoked contractile responses in the bladder smooth muscle strips with the efficacy order: 3j > or = 3l pinacidil > or = 3k > or = 3h > or = 3a > or = 3g > or = 3c > or = 3i > or = 3b > or = 3f.
Collapse
Affiliation(s)
- Gökçe Sevim Oztürk
- Department of Pharmacology, Faculty of Medicine, Gazi University, Ankara, Turkey
| | | | | | | | | | | |
Collapse
|
39
|
Zdravkovic M, Kruse M, Rost KL, Møss J, Kecskes A. The effects of NN414, a SUR1/Kir6.2 selective potassium channel opener in subjects with type 2 diabetes. Exp Clin Endocrinol Diabetes 2007; 115:405-6. [PMID: 17701889 DOI: 10.1055/s-2007-973062] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [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: 10/23/2022]
Abstract
Reducing the workload of the beta cell by inhibiting insulin secretion may provide beneficial effects for patients with type 2 diabetes. The aim of this study was to investigate the effect of NN414, a beta cell selective potassium channel opener in patients with type 2 diabetes. 24 patients were treated for seven days (placebo, 1.5, 4.5, and 10 mg/kg). In accordance with the pharmacological profile a significant and selective inhibition of insulin secretion was observed (1 h post dose). There were no statistically significant effects on overall glycaemic control. Based on OGTT derived parameters a borderline significant improvement in beta-cell function (1st and 2nd phase insulin secretion) was observed from Day 1 to Day 7.
Collapse
|
40
|
Wu SN, Lin MW, Wang YJ. Stimulatory actions of di-8-butyl-amino-naphthyl-ethylene-pyridinium-propyl-sulfonate (di-8-ANEPPS), voltage-sensitive dye, on the BKCa channel in pituitary tumor (GH3) cells. Pflugers Arch 2007; 455:687-99. [PMID: 17701422 DOI: 10.1007/s00424-007-0329-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Revised: 07/16/2007] [Accepted: 07/24/2007] [Indexed: 11/29/2022]
Abstract
Di-8-ANEPPS (4-{2-[6-(dibutylamino)-2-naphthalenyl]-ethenyl}-1-(3-sulfopropyl)pyridinium inner salt) has been used as a fast-response voltage-sensitive styrylpyridinium probe. However, little is known regarding the mechanism of di-8-ANEPPS actions on ion currents. In this study, the effects of this dye on ion currents were investigated in pituitary GH(3) cells. In whole-cell configuration, di-8-ANEPPS (10 microM) reversibly increased the amplitude of Ca(2+)-activated K(+) current. In inside-out configuration, di-8-ANEPPS (10 microM) applied to the intracellular surface of the membrane caused no change in single-channel conductance; however, it did enhance the activity of large-conductance Ca(2+)-activated K(+) (BK(Ca)) channels with an EC(50) value of 7.5 microM. This compound caused a left shift in the activation curve of BK(Ca) channels with no change in the gating charge of these channels. A decrease in mean closed time of the channels was seen in the presence of this dye. In the cell-attached mode, di-8-ANEPPS applied on the extracellular side of the membrane also activated BK(Ca) channels. However, neither voltage-gated K(+) nor ether-à-go-go-related gene (erg)-mediated K(+) currents in GH(3) cells were affected by di-8-APPNES. Under current-clamp configuration, di-8-ANEPPS (10 microM) decreased the firing of action potentials in GH(3) cells. In pancreatic betaTC-6 cells, di-8-APPNES (10 microM) also increased BK(Ca)-channel activity. Taken together, this study suggests that during the exposure to di-8-ANEPPS, the stimulatory effects on BK(Ca) channels could be one of potential mechanisms through which it may affect cell excitability.
Collapse
Affiliation(s)
- Sheng-Nan Wu
- Department of Physiology, National Cheng Kung University Medical College, No. 1, University Road, Tainan 70101 Taiwan, Republic of China.
| | | | | |
Collapse
|
41
|
Flynn GE, Black KD, Islas LD, Sankaran B, Zagotta WN. Structure and rearrangements in the carboxy-terminal region of SpIH channels. Structure 2007; 15:671-82. [PMID: 17562314 PMCID: PMC2219339 DOI: 10.1016/j.str.2007.04.008] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [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: 01/17/2007] [Revised: 04/09/2007] [Accepted: 04/20/2007] [Indexed: 11/20/2022]
Abstract
Hyperpolarization-activated cyclic nucleotide-modulated (HCN) ion channels regulate the spontaneous firing activity and electrical excitability of many cardiac and neuronal cells. The modulation of HCN channel opening by the direct binding of cAMP underlies many physiological processes such as the autonomic regulation of the heart rate. Here we use a combination of X-ray crystallography and electrophysiology to study the allosteric mechanism for cAMP modulation of HCN channels. SpIH is an invertebrate HCN channel that is activated fully by cAMP, but only partially by cGMP. We exploited the partial agonist action of cGMP on SpIH to reveal the molecular mechanism for cGMP specificity of many cyclic nucleotide-regulated enzymes. Our results also elaborate a mechanism for the allosteric conformational change in the cyclic nucleotide-binding domain and a mechanism for partial agonist action. These mechanisms will likely extend to other cyclic nucleotide-regulated channels and enzymes as well.
Collapse
Affiliation(s)
- Galen E Flynn
- Department of Physiology and Biophysics, Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA
| | | | | | | | | |
Collapse
|
42
|
Mokhort NA, Samarskaia IV, Iagupol'skaia LM. [Comparative study of the effects of new fluorine-containing pinacidyl analogs on bladder contractile function and vessel tone]. Eksp Klin Farmakol 2007; 70:32-34. [PMID: 18078040] [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: 05/25/2023]
Abstract
The effects of four new fluorine-containing pinacidyl analogs (FPs) on the bladder contractile function in vitro and in vivo, and on the vessel tone in vitro were examined. All the four drugs produced a concentration-dependent relaxation of isolated rat detrusor strips and isolated aorta rings. The contractility inhibition effect of compound FP-5 was decreased by preliminary glibenclamide perfusion. This compound also effectively inhibited bladder contractility function in vivo.
Collapse
|
43
|
Meotti FC, Fachinetto R, Maffi LC, Missau FC, Pizzolatti MG, Rocha JBT, Santos ARS. Antinociceptive action of myricitrin: Involvement of the K+ and Ca2+ channels. Eur J Pharmacol 2007; 567:198-205. [PMID: 17467689 DOI: 10.1016/j.ejphar.2007.03.039] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2006] [Revised: 03/15/2007] [Accepted: 03/19/2007] [Indexed: 01/23/2023]
Abstract
The present study was designed to investigate the mechanisms involved in the antinociception afforded by myricitrin in chemical models of nociception in mice. Myricitrin given by intrathecal (i.t.) or intracerebroventricular (i.c.v.) route produced dose-related antinociception when evaluated against acetic acid-induced visceral pain in mice. In addition, the intraperitoneal administration of myricitrin caused significant inhibition of biting behaviour induced by i.t. injection of glutamate, substance P, capsaicin, interleukin 1 beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha). The antinociception caused by myricitrin in the acetic acid test was fully prevented by i.t. pre-treatment with pertussis toxin, a Gi/o protein inactivator, and by i.c.v. injection of calcium chloride (CaCl(2)). In addition, the i.t. pre-treatment of mice with apamin, a blocker of small (or low)-conductance calcium-gated K(+) channels and tetraethylammonium, a blocker of voltage-gated K(+) channels significantly reversed the antinociception induced by myricitrin. The charybdotoxin, a blocker of large (or fast)-conductance calcium-gated K(+) channels and glibenclamide, a blocker of the ATP-gated K(+) channels had no effect on myricitrin-induced antinociception. Calcium uptake analysis revealed that myricitrin inhibited (45)Ca(2+) influx under a K(+)-induced depolarization condition. However, calcium movement was modified in a non-depolarizing condition only when the highest concentration of myricitrin was used. In summary, our findings indicate that myricitrin produces consistent antinociception in chemical models of nociception in mice. These results clearly demonstrate an involvement of the Gi/o protein dependent mechanism on antinociception caused by myricitrin. The opening of voltage- and small-conductance calcium-gated K(+) channels and the reduction of calcium influx led to the antinociceptive of myricitrin.
Collapse
Affiliation(s)
- Flavia Carla Meotti
- Departamento de Química, Universidade Federal de Santa Maria, 97110-000, Santa Maria, RS, Brazil
| | | | | | | | | | | | | |
Collapse
|
44
|
Abstract
BACKGROUND AND PURPOSE The aim of this study was to investigate the role of different K(+) channel populations and the inhibitory effect of various exogenously applied K(+) channel openers in the regulation of slow wave activity in the guinea-pig prostate. EXPERIMENTAL APPROACH Recordings of membrane potential were made using intracellular microelectrodes. KEY RESULTS Tetraethylammonium (TEA 300 micro M and 1 mM), iberiotoxin (150 nM) and 4-aminopyridine (4-AP 1 mM) increased the frequency of slow wave discharge. Apamin (1-200 nM) and glibenclamide (1 micro M) had no effect on slow wave activity. Lemakalim (1 micro M) and PCO-400 (1 micro M) abolished the slow waves, as did sodium nitroprusside (SNP 10 micro M) and calcitonin gene-related peptide (CGRP 100 nM). The inhibitory effect of these agents was independent of a significant change in membrane potential. In the presence of 4-AP (1 mM), TEA (1 mM) or glibenclamide (1 micro M) the inhibitory actions of SNP (10 micro M) were attenuated. The inhibitory actions of CGRP (100 nM) were also reversed by glibenclamide (1 micro M). In contrast, isoprenaline (1 micro M) did not alter the frequency of slow wave discharge. CONCLUSIONS AND IMPLICATIONS These results demonstrate that BK(Ca) and 4-AP-sensitive K(+) channels regulate the frequency of prostatic slow wave discharge. SNP and CGRP abolish slow waves in a hyperpolarisation-independent manner, partially via opening of K(ATP) channels. BK(Ca) and 4-AP-sensitive K(+) channels also play an important role in the SNP-induced inhibition of slow wave activity. The lack of membrane hyperpolarisation associated with the SNP- and CGRP-induced inhibition implies that the channels involved in this action are not predominantly located on the smooth muscle cells.
Collapse
Affiliation(s)
- D-T T Nguyen
- Department of Pharmaceutical Biology and Pharmacology, Prostate Research Co-operative, Victorian College of Pharmacy, Monash University Parkville Victoria, Australia
| | - R J Lang
- Department of Physiology, Monash University Clayton Victoria, Australia
| | - B Exintaris
- Department of Pharmaceutical Biology and Pharmacology, Prostate Research Co-operative, Victorian College of Pharmacy, Monash University Parkville Victoria, Australia
- Author for correspondence:
| |
Collapse
|
45
|
Shafaroodi H, Asadi S, Sadeghipour H, Ghasemi M, Ebrahimi F, Tavakoli S, Hajrasouliha AR, Dehpour AR. Role of ATP-sensitive potassium channels in the biphasic effects of morphine on pentylenetetrazole-induced seizure threshold in mice. Epilepsy Res 2007; 75:63-9. [PMID: 17517498 DOI: 10.1016/j.eplepsyres.2007.04.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2006] [Revised: 04/13/2007] [Accepted: 04/16/2007] [Indexed: 01/31/2023]
Abstract
Although several studies have indicated that the opioid receptor agonist morphine exerts biphasic effects on clonic seizure threshold, as yet little is known of the underlying mechanisms in this effect. In the present study, using the specific ATP-sensitive K(+) (K(ATP)) channel blocker glibenclamide and the specific K(ATP) channel opener cromakalim, the possible involvement of K(ATP) channels in the effects of morphine on pentylenetetrazole (PTZ)-induced seizure threshold in mice was investigated. Acute administration of lower doses of morphine (1, 3 and 7.5 mg/kg, i.p.) increased and higher doses of morphine (30 and 60 mg/kg, i.p.) decreased the PTZ-induced seizure threshold. Glibenclamide (2.5-5 mg/kg) increased the PTZ-induced seizure threshold. Non-effective dose of cromakalim (0.1 microg/kg) inhibited anticonvulsant effect of glibenclamide (5 mg/kg). Acute administration of non-effective dose of glibenclamide (1 mg/kg) interestingly inhibited both anticonvulsant and pro-convulsant effects of morphine and this effect was significantly reversed by cromakalim (0.1 microg/kg). These results support the involvement of K(ATP) channels in the modulation of seizure threshold by morphine.
Collapse
Affiliation(s)
- Hamed Shafaroodi
- Department of Pharmacology, Tehran Medical Unit, Islamic Azad University, Tehran, Iran
| | | | | | | | | | | | | | | |
Collapse
|
46
|
Yeung SYM, Pucovský V, Moffatt JD, Saldanha L, Schwake M, Ohya S, Greenwood IA. Molecular expression and pharmacological identification of a role for K(v)7 channels in murine vascular reactivity. Br J Pharmacol 2007; 151:758-70. [PMID: 17519950 PMCID: PMC2014117 DOI: 10.1038/sj.bjp.0707284] [Citation(s) in RCA: 150] [Impact Index Per Article: 8.8] [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] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND AND PURPOSE This study represents a novel characterisation of KCNQ-encoded potassium channels in the vasculature using a variety of pharmacological and molecular tools to determine their role in contractility. EXPERIMENTAL APPROACH Reverse transcriptase polymerase chain reaction (RT-PCR) experiments were undertaken on RNA isolated from mouse aorta, carotid artery, femoral artery and mesenteric artery using primers specific for all known KCNQ genes. RNA isolated from mouse heart and brain were used as positive controls. Pharmacological experiments were undertaken on segments from the same blood vessels to determine channel functionality. Immunocytochemical experiments were performed on isolated myocytes from thoracic aorta. KEY RESULTS All blood vessels expressed KCNQ1, 4 and 5 with hitherto 'neuronal' KCNQ4 being, surprisingly, the most abundant. The correlated proteins K(v)7.1, K(v)7.4 and K(v)7.5 were identified in the cell membranes of aortic myocytes by immunocytochemistry. Application of three compounds known to activate K(v)7 channels, retigabine (2 -20 microM), flupirtine (20 microM) and meclofenamic acid (20 microM), relaxed vessels precontracted by phenylephrine or 1 mM 4-aminopyridine but had no effect on contractions produced by 60 mM KCl or the K(v)7 channel blocker XE991 (10 microM). All vessels tested contracted upon application of the K(v)7 channel blockers XE991 and linopirdine (0.1-10 microM). CONCLUSIONS AND IMPLICATIONS Murine blood vessels exhibit a distinctive KCNQ expression profile with 'neuronal' KCNQ4 dominating. The ion channels encoded by KCNQ genes have a crucial role in defining vascular reactivity as K(v)7 channel blockers produced marked contractions whereas K(v)7 channel activators were effective vasorelaxants.
Collapse
Affiliation(s)
- S Y M Yeung
- Division of Basic Medical Sciences, Ion Channels and Cell Signalling Research Centre, St George's, University of London London, UK
| | - V Pucovský
- Cell and Metabolic Signalling Research Group, School of Medicine and Dentistry, Queen's University BelfastUK
| | - J D Moffatt
- Department of Veterinary Basic Sciences, The Royal Veterinary College London, UK
| | - L Saldanha
- Division of Basic Medical Sciences, Ion Channels and Cell Signalling Research Centre, St George's, University of London London, UK
| | - M Schwake
- Institute of Biochemistry, Christian-Albrechts University Kiel, Germany
| | - S Ohya
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City UniversityJapan
| | - I A Greenwood
- Division of Basic Medical Sciences, Ion Channels and Cell Signalling Research Centre, St George's, University of London London, UK
- Author for correspondence:
| |
Collapse
|
47
|
Gu R, Wang J, Zhang Y, Li W, Xu Y, Shan H, Wang WH, Yang B. Adenosine stimulates the basolateral 50 pS K channels in the thick ascending limb of the rat kidney. Am J Physiol Renal Physiol 2007; 293:F299-305. [PMID: 17475899 DOI: 10.1152/ajprenal.00008.2007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [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] [Indexed: 11/22/2022] Open
Abstract
We used the patch-clamp technique to examine the effect of adenosine on the basolateral K channels in the thick ascending limb (TAL) of the rat kidney. A 50-pS inwardly rectifying K channel was detected in the basolateral membrane, and the channel activity was decreased by hyperpolarization. Application of adenosine (10 microM) increased the activity of basolateral 50 pS K channels, defined by NP(o), from 0.21 to 0.41. The effect of adenosine on the 50 pS K channels was mimicked by cyclohexyladenosine (CHA), which increased channel activity by a dose-dependent manner. However, inhibition of the A1 adenosine receptor with 8-cyclopentyl-1, 3-dipropylxanthine (DPCPX) failed to block the effect of CHA. In contrast, application of 8-(3-chlorostyryl) caffeine (CSC), an A2 adenosine antagonist, abolished the stimulatory effect of CHA. The possibility that the effect of adenosine and adenosine analog on the basolateral 50 pS K channel was the result of activation of the A2 adenosine receptor was also suggested by the observation that application of CGS-21680, a selected A(2A) adenosine receptor agonist, increased the channel activity. Also, inhibition of PKA with N-[2-(methylamino)ethyl]-5-isoquinoline sulfonamide-2HC1 abolished the stimulatory effect of CHA on the basolateral 50 pS K channel. Moreover, addition of the membrane-permeable cAMP analog increases the activity of 50 pS K channels. We conclude that adenosine activates the 50 pS K channel in the basolateral membrane of the TAL and the stimulatory effect is mainly mediated by a PKA-dependent pathway via the A2 adenosine receptor in the TAL.
Collapse
Affiliation(s)
- Ruimin Gu
- Dept. of Pharmacology, Harbin Medical University, Harbin 150086, China
| | | | | | | | | | | | | | | |
Collapse
|
48
|
Conde CMS, Cyrino FZGA, Bottino DA, Gardette J, Bouskela E. Longchain n-3 polyunsaturated fatty acids and microvascular reactivity: Observation in the hamster cheek pouch. Microvasc Res 2007; 73:237-47. [PMID: 17196224 DOI: 10.1016/j.mvr.2006.11.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2006] [Revised: 11/10/2006] [Accepted: 11/14/2006] [Indexed: 10/01/2022]
Abstract
Previous experiments in our laboratory, using the hamster cheek pouch microcirculation, have shown that precapillary vessels exhibit spontaneous rhythmic luminal variations, termed vasomotion, a myogenic activity sustained by a balance between membrane currents among which polarizing K(+) currents play an important role. In these microvessels, endothelium-derived relaxing factors (EDRFs) seem to regulate arteriolar diameter [via nitric oxide (NO) and cyclic GMP] and vasomotion [probably via endothelium-derived hyperpolarizing factor (EDHF)]. Fish or fish oil diet can decrease the risk of cardiovascular diseases, probably by modifying the conductance of selective ion channels, such as K(+) and/or Ca(++), and/or increasing the production of vasodilators, such as NO. To investigate its effect on microvascular reactivity, using the same preparation and an intravital microscope coupled to a closed circuit TV system, male hamsters were treated for 14 days, twice a day, with 0.4 mL/100 g body weight with fish or olive oil. An attempt was also undertaken to record in arterioles, in vivo, the membrane potential of smooth muscle cells during their vasomotor activity combining conventional microelectrode and intravital microscopy techniques. The effects of topical application of two vasodilators, acetylcholine [endothelium-dependent one, NO release and membrane hyperpolarization via Ca(++)-activated K(+) channels (K(Ca))] and sodium nitroprusside (endothelium-independent, NO donor and no change on membrane potential) and two vasoconstrictors which elicited membrane depolarization via Ca(++) channels, phenylephrine (alpha(1)-adrenergic receptor agonist) and serotonin (5-hydroxi-tryptamine) on mean internal diameter of arterioles and venules, arteriolar blood flows, spontaneous arteriolar vasomotion frequency and amplitude and functional capillary density (FCD, number of capillaries with flowing red blood cells per unit area of tissue) were determined. Anesthesia was induced by sodium pentobarbital (i.p.) and maintained with alpha-chloralose through the femoral vein. In the presence of vasomotion, the membrane potentials are slowly oscillating by about 20 mV around values of approximately -50 mV in perfect synchrony with vasomotor movements and depolarizing phases coincide with vasoconstrictions while polarizing ones with vasodilatations. Comparing all parameters, in control conditions, only the spontaneous vasomotion frequency was significantly higher (2.37 times higher) on the group treated with fish oil and persisted as such throughout all experiments. With topical application of the drugs mentioned above, the group treated with fish oil showed, for each drug concentration, a balance towards vasodilatation with consequent increase on arteriolar blood flow and on FCD, compared with the olive oil treated one. No significant changes on mean arterial pressure, spontaneous arteriolar vasomotion amplitude or venular diameter could be detected in the two groups. Our results support the concept that, in the hamster cheek pouch microcirculation, fish oil supplementation activates K(+) channels which act as the EDHF and might also increase the production of vasodilators, probably NO.
Collapse
Affiliation(s)
- Cristiane M S Conde
- Laboratório de Pesquisas em Microcirculação, Pavilhão Reitor Haroldo Lisboa da Cunha, térreo, Universidade do Estado do Rio de Janeiro, Rua São Francisco Xavier, 524, 20550-013 Rio de Janeiro RJ, Brazil
| | | | | | | | | |
Collapse
|
49
|
Carreira R, Monteiro P, Gonçalves LM, Providência LA. Nicorandil preserves the function of the mitochondrial phosphorylative and oxidative system in an animal model of global ischemia-reperfusion. Rev Port Cardiol 2007; 26:521-8. [PMID: 17691278] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023] Open
Abstract
Ischemia followed by reperfusion (IR) negatively affects mitochondrial function. At the level of the oxidative-phosphorylative system, IR inhibits the respiratory complexes and ATP synthase, and increases the passive leak of protons through the inner mitochondrial membrane, uncoupling respiration from phosphorylation, decreasing mitochondrial potential and, consequently, ATP production. Drugs that minimize the mitochondrial damage induced by IR may prove to be clinically effective. In the present work, we analyzed the impact of nicorandil, a mitochondrial ATP-sensitive potassium channel agonist, on mitochondrial dysfunction at the level of the oxidative-phosphorylative system of rat hearts subjected to IR. The decrease in the respiratory control ratio (RCR) induced by IR leads to the conclusion that IR has a negative impact on the activity of the mitochondrial respiratory system, uncoupling oxidation from phosphorylation. This effect is reversed by nicorandil, which increases not only RCR, but also the ADP/O ratio. Regarding respiratory rate, state 3 rate was approximately the same for all the experimental groups, while state 4 rate was lower for the group where IR was induced in the presence of nicorandil. This result is in accordance with the data obtained for the RCR and ADP/O. State 4 rate is most affected by uncoupling, given that it is controlled by proton leak. Mitochondria subjected to IR in the presence of nicorandil have a lower state 4 rate, i.e. they are less uncoupled. From these results we conclude that nicorandil preserves the function of mitochondria subjected to IR in terms of both respiration and phosphorylative capacity.
Collapse
Affiliation(s)
- Raquel Carreira
- Serviço de Cardiologia, Hospitais da Universidade de Coimbra, Coimbra, Portugal
| | | | | | | |
Collapse
|
50
|
Zhang H, Liu YY, Ma Y, Lu YL. [Protective effect of ATP sensitive potassium channel opener on cerebral ischemia/reperfusion injury and its signal transduction mechanism]. Zhongguo Wei Zhong Bing Ji Jiu Yi Xue 2007; 19:221-4. [PMID: 17448277] [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: 05/15/2023]
Abstract
OBJECTIVE To study the protective effect of ATP sensitive potassium channel(K( ATP))opener against neuronal apoptosis following focal cerebral ischemia/reperfusion (I/R) and its signal transduction mechanism. METHODS Two hundred male Wistar rats were randomly divided into four groups: sham operation group (A group), I/R group (B group), K( ATP) opener treatment group (C group) and K( ATP) opener and blocker treatment group (D group). The middle cerebral artery occlusion (MCAO) by intraluminal suture method was used to reproduce cerebral ischemia, and perfusion was restored 2 hours after MCAO. Five rats in each group were used. Brain sections were made 6, 12, 24, 48 and 72 hours after I/R injury, and neuronal apoptosis was detected by terminal deoxynucleotidyl transferase-mediated deoxyuridine 5 triphosphate nick end labeling (TUNEL). The expressions of caspase-3 and caspase-9 proteins were detected by immunohistochemical method. Another five rats in each group were used for assessing the expressions of caspase-3 mRNA and caspase-9 mRNA by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS The number of apoptotic neurons, the expression of caspase-3 and caspase-9 mRNA and protein in B, C and D groups were significantly higher than A group at all time points (P<0.05 or P<0.01). The number of apoptotic neurons, the expressions of caspase-3 and caspase-9 mRNA and protein in C group were significantly lower than B and D groups at all time points (P<0.05 or P<0.01). There were no differences between B and D groups at all time points (all P>0.05). CONCLUSION K( ATP) opener can significantly mitigate neuronal apoptosis and inhibit the expressions of caspase-3 and caspase-9 mRNA and protein after cerebral I/R injury. This result indicates that K( ATP) opener can decrease neuronal apoptosis by inhibiting mitochondria signaling pathway.
Collapse
Affiliation(s)
- Hong Zhang
- Department of Neurology, The Second Affiliated Hospital of China Medical University, Shenyang, Liaoning, China
| | | | | | | |
Collapse
|