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Sharma A, Rahman G, Gorelik J, Bhargava A. Voltage-Gated T-Type Calcium Channel Modulation by Kinases and Phosphatases: The Old Ones, the New Ones, and the Missing Ones. Cells 2023; 12:461. [PMID: 36766802 PMCID: PMC9913649 DOI: 10.3390/cells12030461] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/14/2023] [Accepted: 01/29/2023] [Indexed: 02/04/2023] Open
Abstract
Calcium (Ca2+) can regulate a wide variety of cellular fates, such as proliferation, apoptosis, and autophagy. More importantly, changes in the intracellular Ca2+ level can modulate signaling pathways that control a broad range of physiological as well as pathological cellular events, including those important to cellular excitability, cell cycle, gene-transcription, contraction, cancer progression, etc. Not only intracellular Ca2+ level but the distribution of Ca2+ in the intracellular compartments is also a highly regulated process. For this Ca2+ homeostasis, numerous Ca2+ chelating, storage, and transport mechanisms are required. There are also specialized proteins that are responsible for buffering and transport of Ca2+. T-type Ca2+ channels (TTCCs) are one of those specialized proteins which play a key role in the signal transduction of many excitable and non-excitable cell types. TTCCs are low-voltage activated channels that belong to the family of voltage-gated Ca2+ channels. Over decades, multiple kinases and phosphatases have been shown to modulate the activity of TTCCs, thus playing an indirect role in maintaining cellular physiology. In this review, we provide information on the kinase and phosphatase modulation of TTCC isoforms Cav3.1, Cav3.2, and Cav3.3, which are mostly described for roles unrelated to cellular excitability. We also describe possible potential modulations that are yet to be explored. For example, both mitogen-activated protein kinase and citron kinase show affinity for different TTCC isoforms; however, the effect of such interaction on TTCC current/kinetics has not been studied yet.
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Affiliation(s)
- Ankush Sharma
- Department of Biotechnology, Indian Institute of Technology Hyderabad (IITH), Kandi 502284, Telangana, India
| | - Ghazala Rahman
- Department of Biotechnology, Indian Institute of Technology Hyderabad (IITH), Kandi 502284, Telangana, India
| | - Julia Gorelik
- National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London W12 0NN, UK
| | - Anamika Bhargava
- Department of Biotechnology, Indian Institute of Technology Hyderabad (IITH), Kandi 502284, Telangana, India
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2
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Li Q, Zhu H, Fan M, Sun J, Reinach PS, Wang Y, Qu J, Zhou X, Zhao F. Form-deprivation myopia downregulates calcium levels in retinal horizontal cells in mice. Exp Eye Res 2022; 218:109018. [PMID: 35240197 DOI: 10.1016/j.exer.2022.109018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 02/14/2022] [Accepted: 02/25/2022] [Indexed: 11/25/2022]
Abstract
The process of eye axis lengthening in myopic eyes is regulated by multiple mechanisms in the retina, and horizontal cells (HCs) are an essential interneuron in the visual regulatory system. Wherein intracellular Ca2+ plays an important role in the events involved in the regulatory role of HCs in the retinal neural network. It is unknown if intracellular Ca2+ regulation in HCs mediates changes in the retinal neural network during myopia progression. We describe here a novel calcium fluorescence indicator system that monitors HCs' intracellular Ca2+ levels during form-deprivation myopia (FDM) in mice. AAV injection of GCaMP6s, as a protein calcium sensor, into a Gja10-Cre mouse monitored the changes in Ca2+signaling in HC that accompany FDM progression in mice. An alternative Gja10-Cre/Ai96-GCaMP6s mouse model was created by cross mating Gja10-Cre with Ai96 mice. Immunofluorescence imaging and live imaging of the retinal cells verified the identity of these animal models. Changes in retinal horizontal cellular Ca2+ levels were resolved during FDM development. The numbers of GCaMP6s and the proportion of HCs were tracked based on profiling changes in GCaMP6s+calbindin+/calbindin+ coimmunostaining patterns. They significantly decreased more after either two days (P < 0.01) or two weeks (P < 0.001) in form deprived eyes than in the untreated fellow eyes. These decreases in their proportion reached significance only in the retinal central region rather than also in the retinal periphery. A novel approach employing a GCaMP6s mouse model was developed that may ultimately clarify if HCs mediate Ca2+ signals that contribute to controlling FDM progression in mice. The results indicate so far that FDM progression is associated with declines in HC Ca2+ signaling activity.
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Affiliation(s)
- Qihang Li
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China; State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China
| | - He Zhu
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China; State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China
| | - Miaomiao Fan
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China; State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China
| | - Jing Sun
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China; State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China
| | - Peter S Reinach
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China; State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China
| | - Yuhan Wang
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China; State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China
| | - Jia Qu
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China; State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China; Research Unit of Myopia Basic Research and Clinical Prevention and Control, Chinese Academy of Medical Sciences (2019RU025), Wenzhou, Zhejiang, China; Oujiang Laboratory, Zhejiang Lab for Regenerative Medicine, Vision and Brain Health, Wenzhou, Zhejiang, China
| | - Xiangtian Zhou
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China; State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China; Research Unit of Myopia Basic Research and Clinical Prevention and Control, Chinese Academy of Medical Sciences (2019RU025), Wenzhou, Zhejiang, China; Oujiang Laboratory, Zhejiang Lab for Regenerative Medicine, Vision and Brain Health, Wenzhou, Zhejiang, China.
| | - Fuxin Zhao
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China; State Key Laboratory of Optometry, Ophthalmology and Vision Science, Wenzhou, Zhejiang, China.
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3
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Country MW, Jonz MG. Mitochondrial KATP channels stabilize intracellular Ca2+ during hypoxia in retinal horizontal cells of goldfish (Carassius auratus). J Exp Biol 2021; 224:271844. [PMID: 34402511 DOI: 10.1242/jeb.242634] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 08/11/2021] [Indexed: 01/20/2023]
Abstract
Neurons of the retina require oxygen to survive. In hypoxia, neuronal ATP production is impaired, ATP-dependent ion pumping is reduced, transmembrane ion gradients are dysregulated, and intracellular Ca2+ concentration ([Ca2+]i) increases enough to trigger excitotoxic cell death. Central neurons of the common goldfish (Carassius auratus) are hypoxia tolerant, but little is known about how goldfish retinas withstand hypoxia. To study the cellular mechanisms of hypoxia tolerance, we isolated retinal interneurons (horizontal cells; HCs), and measured [Ca2+]i with Fura-2. Goldfish HCs maintained [Ca2+]i throughout 1 h of hypoxia, whereas [Ca2+]i increased irreversibly in HCs of the hypoxia-sensitive rainbow trout (Oncorhynchus mykiss) with just 20 min of hypoxia. Our results suggest mitochondrial ATP-dependent K+ channels (mKATP) are necessary to stabilize [Ca2+]i throughout hypoxia. In goldfish HCs, [Ca2+]i increased when mKATP channels were blocked with glibenclamide or 5-hydroxydecanoic acid, whereas the mKATP channel agonist diazoxide prevented [Ca2+]i from increasing in hypoxia in trout HCs. We found that hypoxia protects against increases in [Ca2+]i in goldfish HCs via mKATP channels. Glycolytic inhibition with 2-deoxyglucose increased [Ca2+]i, which was rescued by hypoxia in a mKATP channel-dependent manner. We found no evidence of plasmalemmal KATP channels in patch-clamp experiments. Instead, we confirmed the involvement of KATP in mitochondria with TMRE imaging, as hypoxia rapidly (<5 min) depolarized mitochondria in a mKATP channel-sensitive manner. We conclude that mKATP channels initiate a neuroprotective pathway in goldfish HCs to maintain [Ca2+]i and avoid excitotoxicity in hypoxia. This model provides novel insight into the cellular mechanisms of hypoxia tolerance in the retina.
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Affiliation(s)
- Michael W Country
- Department of Biology, University of Ottawa, Ottawa, ON, CanadaK1N 6N5
| | - Michael G Jonz
- Department of Biology, University of Ottawa, Ottawa, ON, CanadaK1N 6N5.,Brain and Mind Research Institute, University of Ottawa, Ottawa, ON, CanadaK1H 8M5
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4
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Van Hook MJ, Nawy S, Thoreson WB. Voltage- and calcium-gated ion channels of neurons in the vertebrate retina. Prog Retin Eye Res 2019; 72:100760. [PMID: 31078724 PMCID: PMC6739185 DOI: 10.1016/j.preteyeres.2019.05.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 04/25/2019] [Accepted: 05/01/2019] [Indexed: 02/06/2023]
Abstract
In this review, we summarize studies investigating the types and distribution of voltage- and calcium-gated ion channels in the different classes of retinal neurons: rods, cones, horizontal cells, bipolar cells, amacrine cells, interplexiform cells, and ganglion cells. We discuss differences among cell subtypes within these major cell classes, as well as differences among species, and consider how different ion channels shape the responses of different neurons. For example, even though second-order bipolar and horizontal cells do not typically generate fast sodium-dependent action potentials, many of these cells nevertheless possess fast sodium currents that can enhance their kinetic response capabilities. Ca2+ channel activity can also shape response kinetics as well as regulating synaptic release. The L-type Ca2+ channel subtype, CaV1.4, expressed in photoreceptor cells exhibits specific properties matching the particular needs of these cells such as limited inactivation which allows sustained channel activity and maintained synaptic release in darkness. The particular properties of K+ and Cl- channels in different retinal neurons shape resting membrane potentials, response kinetics and spiking behavior. A remaining challenge is to characterize the specific distributions of ion channels in the more than 100 individual cell types that have been identified in the retina and to describe how these particular ion channels sculpt neuronal responses to assist in the processing of visual information by the retina.
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Affiliation(s)
- Matthew J Van Hook
- Truhlsen Eye Institute, Department of Ophthalmology & Visual Sciences, University of Nebraska Medical Center, Omaha, NE, USA
| | - Scott Nawy
- Truhlsen Eye Institute, Department of Ophthalmology & Visual Sciences, University of Nebraska Medical Center, Omaha, NE, USA; Department Pharmacology & Experimental Neuroscience(2), University of Nebraska Medical Center, Omaha, NE, USA
| | - Wallace B Thoreson
- Truhlsen Eye Institute, Department of Ophthalmology & Visual Sciences, University of Nebraska Medical Center, Omaha, NE, USA; Department Pharmacology & Experimental Neuroscience(2), University of Nebraska Medical Center, Omaha, NE, USA.
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5
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Si W, Zhang Y, Chen K, Hu D, Qian Z, Gong S, Li H, Hao Y, Tao J. Fibroblast growth factor type 1 receptor stimulation of T-type Ca2+ channels in sensory neurons requires the phosphatidylinositol 3-kinase and protein kinase A pathways, independently of Akt. Cell Signal 2018; 45:93-101. [DOI: 10.1016/j.cellsig.2018.01.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 01/25/2018] [Accepted: 01/25/2018] [Indexed: 02/08/2023]
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6
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Nadim F, Bucher D. Neuromodulation of neurons and synapses. Curr Opin Neurobiol 2014; 29:48-56. [PMID: 24907657 DOI: 10.1016/j.conb.2014.05.003] [Citation(s) in RCA: 194] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 05/09/2014] [Accepted: 05/09/2014] [Indexed: 12/15/2022]
Abstract
Neuromodulation underlies the flexibility of neural circuit operation and behavior. Individual neuromodulators can have divergent actions in a neuron by targeting multiple physiological mechanisms. Conversely, multiple neuromodulators may have convergent actions through overlapping targets. The divergent and convergent neuromodulator actions can be unambiguously synergistic or antagonistic, but neuromodulation often entails balanced adjustment of nonlinear membrane and synaptic properties by targeting ion channel and synaptic dynamics rather than just excitability or synaptic strength. In addition, neuromodulators can exert effects at multiple timescales, from short-term adjustments of neuron and synapse function to persistent long-term regulation. This short review summarizes some highlights of the diverse actions of neuromodulators on ion channel and synaptic properties.
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Affiliation(s)
- Farzan Nadim
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University, 323 Martin Luther King Blvd, Newark, NJ 07102, United States.
| | - Dirk Bucher
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University, 323 Martin Luther King Blvd, Newark, NJ 07102, United States
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7
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Chen W, Ke JB, Wu HJ, Miao Y, Li F, Yang XL, Wang Z. Somatostatin receptor-mediated suppression of gabaergic synaptic transmission in cultured rat retinal amacrine cells. Neuroscience 2014; 273:118-27. [PMID: 24846611 DOI: 10.1016/j.neuroscience.2014.05.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 05/05/2014] [Accepted: 05/06/2014] [Indexed: 01/03/2023]
Abstract
Somatostatin (SRIF) modulates neurotransmitter release by activating the specific receptors (sst1-sst5). Our previous study showed that sst5 receptors are expressed in rat retinal GABAergic amacrine cells. Here, we investigated modulation of GABA release by SRIF in cultured amacrine cells, using patch-clamp techniques. The frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) in the amacrine cells was significantly reduced by SRIF, which was partially reversed by BIM 23056, an sst5 receptor antagonist, and was further rescued by addition of CYN-154806, an sst2 receptor antagonist. Both nimodipine, an L-type Ca2+ channel blocker, and ω-conotoxin GVIA, an N-type Ca2+ channel blocker, suppressed the sIPSC frequency, and in the presence of nimodipine and ω-conotoxin GVIA, SRIF failed to further suppress the sIPSC frequency. Extracellular application of forskolin, an activator of adenylate cyclase, increased the sIPSC frequency, while the membrane permeable protein kinase A (PKA) inhibitor Rp-cAMP reduced it, and in the presence of Rp-cAMP, SRIF did not change sIPSCs. However, SRIF persisted to suppress the sIPSCs in the presence of KT5823, a protein kinase G (PKG) inhibitor. Moreover, pre-incubation with Bis IV, a protein kinase C (PKC) inhibitor, or pre-application of xestospongin C, an inositol 1,4,5-trisphosphate receptor (IP3R) inhibitor, SRIF still suppressed the sIPSC frequency. All these results suggest that SRIF suppresses GABA release from the amacrine cells by inhibiting presynaptic Ca2+ channels, in part through activating sst5/sst2 receptors, a process that is mediated by the intracellular cAMP-PKA signaling pathway.
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Affiliation(s)
- W Chen
- Institutes of Brain Science, Institute of Neurobiology and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China
| | - J B Ke
- Institutes of Brain Science, Institute of Neurobiology and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China
| | - H J Wu
- Institutes of Brain Science, Institute of Neurobiology and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China
| | - Y Miao
- Institutes of Brain Science, Institute of Neurobiology and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China
| | - F Li
- Institutes of Brain Science, Institute of Neurobiology and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China
| | - X L Yang
- Institutes of Brain Science, Institute of Neurobiology and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China
| | - Z Wang
- Institutes of Brain Science, Institute of Neurobiology and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China.
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8
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Ul-Hussain M, Dermietzel R, Zoidl G. Connexins and Cap-independent translation: role of internal ribosome entry sites. Brain Res 2012; 1487:99-106. [PMID: 22771397 DOI: 10.1016/j.brainres.2012.05.065] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 05/18/2012] [Indexed: 02/05/2023]
Abstract
Cap-independent translation using an internal ribosome entry site instead of the 5'-Cap structure has been discovered in positive-sense RNA viruses and eukaryotic genomes including a subset of gap junction forming connexins genes. With a growing number of mutations found in human connexin genes and studies on genetically modified mouse models mechanisms highlighting the important role of gap junctional communication in multicellular organism it is obvious that mechanism need to be in place to preserve this critical property even under conditions when Cap-mediated translation is scrutinized. To ensure sustained gap junctional communication, rapid initiation of translation of preexisting connexin mRNAs is one possibility, and the presence of internal ribosome entry sites in gap junction genes comply with such a requirement. In this review, we will summarize past and recent findings to build a case for IRES mediated translation as an alternative regulatory pathway facilitating gap junctional communication. This article is part of a Special Issue entitled Electrical Synapses.
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Affiliation(s)
- Mahboob Ul-Hussain
- Biotechnology, University of Kashmir, India; Neuroanatomy, Ruhr-University, Bochum, Germany
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9
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Modulation of low-voltage-activated T-type Ca²⁺ channels. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1828:1550-9. [PMID: 22975282 DOI: 10.1016/j.bbamem.2012.08.032] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 08/29/2012] [Accepted: 08/30/2012] [Indexed: 12/16/2022]
Abstract
Low-voltage-activated T-type Ca²⁺ channels contribute to a wide variety of physiological functions, most predominantly in the nervous, cardiovascular and endocrine systems. Studies have documented the roles of T-type channels in sleep, neuropathic pain, absence epilepsy, cell proliferation and cardiovascular function. Importantly, novel aspects of the modulation of T-type channels have been identified over the last few years, providing new insights into their physiological and pathophysiological roles. Although there is substantial literature regarding modulation of native T-type channels, the underlying molecular mechanisms have only recently begun to be addressed. This review focuses on recent evidence that the Ca(v)3 subunits of T-type channels, Ca(v)3.1, Ca(v)3.2 and Ca(v)3.3, are differentially modulated by a multitude of endogenous ligands including anandamide, monocyte chemoattractant protein-1, endostatin, and redox and oxidizing agents. The review also provides an overview of recent knowledge gained concerning downstream pathways involving G-protein-coupled receptors. This article is part of a Special Issue entitled: Calcium channels.
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Activation of M3 muscarinic receptors inhibits T-type Ca(2+) channel currents via pertussis toxin-sensitive novel protein kinase C pathway in small dorsal root ganglion neurons. Cell Signal 2011; 23:1057-67. [PMID: 21329754 DOI: 10.1016/j.cellsig.2011.02.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 01/28/2011] [Accepted: 02/07/2011] [Indexed: 11/23/2022]
Abstract
Cobrotoxin (CbT), a short-chain postsynaptic α-neurotoxin, has been reported to play a role in analgesia. However, to date, the detailed mechanisms still remain unknown. In the present study, we identify a novel functional role of CbT in modulating T-type Ca(2+) channel currents (T-currents) in small dorsal root ganglia (DRG) neurons as well as pain behaviors in mice. We found that CbT inhibited T-currents in a dose-dependent manner. CbT at 1μM reversibly inhibited T-currents by ~26.3%. This inhibitory effect was abolished by the non-selective muscarinic acetylcholine receptor (mAChR) antagonist atropine, or the selective M3 mAChR antagonist 4-DAMP, while naloxone, an opioid receptor antagonist had no effect. Intracellular infusion of GDP-β-S or pretreatment of the cells with pertussis toxin (PTX) completely blocked the inhibitory effects of CbT. Using depolarizing prepulse, we found the absence of direct binding between G-protein βγ subunits and T-type Ca(2+) channels in CbT-induced T-current inhibition. CbT responses were abolished by the phospholipase C inhibitor U73122 (but not the inactive analog U73343). The classical and novel protein kinase C (nPKC) antagonist chelerythrine chlorid or GF109203X abolished CbT responses, whereas the classical PKC antagonist Ro31-8820 or inhibition of PKA elicited no such effects. Intrathecal administration of CbT (5μg/kg) produced antinociceptive effects in mechanical, thermal, and inflammatory pain models. Moreover, CbT-induced antinociception could be abrogated by 4-DAMP. Taken together, these results suggest that CbT acting through M3 mAChR inhibits T-currents via a PTX-sensitive nPKC pathway in small DRG neurons, which could contribute to its analgesic effects in mice.
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Liu K, Jiang D, Zhang T, Tao J, Shen L, Sun X. Activation of Growth Hormone Secretagogue Type 1a Receptor Inhibits T-type Ca 2+ Channel Currents through Pertussis Toxin-sensitive Novel Protein Kinase C Pathway in Mouse Spermatogenic Cells. Cell Physiol Biochem 2011; 27:613-24. [DOI: 10.1159/000329983] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/05/2011] [Indexed: 11/19/2022] Open
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Antidepressant-like effects of echo-planar magnetic resonance imaging in mice determined using the forced swimming test. Brain Res 2008; 1236:194-9. [PMID: 18755160 DOI: 10.1016/j.brainres.2008.08.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2007] [Revised: 08/06/2008] [Accepted: 08/08/2008] [Indexed: 02/06/2023]
Abstract
Echo-planar magnetic resonance imaging (EP-MRI), which is novel variant of MRI, is thought to have antidepressant properties in humans and animal models. Using the forced swimming test (FST), we investigated which monoaminergic system in mice is affected by EP-MRI. The short- and long-term effects of EP-MRI on immobility time in the FST and motor activity within a locomotor activity cage were examined. Two groups of mice underwent 20 min of EP-MRI in an MR scanner (Siemens, 1.5 T Symphony) either 23.5 or 1 h before the start of the second session of the FST. In both groups, the immobility duration in the FST was reduced, similar to effective antidepressant drug treatments. Climbing behavior in the 1-h group and swimming behavior in the 23.5-h group increased significantly, similar to that seen after the administration of desipramine (a noradrenaline reuptake inhibitor) and sertraline (a selective serotonin reuptake inhibitor), respectively. The findings support the hypothesis that EP-MRI has an antidepressant-like effect. We suggest that the antidepressant-like effect begins in the early period with noradrenaline systems and is maintained in the late period with serotonin systems.
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13
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Vigh J, Lasater EM. L-type calcium channels mediate transmitter release in isolated,
wide-field retinal amacrine cells. Vis Neurosci 2004; 21:129-34. [PMID: 15259564 DOI: 10.1017/s095252380404204x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Transmitter release in neurons is triggered by intracellular
Ca2+ increase via the opening of voltage-gated
Ca2+ channels. Here we investigated the voltage-gated
Ca2+ channels in wide-field amacrine cells (WFACs) isolated
from the white-bass retina that are functionally coupled to transmitter
release. We monitored transmitter release through the measurement of
the membrane capacitance (Cm). We found
that 500-ms long depolarizations of WFACs from −70 mV to 0 mV
elicited about a 6% transient increase in the
Cm or membrane surface area. This
Cm jump could be eliminated either by
intracellular perfusion with 10 mM BAPTA or by extracellular
application of 4 mM cobalt. WFACs possess N-type and L-type
voltage-gated Ca2+ channels. Depolarization-evoked
Cm increases were unaffected by the
specific N-type channel blocker ω-conotoxin GVIA, but they were
markedly reduced by the L-type blocker diltiazem, suggesting a role for
the L-type channel in synaptic transmission. Further supporting this
notion, in WFACs the synaptic protein syntaxin always colocalized with
the pore-forming subunit of the retinal specific L-type channels
(CaV1.4 or α1F), but never with that of the N-type
channels (CaV2.2 or α1B).
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Affiliation(s)
- Jozsef Vigh
- Department of Ophthalmology and Visual Sciences, John Moran Eye Center, University of Utah, Health Sciences Center, Salt Lake City 84132, USA
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Vigh J, Solessio E, Morgans CW, Lasater EM. Ionic mechanisms mediating oscillatory membrane potentials in wide-field retinal amacrine cells. J Neurophysiol 2003; 90:431-43. [PMID: 12649310 DOI: 10.1152/jn.00092.2003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Particular types of amacrine cells of the vertebrate retina show oscillatory membrane potentials (OMPs) in response to light stimulation. Historically it has been thought the oscillations arose as a result of circuit properties. In a previous study we found that in some amacrine cells, the ability to oscillate was an intrinsic property of the cell. Here we characterized the ionic mechanisms responsible for the oscillations in wide-field amacrine cells (WFACs) in an effort to better understand the functional properties of the cell. The OMPs were found to be calcium (Ca2+) dependent; blocking voltage-gated Ca2+ channels eliminated the oscillations, whereas elevating extracellular Ca2+ enhanced them. Strong intracellular Ca2+ buffering (10 mM EGTA or bis-(o-aminophenoxy)-N,N,N',N'-tetraacetic acid) eliminated any attenuation in the OMPs as well as a Ca2+-dependent inactivation of the voltage-gated Ca2+ channels. Pharmacological and immunohistochemical characterization revealed that WFACs express L- and N-type voltage-sensitive Ca2+ channels. Block of the L-type channels eliminated the OMPs, but omega-conotoxin GVIA did not, suggesting a different function for the N-type channels. The L-type channels in WFACs are functionally coupled to a set of calcium-dependent potassium (K(Ca)) channels to mediate OMPs. The initiation of OMPs depended on penitrem-A-sensitive (BK) K(Ca) channels, whereas their duration is under apamin-sensitive (SK) K(Ca) channel control. The Ca2+ current is essential to evoke the OMPs and triggering the K(Ca) currents, which here act as resonant currents, enhances the resonance as an amplifying current, influences the filtering characteristics of the cell membrane, and attenuates the OMPs via CDI of the L-type Ca2+ channel.
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Affiliation(s)
- Jozsef Vigh
- Department of Ophthalmology and Visual Sciences, John Moran Eye Center, University of Utah, Health Sciences Center, Salt Lake City, Utah 84132, USA
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Vigh J, Lasater EM. Intracellular calcium release resulting from mGluR1 receptor activation modulates GABAA currents in wide-field retinal amacrine cells: a study with caffeine. Eur J Neurosci 2003; 17:2237-48. [PMID: 12814357 DOI: 10.1046/j.1460-9568.2003.02652.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The modulatory action of calcium (Ca2+) released from intracellular stores on GABAA receptor-mediated current was investigated in wide-field amacrine cells isolated from the teleost, Morone chrysops, retina. Caffeine, ryanodine or inositol 1,4,5-triphosphate (IP3) markedly inhibited the GABAA current by elevating [Ca2+]i. The inhibition resulted from the activation of a Ca2+--> Ca2+/calmodulin --> calcineurin cascade. Long (>12 s) exposure to glutamate mimicked the caffeine effect, i.e. it inhibited the GABAA current by elevating [Ca2+]i through mGluR1 receptor activation and consequent IP3 generation. This pathway provides a 'timed' disinhibitory mechanism to potentiate excitatory postsynaptic potentials in wide-field amacrine cells. It occurs as a result of the suppression of GABA-mediated conductances as a function of the duration of presynaptic excitatory input activity. This is much like some forms of long-term potentiation in the central nervous system. In a local retinal circuit this will selectively accentuate particular excitatory inputs to the wide-field amacrine cell. Similar to other neural systems, we suggest that activity-dependent postsynaptic disinhibition is an important feature of the signal processing in the inner retina.
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MESH Headings
- Amacrine Cells/drug effects
- Amacrine Cells/physiology
- Animals
- Anticoagulants/pharmacology
- Bicuculline/pharmacology
- Caffeine/pharmacology
- Calcium/metabolism
- Calcium Channels/metabolism
- Carps
- Cells, Cultured
- Central Nervous System Stimulants/pharmacology
- Chelating Agents/pharmacology
- Dose-Response Relationship, Drug
- Drug Interactions
- Egtazic Acid/analogs & derivatives
- Egtazic Acid/pharmacology
- Electric Conductivity
- Enzyme Inhibitors/pharmacology
- Excitatory Amino Acid Agonists/pharmacology
- Extracellular Space/metabolism
- GABA Antagonists/pharmacology
- Glutamic Acid/physiology
- Heparin/pharmacology
- Immunohistochemistry
- Inositol 1,4,5-Trisphosphate/pharmacology
- Inositol 1,4,5-Trisphosphate Receptors
- Kainic Acid/pharmacology
- Membrane Potentials/drug effects
- Methoxyhydroxyphenylglycol/analogs & derivatives
- Methoxyhydroxyphenylglycol/pharmacology
- Organophosphorus Compounds/pharmacology
- Patch-Clamp Techniques/methods
- Receptors, Cytoplasmic and Nuclear/metabolism
- Receptors, GABA-A/physiology
- Receptors, Metabotropic Glutamate/antagonists & inhibitors
- Receptors, Metabotropic Glutamate/metabolism
- Retina/cytology
- Ryanodine/pharmacology
- alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid/pharmacology
- gamma-Aminobutyric Acid/pharmacology
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Affiliation(s)
- Jozsef Vigh
- Dept. of Ophthalmology and Visual Sciences, John Moran Eye Center, University of Utah, Health Sciences Center, Salt Lake City, UT 84132, USA
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16
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Sacca GB, Sáenz DA, Jaliffa CO, Minces L, Keller Sarmiento MI, Rosenstein RE. Photic regulation of heme oxygenase activity in the golden hamster retina: involvement of dopamine. J Neurochem 2003; 85:534-42. [PMID: 12675930 DOI: 10.1046/j.1471-4159.2003.01697.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The photic regulation of heme oxygenase (HO) activity was examined in the golden hamster retina. This enzymatic activity was significantly higher at midday than at midnight. When the hamsters were placed under constant darkness for 48 h and killed at subjective day or at subjective night, the differences in HO activity disappeared. Western blot analysis showed no differences in HO levels among these time points. Dopamine significantly increased this activity in retinas excised at noon or at midnight, with a higher sensitivity at night. The effect of dopamine was reversed by SCH 23390 but not by spiperone and clozapine and it was not reproduced by quinpirole. In vitro, the increase in HO activity found in retinas incubated under light for 1 h was significantly reduced by SCH 23390. Two cAMP analogs increased HO activity and their effect, as well as the effect of dopamine was blocked by H-89, a protein kinase A (PKA) inhibitor. Tin protoporphyrin IX, an HO inhibitor, significantly decreased cGMP accumulation with maximal effects during the day. Low concentrations of bilirubin decreased retinal thiobarbituric acid substances levels (an index of lipid peroxidation) in basal conditions and after exposing retinal cells to H2O2. These results suggest that hamster retinal HO activity is regulated by the photic stimulus, probably through a dopamine/cAMP/PKA dependent pathway.
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Affiliation(s)
- Geraldine B Sacca
- Laboratorio de Neuroquímica Retiniana y Oftalmología Experimental, Departamento de Bioquímica Humana, Facultad de Medicina, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina
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17
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Zhu PJ, Chiappinelli VA. Nicotinic receptors mediate increased GABA release in brain through a tetrodotoxin-insensitive mechanism during prolonged exposure to nicotine. Neuroscience 2003; 115:137-44. [PMID: 12401328 DOI: 10.1016/s0306-4522(02)00371-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The effects of nicotine on the spontaneous release of GABA from nerve terminals in the chick lateral spiriform nucleus were examined using whole cell patch-clamp recording in brain slices. Exposure to 1 microM nicotine produced an early immediate increase in the frequency of spontaneous postsynaptic GABAergic currents. This effect was blocked in the presence of 0.5 microM tetrodotoxin. However, a prolonged application of 0.1-1 microM nicotine (>3 min) caused a tetrodotoxin-insensitive increase in the frequency of spontaneous GABAergic currents. This late tetrodotoxin-insensitive effect was blocked by the nicotinic antagonists dihydro-beta-erythroidine (30 microM) and mecamylamine (10 microM), but not by methyllycaconitine (50-100 nM), indicating that activation of high affinity nicotine receptors was mainly responsible for this effect. This enhancement was inhibited by the high threshold Ca(2+) channel blocker Cd(2+) (100 microM), but not by dantrolene or ryanodine. The tetrodotoxin-insensitive enhancement of the frequency of GABA currents by nicotine was reduced by inhibition of cAMP-dependent protein kinase with HA1004 (30 microM), but not by inhibition of protein kinase C with staurosporine (1 microM), and was facilitated by forskolin (10 microM) or bromo-cAMP (50 microM). The results indicate that nicotine-enhanced GABA release can operate through both tetrodotoxin-sensitive and -insensitive mechanisms in a single brain region and that a second messenger cascade may be involved in the tetrodotoxin-insensitive enhancement by nicotine.
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Affiliation(s)
- P J Zhu
- Department of Pharmacology, The George Washington University Medical Center, Washington, DC 20037, USA.
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18
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Cho YW, Han SH, Min BI, Rhee JS, Akaike N. Antagonizing effect of protein kinase C activation on the mu-opioid agonist-induced inhibition of high voltage-activated calcium current in rat periaqueductal gray neuron. Brain Res 2001; 916:61-9. [PMID: 11597591 DOI: 10.1016/s0006-8993(01)02864-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Opioids have been thought to induce analgesia by activating the descending pain control system, especially at the level of periaqueductal gray, and regulate the neurotransmitter release through the inhibition of calcium channel. In the present study, the modulatory effects of protein kinase C and protein kinase A on the mu-opioid agonist-induced inhibition of the high-voltage activated calcium current were examined in the acutely dissociated rat periaqueductal gray neurons with the nystatin-perforated patch-clamp technique. Among 505 neurons tested, the barium current passing through the high-voltage activated calcium channels of 172 neurons (34%) were inhibited by 32+/-3% with the application of an mu-opioid agonist, [D-Ala(2),N-MePhe(4),Gly(5)-ol]-enkephalin (DAMGO, 1 microM). The barium currents itself and the DAMGO-induced inhibitory effects were not affected by the application of either an adenylate cyclase activator (forskolin, 1 microM) or a protein kinase inhibitor (staurosporin, 10 nM) for 2 min. The DAMGO inhibition was completely and irreversibly antagonized by the application of a protein kinase C activator, phorbol-12-myristate-13-acetate (PMA, 1 microM) for 2 min without any alteration of the barium current itself. However, the antagonizing effect of PMA was completely abolished by the application of 10 nM staurosporin for 2 min. After then, PMA did not show the antagonizing effect any more. Inversely, when staurosporin was applied before PMA, the antagonizing effect of PMA was also not shown. These results demonstrate that the mu-opioid agonist-induced inhibition of the periaqueductal gray neuronal high-voltage activated calcium current can be antagonized by protein kinase C activation. This finding may provide us a significant clue to understand the action mechanism of opioid-induced analgesia in the periaqueductal gray.
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Affiliation(s)
- Y W Cho
- Department of Physiology, College of Medicine, Kyung Hee University, Seoul 130-701, South Korea.
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Abstract
To understand information processing in the retina, it is important to identify and characterize the types of synaptic receptors and intrinsic ion channels in retinal neurons. In order to achieve a high degree of adaptability, retinal synapses have evolved multiple neuromodulatory mechanisms. Light or modulatory agents can alter the efficacies of both electrical and chemical synaptic transmission in the retina. Recent studies indicate that interaction of voltage-gated channels with those activated by neurotransmitters plays a significant role in shaping the light-evoked postsynaptic responses of retinal neurons. The fact that both types of channels are subject to modulation by multiple second messenger-mediated intracellular processes is a clear indicator of the importance of neuromodulation in retinal function. The whole-cell patch clamp technique provides a means to study mechanisms of regulation of ion channels by controlling intracellular as well as the extracellular environment. This review describes the experimental evidence, mostly obtained in our laboratory, which indicates the important role of Ca-dependent neuromodulatory processes in the regulation of signal transmission in the vertical pathway of the amphibian retina.
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Affiliation(s)
- A Akopian
- Department of Ophthalmology, New York University School of Medicine, New York, New York 10016,
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