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McDevitt DS, Wade QW, McKendrick GE, Nelsen J, Starostina M, Tran N, Blendy JA, Graziane NM. The Paraventricular Thalamic Nucleus and Its Projections in Regulating Reward and Context Associations. eNeuro 2024; 11:ENEURO.0524-23.2024. [PMID: 38351131 PMCID: PMC10883411 DOI: 10.1523/eneuro.0524-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 01/23/2024] [Accepted: 01/23/2024] [Indexed: 02/17/2024] Open
Abstract
The paraventricular thalamic nucleus (PVT) is a brain region that mediates aversive and reward-related behaviors as shown in animals exposed to fear conditioning, natural rewards, or drugs of abuse. However, it is unknown whether manipulations of the PVT, in the absence of external factors or stimuli (e.g., fear, natural rewards, or drugs of abuse), are sufficient to drive reward-related behaviors. Additionally, it is unknown whether drugs of abuse administered directly into the PVT are sufficient to drive reward-related behaviors. Here, using behavioral as well as pathway and cell-type specific approaches, we manipulate PVT activity as well as the PVT-to-nucleus accumbens shell (NAcSh) neurocircuit to explore reward phenotypes. First, we show that bath perfusion of morphine (10 µM) caused hyperpolarization of the resting membrane potential, increased rheobase, and decreased intrinsic membrane excitability in PVT neurons that project to the NAcSh. Additionally, we found that direct injections of morphine (50 ng) in the PVT of mice were sufficient to generate conditioned place preference (CPP) for the morphine-paired chamber. Mimicking the inhibitory effect of morphine, we employed a chemogenetic approach to inhibit PVT neurons that projected to the NAcSh and found that pairing the inhibition of these PVT neurons with a specific context evoked the acquisition of CPP. Lastly, using brain slice electrophysiology, we found that bath-perfused morphine (10 µM) significantly reduced PVT excitatory synaptic transmission on both dopamine D1 and D2 receptor-expressing medium spiny neurons in the NAcSh, but that inhibiting PVT afferents in the NAcSh was not sufficient to evoke CPP.
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Affiliation(s)
- Dillon S McDevitt
- Neuroscience Program, Penn State College of Medicine, Hershey, Pennsylvania 17033
| | - Quinn W Wade
- Department of Anesthesiology and Perioperative Medicine, Penn State College of Medicine, Hershey, Pennsylvania 17033
| | - Greer E McKendrick
- Neuroscience Program, Penn State College of Medicine, Hershey, Pennsylvania 17033
| | - Jacob Nelsen
- Doctor of Medicine Program, Penn State College of Medicine, Hershey, Pennsylvania 17033
| | - Mariya Starostina
- Doctor of Medicine Program, Penn State College of Medicine, Hershey, Pennsylvania 17033
| | - Nam Tran
- Doctor of Medicine Program, Penn State College of Medicine, Hershey, Pennsylvania 17033
| | - Julie A Blendy
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Nicholas M Graziane
- Departments of Anesthesiology and Perioperative Medicine and Pharmacology, Penn State College of Medicine, Hershey, Pennsylvania 17033
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2
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Smith PA. Neuropathic pain; what we know and what we should do about it. FRONTIERS IN PAIN RESEARCH 2023; 4:1220034. [PMID: 37810432 PMCID: PMC10559888 DOI: 10.3389/fpain.2023.1220034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 09/05/2023] [Indexed: 10/10/2023] Open
Abstract
Neuropathic pain can result from injury to, or disease of the nervous system. It is notoriously difficult to treat. Peripheral nerve injury promotes Schwann cell activation and invasion of immunocompetent cells into the site of injury, spinal cord and higher sensory structures such as thalamus and cingulate and sensory cortices. Various cytokines, chemokines, growth factors, monoamines and neuropeptides effect two-way signalling between neurons, glia and immune cells. This promotes sustained hyperexcitability and spontaneous activity in primary afferents that is crucial for onset and persistence of pain as well as misprocessing of sensory information in the spinal cord and supraspinal structures. Much of the current understanding of pain aetiology and identification of drug targets derives from studies of the consequences of peripheral nerve injury in rodent models. Although a vast amount of information has been forthcoming, the translation of this information into the clinical arena has been minimal. Few, if any, major therapeutic approaches have appeared since the mid 1990's. This may reflect failure to recognise differences in pain processing in males vs. females, differences in cellular responses to different types of injury and differences in pain processing in humans vs. animals. Basic science and clinical approaches which seek to bridge this knowledge gap include better assessment of pain in animal models, use of pain models which better emulate human disease, and stratification of human pain phenotypes according to quantitative assessment of signs and symptoms of disease. This can lead to more personalized and effective treatments for individual patients. Significance statement: There is an urgent need to find new treatments for neuropathic pain. Although classical animal models have revealed essential features of pain aetiology such as peripheral and central sensitization and some of the molecular and cellular mechanisms involved, they do not adequately model the multiplicity of disease states or injuries that may bring forth neuropathic pain in the clinic. This review seeks to integrate information from the multiplicity of disciplines that seek to understand neuropathic pain; including immunology, cell biology, electrophysiology and biophysics, anatomy, cell biology, neurology, molecular biology, pharmacology and behavioral science. Beyond this, it underlines ongoing refinements in basic science and clinical practice that will engender improved approaches to pain management.
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Affiliation(s)
- Peter A. Smith
- Neuroscience and Mental Health Institute and Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
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3
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Choudhary S, Kaur R, Waziri A, Garg A, Kadian R, Alam MS. N-type calcium channel blockers: a new approach towards the treatment of chronic neuropathic pain. EXPLORATION OF MEDICINE 2023. [DOI: 10.37349/emed.2023.00126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023] Open
Abstract
Neuropathic pain (NP) remains maltreated for a wide number of patients by the currently available treatments and little research has been done in finding new drugs for treating NP. Ziconotide (PrialtTM) had been developed as the new drug, which belongs to the class of ω-conotoxin MVIIA. It inhibits N-type calcium channels. Ziconotide is under the last phase of the clinical trial, a new non-narcotic drug for the management of NP. Synthetically it has shown the similarities with ω-conotoxin MVIIA, a constituent of poison found in fish hunting snails (Conus magus). Ziconotide acts by selectively blocking neural N-type voltage-sensitized Ca2+ channels (NVSCCs). Certain herbal drugs also have been studied but no clinical result is there and the study is only limited to preclinical data. This review emphasizes the N-type calcium channel inhibitors, and their mechanisms for blocking calcium channels with their remedial prospects for treating chronic NP.
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Affiliation(s)
- Shikha Choudhary
- School of Medical and Allied Sciences, K.R. Mangalam University, Gurugram 122103, Haryana, India
| | - Raminderjit Kaur
- School of Medical and Allied Sciences, K.R. Mangalam University, Gurugram 122103, Haryana, India
| | - Aafrin Waziri
- University School of Biotechnology, Guru Gobind Singh Indraprastha University, Delhi, 110078, India
| | - Arun Garg
- Department of Pharmacology, NIMS Institute of Pharmacy, NIMS University, Jaipur 303121, Rajasthan, India
| | - Renu Kadian
- Ram Gopal College of Pharmacy, Gurugram 122506, Haryana, India
| | - Md Sabir Alam
- SGT College of Pharmacy, SGT University, Gurugram 122505, Haryana, India
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4
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Keimasi M, Salehifard K, Keimasi M, Amirsadri M, Esfahani NMJ, Moradmand M, Esmaeili F, Mofid MR. Alleviation of cognitive deficits in a rat model of glutamate-induced excitotoxicity, using an N-type voltage-gated calcium channel ligand, extracted from Agelena labyrinthica crude venom. Front Mol Neurosci 2023; 16:1123343. [PMID: 36873105 PMCID: PMC9981952 DOI: 10.3389/fnmol.2023.1123343] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 02/06/2023] [Indexed: 02/19/2023] Open
Abstract
Excitotoxicity is a common pathological process in Alzheimer's disease (AD) which is caused by the over-activity of N-Methyl-D-Aspartate receptors (NMDARs). The release of neurotransmitters depends on the activity of voltage-gated calcium channels (VGCCs). Hyper-stimulation of NMDARs can enhance the releasement of neurotransmitters through the VGCCs. This malfunction of channels can be blocked by selective and potent N-type VGCCs ligand. Under excitotoxicity condition, glutamate has negative effects on the pyramidal cells of the hippocampus, which ends in synaptic loss and elimination of these cells. These events leads to learning and memory elimination through the hippocampus circuit's dysfunction. A suitable ligand has a high affinity to receptor or channel and is selective for its target. The bioactive small proteins of venom have these characteristics. Therefore, peptides and small proteins of animal venom are precious sources for pharmacological applications. The omega-agatoxin-Aa2a was purified, and identified from Agelena labyrinthica specimens, as an N-type VGCCs ligand for this study. The effect of the omega-agatoxin-Aa2a on the glutamate-induced excitotoxicity in rats was evaluated through behavioral tests including Morris Water Maze, and Passive avoidance. The syntaxin1A (SY1A), synaptotagmin1 (SYT1), and synaptophysin (SYN) genes expression were measured via Real-Time PCR. The local expression of synaptosomal-associated protein, 25 k Da (SNAP-25) was visualized using an immunofluorescence assay for synaptic quantification. Electrophysiological amplitude of field excitatory postsynaptic potentials (fEPSPs) in the input-output and LTP curves of mossy fiber were recorded. The cresyl violet staining of hippocampus sections was performed for the groups. Our results demonstrated that the omega-agatoxin-Aa2a treatment could recover the learning, and memory impairment caused by NMDA-induced excitotoxicity in rat hippocampus.
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Affiliation(s)
- Mohammad Keimasi
- Department of Plant and Animal Biology, Faculty of Biological Sciences and Technology, University of Isfahan, Isfahan, Iran
| | - Kowsar Salehifard
- Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mohammadjavad Keimasi
- Department of Plant and Animal Biology, Faculty of Biological Sciences and Technology, University of Isfahan, Isfahan, Iran
| | - Mohammadreza Amirsadri
- Department of Clinical Pharmacy and Pharmacy Practice, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Noushin Mirshah Jafar Esfahani
- Department of Plant and Animal Biology, Faculty of Biological Sciences and Technology, University of Isfahan, Isfahan, Iran
| | - Majid Moradmand
- Department of Plant and Animal Biology, Faculty of Biological Sciences and Technology, University of Isfahan, Isfahan, Iran
| | - Fariba Esmaeili
- Department of Plant and Animal Biology, Faculty of Biological Sciences and Technology, University of Isfahan, Isfahan, Iran
| | - Mohammad Reza Mofid
- Department of Clinical Biochemistry, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
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Caminski ES, Antunes FTT, Souza IA, Dallegrave E, Zamponi GW. Regulation of N-type calcium channels by nociceptin receptors and its possible role in neurological disorders. Mol Brain 2022; 15:95. [PMID: 36434658 PMCID: PMC9700961 DOI: 10.1186/s13041-022-00982-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 11/15/2022] [Indexed: 11/27/2022] Open
Abstract
Activation of nociceptin opioid peptide receptors (NOP, a.k.a. opioid-like receptor-1, ORL-1) by the ligand nociceptin/orphanin FQ, leads to G protein-dependent regulation of Cav2.2 (N-type) voltage-gated calcium channels (VGCCs). This typically causes a reduction in calcium currents, triggering changes in presynaptic calcium levels and thus neurotransmission. Because of the widespread expression patterns of NOP and VGCCs across multiple brain regions, the dorsal horn of the spinal cord, and the dorsal root ganglia, this results in the alteration of numerous neurophysiological features. Here we review the regulation of N-type calcium channels by the NOP-nociceptin system in the context of neurological conditions such as anxiety, addiction, and pain.
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Affiliation(s)
- Emanuelle Sistherenn Caminski
- grid.412344.40000 0004 0444 6202Graduate Program in Health Sciences, Laboratory of Research in Toxicology (LAPETOX), Federal University of Health Sciences of Porto Alegre, Porto Alegre, RS Brazil
| | - Flavia Tasmin Techera Antunes
- grid.22072.350000 0004 1936 7697Department of Clinical Neurosciences, University of Calgary, Calgary, AB Canada ,grid.22072.350000 0004 1936 7697Hotchkiss Brain Institute, University of Calgary, Calgary, AB Canada
| | - Ivana Assis Souza
- grid.22072.350000 0004 1936 7697Department of Clinical Neurosciences, University of Calgary, Calgary, AB Canada ,grid.22072.350000 0004 1936 7697Hotchkiss Brain Institute, University of Calgary, Calgary, AB Canada
| | - Eliane Dallegrave
- grid.412344.40000 0004 0444 6202Graduate Program in Health Sciences, Laboratory of Research in Toxicology (LAPETOX), Federal University of Health Sciences of Porto Alegre, Porto Alegre, RS Brazil
| | - Gerald W. Zamponi
- grid.22072.350000 0004 1936 7697Department of Clinical Neurosciences, University of Calgary, Calgary, AB Canada ,grid.22072.350000 0004 1936 7697Hotchkiss Brain Institute, University of Calgary, Calgary, AB Canada
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6
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Zhou J, Ma R, Jin Y, Fang J, Du J, Shao X, Liang Y, Fang J. Molecular mechanisms of opioid tolerance: From opioid receptors to inflammatory mediators (Review). Exp Ther Med 2021; 22:1004. [PMID: 34345286 PMCID: PMC8311239 DOI: 10.3892/etm.2021.10437] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 04/19/2021] [Indexed: 12/14/2022] Open
Abstract
Opioids are considered the most effective analgesics for the treatment of both acute and chronic pain. However, prolonged opioid use can induce a certain level of tolerance to its analgesic effects, leading to a reduction in its effectiveness, addiction and abuse. A better understanding of the mechanisms underlying opioid tolerance may provide insights into this phenomenon and aid in the development of novel methods to combat the side effects of opioid tolerance. The present review focused on two major contributors to tolerance, opioid receptors and inflammatory mediators. The molecular mechanisms involved in the desensitization of the opioid receptors were briefly described, including their phosphorylation, internalisation and recycling. Subsequently, the effects of Toll like receptor 4/NOD-like receptor family pyrin domain containing 3-mediated proinflammatory responses in opioid tolerance were discussed, aiming in supporting the identification of novel therapeutic targets.
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Affiliation(s)
- Jie Zhou
- Department of Acupuncture and Moxibustion, The Third Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310005, P.R. China
| | - Ruijie Ma
- Department of Acupuncture and Moxibustion, The Third Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310005, P.R. China
| | - Ying Jin
- Department of Rehabilitation in Traditional Chinese Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310000, P.R. China
| | - Junfan Fang
- The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, P.R. China
| | - Junying Du
- The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, P.R. China
| | - Xiaomei Shao
- The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, P.R. China
| | - Yi Liang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, P.R. China
| | - Jianqiao Fang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Zhejiang Chinese Medical University, Hangzhou, Zhejiang 310053, P.R. China
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7
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Input-output signal processing plasticity of vagal motor neurons in response to cardiac ischemic injury. iScience 2021; 24:102143. [PMID: 33665562 PMCID: PMC7898179 DOI: 10.1016/j.isci.2021.102143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 01/01/2021] [Accepted: 01/29/2021] [Indexed: 11/23/2022] Open
Abstract
Vagal stimulation is emerging as the next frontier in bioelectronic medicine to modulate peripheral organ health and treat disease. The neuronal molecular phenotypes in the dorsal motor nucleus of the vagus (DMV) remain largely unexplored, limiting the potential for harnessing the DMV plasticity for therapeutic interventions. We developed a mesoscale single-cell transcriptomics data from hundreds of DMV neurons under homeostasis and following physiological perturbations. Our results revealed that homeostatic DMV neuronal states can be organized into distinguishable input-output signal processing units. Remote ischemic preconditioning induced a distinctive shift in the neuronal states toward diminishing the role of inhibitory inputs, with concomitant changes in regulatory microRNAs miR-218a and miR-495. Chronic cardiac ischemic injury resulted in a dramatic shift in DMV neuronal states suggestive of enhanced neurosecretory function. We propose a DMV molecular network mechanism that integrates combinatorial neurotransmitter inputs from multiple brain regions and humoral signals to modulate cardiac health.
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8
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Zhou W, Guan Z. Ion Channels in Anesthesia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1349:401-413. [DOI: 10.1007/978-981-16-4254-8_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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9
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Pineyro G, Nagi K. Signaling diversity of mu- and delta- opioid receptor ligands: Re-evaluating the benefits of β-arrestin/G protein signaling bias. Cell Signal 2020; 80:109906. [PMID: 33383156 DOI: 10.1016/j.cellsig.2020.109906] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/24/2020] [Accepted: 12/27/2020] [Indexed: 01/02/2023]
Abstract
Opioid analgesics are elective for treating moderate to severe pain but their use is restricted by severe side effects. Signaling bias has been proposed as a viable means for improving this situation. To exploit this opportunity, continuous efforts are devoted to understand how ligand-specific modulations of receptor functions could mediate the different in vivo effects of opioids. Advances in the field have led to the development of biased agonists based on hypotheses that allocated desired and undesired effects to specific signaling pathways. However, the prevalent hypothesis associating β-arrestin to opioid side effects was recently challenged and multiple of the newly developed biased drugs may not display the superior side effects profile that was sought. Moreover, biased agonism at opioid receptors is now known to be time- and cell-dependent, which adds a new layer of complexity for bias estimation. Here, we first review the signaling mechanisms underlying desired and undesired effects of opioids. We then describe biased agonism at opioid receptors and discuss the different perspectives that support the desired and undesired effects of opioids in view of exploiting biased signaling for therapeutic purposes. Finally, we explore how signaling kinetics and cellular background can influence the magnitude and directionality of bias at those receptors.
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Affiliation(s)
- Graciela Pineyro
- Department of Pharmacology and Physiology, Faculty of Medicine, University of Montreal, Montreal, QC H3T 1J4, Canada; CHU Sainte-Justine research center, Montreal, QC H3T 1C5, Canada
| | - Karim Nagi
- College of Medicine, QU Health, Qatar University, Doha, Qatar.
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10
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Differential Distribution of Ca 2+ Channel Subtypes at Retinofugal Synapses. eNeuro 2020; 7:ENEURO.0293-20.2020. [PMID: 33097488 PMCID: PMC7768275 DOI: 10.1523/eneuro.0293-20.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 10/06/2020] [Accepted: 10/20/2020] [Indexed: 02/06/2023] Open
Abstract
Retinofugal synapses serve as models for understanding how sensory signals from the periphery are relayed to the brain. Past studies have focused primarily on understanding the postsynaptic glutamatergic receptor subtypes involved in signal transmission, but the mechanisms underlying glutamate release at presynaptic retinal terminals remains largely unknown. Here we explored how different calcium (Ca2+) channel subtypes regulate glutamatergic excitatory synaptic transmission in two principal retinorecipient targets, the dorsal lateral geniculate nucleus (dLGN) and superior colliculus (SC) of the mouse. We used an in vitro slice preparation to record the synaptic responses of dLGN and SC neurons evoked by the electrical stimulation of optic tract (OT) fibers before and during the application of selective Ca2+ channel blockers. We found that synaptic responses to paired or repetitive OT stimulation were highly sensitive to extracellular levels of Ca2+ and to selective antagonists of voltage gated Ca2+ channels, indicating that these channels regulate the presynaptic release of glutamate at retinal synapses in both dLGN and SC. Bath application of selective Ca2+ channel blockers revealed that P/Q-type Ca2+ channels primarily operate to regulate glutamate release at retinal synapses in dLGN, while N-type Ca2+ channels dominate release in the SC.
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11
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Salarinasab S, Salimi L, Alidadiani N, Shokrollahi E, Arzhanga P, Karbasforush S, Marofi F, Nasirzadeh M, Rahbarghazi R, Nourazarian A, Nikanfar M. Interaction of opioid with insulin/IGFs signaling in Alzheimer's disease. J Mol Neurosci 2020; 70:819-834. [PMID: 32026387 DOI: 10.1007/s12031-020-01478-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 01/09/2020] [Indexed: 12/21/2022]
Abstract
Alzheimer's disease is associated with biochemical and histopathological changes characterized by molecular abnormalities. Due to the lack of effective treatments for Alzheimer's disease, many attempts have been made to find potential therapies to reduce or even return neuronal loss after disease initiation. Alzheimer's disease is also touted as type III diabetes, showing an association with insulin signaling. The large distribution of the insulin receptor on the cell surface and its regulatory role in the central nervous system suggests that the pathogenesis of Alzheimer's disease could be ascribed to insulin signaling. The interference of opioids, such as morphine with insulin signaling pathways, is thought to occur via direct crosstalk between the signaling pathways of the insulin receptor and the mu-opioid receptor. In this review article, we discuss the possible crosstalk between the mu-opioid receptor and insulin signaling pathways. The association of these two signaling pathways with Alzheimer's disease is also debated.
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Affiliation(s)
- Sadegh Salarinasab
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Science, Kerman, Iran
| | - Leila Salimi
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Neda Alidadiani
- Department of Cardiac Surgery, Friedrich-Alexander-University Erlangen-Nürnberg, Krankenhausstr. 12, 91054, Erlangen, Germany
| | - Elhameh Shokrollahi
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Science, Kerman, Iran
| | - Pishva Arzhanga
- Department of Biochemistry and Diet Therapy, Faculty of Nutrition and Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Saedeh Karbasforush
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Science, Kerman, Iran
| | - Faroogh Marofi
- Department of Hematology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mahdieh Nasirzadeh
- Department of Biochemistry, Faculty of Medicine, Urmia University of Medical Sciences, Urmia, Iran
| | - Reza Rahbarghazi
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
- Department of Applied Cell Sciences, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Imam Reza St, Golgasht St, Tabriz, 51666-14756, Iran.
| | - Alireza Nourazarian
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Science, Kerman, Iran.
- Department of Biochemistry and Clinical Laboratories, Faculty of Medicine, Tabriz University of Medical Sciences, Golgasht St, Tabriz, 51666-16471, Iran.
| | - Masoud Nikanfar
- Department of Neurology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
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12
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Zheng Y, Obeng S, Reinecke BA, Chen C, Phansalkar PS, Walentiny DM, Gerk PM, Liu-Chen LY, Selley DE, Beardsley PM, Zhang Y. Pharmacological characterization of 17-cyclopropylmethyl-3,14-dihydroxy-4,5-epoxy-6-[(3'-fluoro-4'-pyridyl)acetamido]morphinan (NFP) as a dual selective MOR/KOR ligand with potential applications in treating opioid use disorder. Eur J Pharmacol 2019; 865:172812. [PMID: 31743739 PMCID: PMC6914219 DOI: 10.1016/j.ejphar.2019.172812] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 11/07/2019] [Accepted: 11/14/2019] [Indexed: 01/16/2023]
Abstract
For thousands of years opioids have been the first-line treatment option for pain management. However, the tolerance and addiction potential of opioids limit their applications in clinic. NFP, a MOR/KOR dual-selective opioid antagonist, was identified as a ligand that significantly antagonized the antinociceptive effects of morphine with lesser withdrawal effects than naloxone at similar doses. To validate the potential application of NFP in opioid addiction treatment, a series of in vitro and in vivo assays were conducted to further characterize its pharmacological profile. In calcium mobilization assays and MOR internalization studies, NFP showed the apparent capacity to antagonize DAMGO-induced calcium flux and etorphine-induced MOR internalization. In contrast to the opioid agonists DAMGO and morphine, cells pretreated with NFP did not show apparent desensitization and down regulation of the MOR. Though in vitro bidirectional transport studies showed that NFP might be a P-gp substrate, in warm-water tail-withdrawal assays it was able to antagonize the antinociceptive effects of morphine indicating its potential central nervous system activity. Overall these results suggest that NFP is a promising dual selective opioid antagonist that may have the potential to be used therapeutically in opioid use disorder treatment.
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MESH Headings
- Analgesics, Opioid/pharmacology
- Animals
- Biological Transport
- CHO Cells
- Caco-2 Cells
- Calcium/metabolism
- Cell Line, Tumor
- Cricetulus
- Enkephalin, Ala(2)-MePhe(4)-Gly(5)-/pharmacology
- Humans
- Ligands
- Male
- Mice, Inbred C57BL
- Morphinans/pharmacology
- Narcotic Antagonists/pharmacology
- Opioid-Related Disorders/drug therapy
- Receptors, Opioid, kappa/agonists
- Receptors, Opioid, kappa/antagonists & inhibitors
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/antagonists & inhibitors
- Receptors, Opioid, mu/genetics
- Receptors, Opioid, mu/metabolism
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Affiliation(s)
- Yi Zheng
- Department of Medicinal Chemistry, Virginia Commonwealth University, 800 E. Leigh Street, Richmond, VA, 23298, United States
| | - Samuel Obeng
- Department of Medicinal Chemistry, Virginia Commonwealth University, 800 E. Leigh Street, Richmond, VA, 23298, United States
| | - Bethany A Reinecke
- Department of Medicinal Chemistry, Virginia Commonwealth University, 800 E. Leigh Street, Richmond, VA, 23298, United States
| | - Chongguang Chen
- Department of Pharmacology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, United States
| | - Palak S Phansalkar
- Department of Pharmaceutics, Virginia Commonwealth University, 410 North 12th Street, Richmond, VA, 23298, United States
| | - David M Walentiny
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, 1112 East Clay Street, Richmond, VA, 23298, United States
| | - Phillip M Gerk
- Department of Pharmaceutics, Virginia Commonwealth University, 410 North 12th Street, Richmond, VA, 23298, United States
| | - Lee-Yuan Liu-Chen
- Department of Pharmacology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, United States
| | - Dana E Selley
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, 1112 East Clay Street, Richmond, VA, 23298, United States
| | - Patrick M Beardsley
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, 1112 East Clay Street, Richmond, VA, 23298, United States; Center for Biomarker Research and Precision Medicine, Virginia Commonwealth University, 1112 East Clay Street, Richmond, VA, 23298, United States
| | - Yan Zhang
- Department of Medicinal Chemistry, Virginia Commonwealth University, 800 E. Leigh Street, Richmond, VA, 23298, United States.
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Gandini MA, Souza IA, Raval D, Xu J, Pan YX, Zamponi GW. Differential regulation of Cav2.2 channel exon 37 variants by alternatively spliced μ-opioid receptors. Mol Brain 2019; 12:98. [PMID: 31775826 PMCID: PMC6880636 DOI: 10.1186/s13041-019-0524-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 11/14/2019] [Indexed: 12/15/2022] Open
Abstract
We have examined the regulation of mutually exclusive Cav2.2 exon 37a and b variants by the mouse μ-opioid receptor (mMOR) C-terminal splice variants 1, 1C and 1O in tsA-201 cells. Electrophysiological analyses revealed that both channel isoforms exhibit DAMGO-induced voltage-dependent (Gβγ-mediated) inhibition and its recovery by voltage pre-pulses, as well as a voltage-independent component. However, the two channel isoforms differ in their relative extent of voltage-dependent and independent inhibition, with Cav2.2-37b showing significantly more voltage-dependent inhibition upon activation of the three mMOR receptors studied. In addition, coexpression of either mMOR1 or mMOR1C results in an agonist-independent reduction in the peak current density of Cav2.2-37a channels, whereas the peak current density of Cav2.2-37b does not appear to be affected. Interestingly, this decrease is not due to an effect on channel expression at the plasma membrane, as demonstrated by biotinylation experiments. We further examined the mechanism underlying the agonist-independent modulation of Cav2.2-37a by mMOR1C. Incubation of cells with pertussis toxin did not affect the mMOR1C mediated inhibition of Cav2.2-37a currents, indicating a lack of involvement of Gi/o signaling. However, when a Src tyrosine kinase inhibitor was applied, the effect of mMOR1C was lost. Moreover, when we recorded currents using a Cav2.2-37a mutant in which tyrosine 1747 was replaced with phenylalanine (Y1747F), the agonist independent effects of mMOR1C were abolished. Altogether our findings show that Cav2.2-37a and Cav2.2-37b isoforms are subject to differential regulation by C-terminal splice variants of mMORs, and that constitutive mMOR1C activity and downstream tyrosine kinase activity exert a selective inhibition of the Cav2.2-37a splice variant, an N-type channel isoform that is highly enriched in nociceptors. Our study provides new insights into the roles of the MOR full-length C-terminal variants in modulating Cav2.2 channel isoform activities.
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Affiliation(s)
- Maria A Gandini
- Department of Physiology and Pharmacology, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Ivana A Souza
- Department of Physiology and Pharmacology, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Dvij Raval
- Department of Physiology and Pharmacology, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Jin Xu
- Department of Neurology and the Molecular Pharmacology Program, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Ying-Xian Pan
- Department of Neurology and the Molecular Pharmacology Program, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Gerald W Zamponi
- Department of Physiology and Pharmacology, Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
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Listos J, Łupina M, Talarek S, Mazur A, Orzelska-Górka J, Kotlińska J. The Mechanisms Involved in Morphine Addiction: An Overview. Int J Mol Sci 2019; 20:ijms20174302. [PMID: 31484312 PMCID: PMC6747116 DOI: 10.3390/ijms20174302] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 08/23/2019] [Accepted: 08/29/2019] [Indexed: 12/22/2022] Open
Abstract
Opioid use disorder is classified as a chronic recurrent disease of the central nervous system (CNS) which leads to personality disorders, co-morbidities and premature death. It develops as a result of long-term administration of various abused substances, along with morphine. The pharmacological action of morphine is associated with its stimulation of opioid receptors. Opioid receptors are a group of G protein-coupled receptors and activation of these receptors by ligands induces significant molecular changes inside the cell, such as an inhibition of adenylate cyclase activity, activation of potassium channels and reductions of calcium conductance. Recent data indicate that other signalling pathways also may be involved in morphine activity. Among these are phospholipase C, mitogen-activated kinases (MAP kinases) or β-arrestin. The present review focuses on major mechanisms which currently are considered as essential in morphine activity and dependence and may be important for further studies.
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Affiliation(s)
- Joanna Listos
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodzki 4a St., 20-093 Lublin, Poland.
| | - Małgorzata Łupina
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodzki 4a St., 20-093 Lublin, Poland.
| | - Sylwia Talarek
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodzki 4a St., 20-093 Lublin, Poland.
| | - Antonina Mazur
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodzki 4a St., 20-093 Lublin, Poland.
| | - Jolanta Orzelska-Górka
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodzki 4a St., 20-093 Lublin, Poland.
| | - Jolanta Kotlińska
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodzki 4a St., 20-093 Lublin, Poland.
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15
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Ferré G, Czaplicki G, Demange P, Milon A. Structure and dynamics of dynorphin peptide and its receptor. VITAMINS AND HORMONES 2019; 111:17-47. [DOI: 10.1016/bs.vh.2019.05.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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16
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Abstract
The nociceptin/orphanin FQ (N/OFQ) peptide (NOP) receptor is a G protein-coupled receptor with wide distribution throughout the peripheral and central nervous system. Similar to other opioid receptors, NOP receptors couple to intracellular second messengers and regulatory proteins to affect biological systems. In this chapter, we review the current literature for NOP signaling cascades including their role as classic GPCRs, the investigation of their kinase and arrestin signaling pathways, and the importance of examining biased signaling to critically evaluate the therapeutic potential of novel NOP agonists.
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Affiliation(s)
- Kyle E Parker
- Department of Anesthesiology, Division of Basic Research, Washington University School of Medicine, St. Louis, MO, USA
| | - Michael R Bruchas
- Department of Anesthesiology and Pain Medicine, Center for Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, WA, USA.
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17
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Abstract
Modulation of neurotransmitter exocytosis by activated Gi/o coupled G-protein coupled receptors (GPCRs) is a universal regulatory mechanism used both to avoid overstimulation and to influence circuitry. One of the known modulation mechanisms is the interaction between Gβγ and the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNAREs). There are 5 Gβ and 12 Gγ subunits, but specific Gβγs activated by a given GPCR and the specificity to effectors, such as SNARE, in vivo are not known. Although less studied, Gβγ binding to the exocytic fusion machinery (i.e. SNARE) provides a more direct regulatory mechanism for neurotransmitter release. Here, we review some recent insights in the architecture of the synaptic terminal, modulation of synaptic transmission, and implications of G protein modulation of synaptic transmission in diseases. Numerous presynaptic proteins are involved in the architecture of synaptic terminals, particularly the active zone, and their importance in the regulation of exocytosis is still not completely understood. Further understanding of the Gβγ-SNARE interaction and the architecture and mechanisms of exocytosis may lead to the discovery of novel therapeutic targets to help patients with various disorders such as hypertension, attention-deficit/hyperactivity disorder, post-traumatic stress disorder, and acute/chronic pain.
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Affiliation(s)
- Yun Young Yim
- Department of Pharmacology, Vanderbilt University, Nashville 37232-6600, TN, United States
| | - Zack Zurawski
- Department of Pharmacology, Vanderbilt University, Nashville 37232-6600, TN, United States
| | - Heidi Hamm
- Department of Pharmacology, Vanderbilt University, Nashville 37232-6600, TN, United States.
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18
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Akbergenova Y, Cunningham KL, Zhang YV, Weiss S, Littleton JT. Characterization of developmental and molecular factors underlying release heterogeneity at Drosophila synapses. eLife 2018; 7:38268. [PMID: 29989549 PMCID: PMC6075867 DOI: 10.7554/elife.38268] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 06/30/2018] [Indexed: 12/14/2022] Open
Abstract
Neurons communicate through neurotransmitter release at specialized synaptic regions known as active zones (AZs). Using biosensors to visualize single synaptic vesicle fusion events at Drosophila neuromuscular junctions, we analyzed the developmental and molecular determinants of release probability (Pr) for a defined connection with ~300 AZs. Pr was heterogeneous but represented a stable feature of each AZ. Pr remained stable during high frequency stimulation and retained heterogeneity in mutants lacking the Ca2+ sensor Synaptotagmin 1. Pr correlated with both presynaptic Ca2+ channel abundance and Ca2+ influx at individual release sites. Pr heterogeneity also correlated with glutamate receptor abundance, with high Pr connections developing receptor subtype segregation. Intravital imaging throughout development revealed that AZs acquire high Pr during a multi-day maturation period, with Pr heterogeneity largely reflecting AZ age. The rate of synapse maturation was activity-dependent, as both increases and decreases in neuronal activity modulated glutamate receptor field size and segregation. To send a message to its neighbor, a neuron releases chemicals called neurotransmitters into the gap – or synapse – between them. The neurotransmitter molecules bind to proteins on the receiver neuron called receptors. But what causes the sender neuron to release neurotransmitter in the first place? The process starts when an electrical impulse called an action potential arrives at the sender cell. Its arrival causes channels in the membrane of the sender neuron to open, so that calcium ions flood into the cell. The calcium ions interact with packages of neurotransmitter molecules, known as synaptic vesicles. This causes some of the vesicles to empty their contents into the synapse. But this process is not particularly reliable. Only a small fraction of action potentials cause vesicles to fuse with the synaptic membrane. How likely this is to occur varies greatly between neurons, and even between synapses formed by the same neuron. Synapses that are likely to release neurotransmitter are said to be strong. They are good at passing messages from the sender neuron to the receiver. Synapses with a low probability of release are said to be weak. But what exactly differs between strong and weak synapses? Akbergenova et al. studied synapses between motor neurons and muscle cells in the fruit fly Drosophila. Each motor neuron forms several hundred synapses. Some of these synapses are 50 times more likely to release neurotransmitter than others. Using calcium imaging and genetics, Akbergenova et al. showed that sender cells at strong synapses have more calcium channels than sender cells at weak synapses. The subtypes and arrangement of receptor proteins also differ between the receiver neurons of strong versus weak synapses. Finally, studies in larvae revealed that newly formed synapses all start out weak and then gradually become stronger. How fast this strengthening occurs depends on how active the neuron at the synapse is. This study has shown, in unprecedented detail, key molecular factors that make some fruit fly synapses more likely to release neurotransmitter than others. Many proteins at synapses of mammals resemble those at fruit fly synapses. This means that similar factors may also explain differences in synaptic strength in the mammalian brain. Changes in the strength of synapses underlie the ability to learn. Furthermore, many neurological and psychiatric disorders result from disruption of synapses. Understanding the molecular basis of synapses will thus provide clues to the origins of certain brain diseases.
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Affiliation(s)
- Yulia Akbergenova
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Karen L Cunningham
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
| | - Yao V Zhang
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Shirley Weiss
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - J Troy Littleton
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
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19
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Grzelka K, Kurowski P, Gawlak M, Szulczyk P. Noradrenaline Modulates the Membrane Potential and Holding Current of Medial Prefrontal Cortex Pyramidal Neurons via β 1-Adrenergic Receptors and HCN Channels. Front Cell Neurosci 2017; 11:341. [PMID: 29209170 PMCID: PMC5701640 DOI: 10.3389/fncel.2017.00341] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 10/16/2017] [Indexed: 12/27/2022] Open
Abstract
The medial prefrontal cortex (mPFC) receives dense noradrenergic projections from the locus coeruleus. Adrenergic innervation of mPFC pyramidal neurons plays an essential role in both physiology (control of memory formation, attention, working memory, and cognitive behavior) and pathophysiology (attention deficit hyperactivity disorder, posttraumatic stress disorder, cognitive deterioration after traumatic brain injury, behavioral changes related to addiction, Alzheimer’s disease and depression). The aim of this study was to elucidate the mechanism responsible for adrenergic receptor-mediated control of the resting membrane potential in layer V mPFC pyramidal neurons. The membrane potential or holding current of synaptically isolated layer V mPFC pyramidal neurons was recorded in perforated-patch and classical whole-cell configurations in slices from young rats. Application of noradrenaline (NA), a neurotransmitter with affinity for all types of adrenergic receptors, evoked depolarization or inward current in the tested neurons irrespective of whether the recordings were performed in the perforated-patch or classical whole-cell configuration. The effect of noradrenaline depended on β1- and not α1- or α2-adrenergic receptor stimulation. Activation of β1-adrenergic receptors led to an increase in inward Na+ current through hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, which carry a mixed Na+/K+ current. The protein kinase A- and C-, glycogen synthase kinase-3β- and tyrosine kinase-linked signaling pathways were not involved in the signal transduction between β1-adrenergic receptors and HCN channels. The transduction system operated in a membrane-delimited fashion and involved the βγ subunit of G-protein. Thus, noradrenaline controls the resting membrane potential and holding current in mPFC pyramidal neurons through β1-adrenergic receptors, which in turn activate HCN channels via a signaling pathway involving the βγ subunit.
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Affiliation(s)
- Katarzyna Grzelka
- Laboratory of Physiology and Pathophysiology, Centre for Preclinical Research and Technology, Medical University of Warsaw, Warsaw, Poland
| | - Przemysław Kurowski
- Laboratory of Physiology and Pathophysiology, Centre for Preclinical Research and Technology, Medical University of Warsaw, Warsaw, Poland
| | - Maciej Gawlak
- Laboratory of Physiology and Pathophysiology, Centre for Preclinical Research and Technology, Medical University of Warsaw, Warsaw, Poland
| | - Paweł Szulczyk
- Laboratory of Physiology and Pathophysiology, Centre for Preclinical Research and Technology, Medical University of Warsaw, Warsaw, Poland
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20
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Anti-nociceptive effect of patchouli alcohol: Involving attenuation of cyclooxygenase 2 and modulation of mu-opioid receptor. Chin J Integr Med 2017; 25:454-461. [PMID: 28795389 DOI: 10.1007/s11655-017-2952-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Indexed: 12/31/2022]
Abstract
OBJECTIVE To explore the anti-nociceptive effect of patchouli alcohol (PA), the essential oil isolated from Pogostemon cablin (Blanco) Bent, and determine the mechanism in molecular levels. METHODS The acetic acid-induced writhing test and formalin-induced plantar injection test in mice were employed to confirm the effect in vivo. Intracellular calcium ion was imaged to verify PA on mu-opioid receptor (MOR). Cyclooxygenase 2 (COX2) and MOR of mouse brain were expressed for determination of PA's target. Cellular experiments were carried out to find out COX2 and MOR expression induced by PA. RESULTS PA significantly reduced latency period of visceral pain and writhing induced by acetic acid saline solution (P<0.01) and allodynia after intra-plantar formalin (P<0.01) in mice. PA also up-regulated COX2 mRNA and protein (P<0.05) with a down-regulation of MOR (P<0.05) both in in vivo and in vitro experiments, which devote to the analgesic effect of PA. A decrease in the intracellular calcium level (P<0.05) induced by PA may play an important role in its anti-nociceptive effect. PA showed the characters of enhancing the MOR expression and reducing the intracellular calcium ion similar to opioid effect. CONCLUSIONS Both COX2 and MOR are involved in the mechanism of PA's anti-nociceptive effect, and the up-regulation of the receptor expression and the inhibition of intracellular calcium are a new perspective to PA's effect on MOR.
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21
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Toll L, Bruchas MR, Calo' G, Cox BM, Zaveri NT. Nociceptin/Orphanin FQ Receptor Structure, Signaling, Ligands, Functions, and Interactions with Opioid Systems. Pharmacol Rev 2016; 68:419-57. [PMID: 26956246 PMCID: PMC4813427 DOI: 10.1124/pr.114.009209] [Citation(s) in RCA: 208] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The NOP receptor (nociceptin/orphanin FQ opioid peptide receptor) is the most recently discovered member of the opioid receptor family and, together with its endogenous ligand, N/OFQ, make up the fourth members of the opioid receptor and opioid peptide family. Because of its more recent discovery, an understanding of the cellular and behavioral actions induced by NOP receptor activation are less well developed than for the other members of the opioid receptor family. All of these factors are important because NOP receptor activation has a clear modulatory role on mu opioid receptor-mediated actions and thereby affects opioid analgesia, tolerance development, and reward. In addition to opioid modulatory actions, NOP receptor activation has important effects on motor function and other physiologic processes. This review discusses how NOP pharmacology intersects, contrasts, and interacts with the mu opioid receptor in terms of tertiary structure and mechanism of receptor activation; location of receptors in the central nervous system; mechanisms of desensitization and downregulation; cellular actions; intracellular signal transduction pathways; and behavioral actions with respect to analgesia, tolerance, dependence, and reward. This is followed by a discussion of the agonists and antagonists that have most contributed to our current knowledge. Because NOP receptors are highly expressed in brain and spinal cord and NOP receptor activation sometimes synergizes with mu receptor-mediated actions and sometimes opposes them, an understanding of NOP receptor pharmacology in the context of these interactions with the opioid receptors will be crucial to the development of novel therapeutics that engage the NOP receptor.
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Affiliation(s)
- Lawrence Toll
- Torrey Pines Institute for Molecular Studies, Port St. Lucie, Florida (L.T.); Departments of Anesthesiology, and Neuroscience, Washington University School of Medicine, St. Louis, Missouri (M.R.B.); Section of Pharmacology, Department of Medical Science, and National Institute of Neurosciences, University of Ferrara, Ferrara, Italy (G.C.); Professor of Pharmacology & Neuroscience, Uniformed Services University, Bethesda, Maryland (B.M.C.); and Astraea Therapeutics, LLC, Mountain View, California (N.T.Z.)
| | - Michael R Bruchas
- Torrey Pines Institute for Molecular Studies, Port St. Lucie, Florida (L.T.); Departments of Anesthesiology, and Neuroscience, Washington University School of Medicine, St. Louis, Missouri (M.R.B.); Section of Pharmacology, Department of Medical Science, and National Institute of Neurosciences, University of Ferrara, Ferrara, Italy (G.C.); Professor of Pharmacology & Neuroscience, Uniformed Services University, Bethesda, Maryland (B.M.C.); and Astraea Therapeutics, LLC, Mountain View, California (N.T.Z.)
| | - Girolamo Calo'
- Torrey Pines Institute for Molecular Studies, Port St. Lucie, Florida (L.T.); Departments of Anesthesiology, and Neuroscience, Washington University School of Medicine, St. Louis, Missouri (M.R.B.); Section of Pharmacology, Department of Medical Science, and National Institute of Neurosciences, University of Ferrara, Ferrara, Italy (G.C.); Professor of Pharmacology & Neuroscience, Uniformed Services University, Bethesda, Maryland (B.M.C.); and Astraea Therapeutics, LLC, Mountain View, California (N.T.Z.)
| | - Brian M Cox
- Torrey Pines Institute for Molecular Studies, Port St. Lucie, Florida (L.T.); Departments of Anesthesiology, and Neuroscience, Washington University School of Medicine, St. Louis, Missouri (M.R.B.); Section of Pharmacology, Department of Medical Science, and National Institute of Neurosciences, University of Ferrara, Ferrara, Italy (G.C.); Professor of Pharmacology & Neuroscience, Uniformed Services University, Bethesda, Maryland (B.M.C.); and Astraea Therapeutics, LLC, Mountain View, California (N.T.Z.)
| | - Nurulain T Zaveri
- Torrey Pines Institute for Molecular Studies, Port St. Lucie, Florida (L.T.); Departments of Anesthesiology, and Neuroscience, Washington University School of Medicine, St. Louis, Missouri (M.R.B.); Section of Pharmacology, Department of Medical Science, and National Institute of Neurosciences, University of Ferrara, Ferrara, Italy (G.C.); Professor of Pharmacology & Neuroscience, Uniformed Services University, Bethesda, Maryland (B.M.C.); and Astraea Therapeutics, LLC, Mountain View, California (N.T.Z.)
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22
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Zhou Y, Greka A. Calcium-permeable ion channels in the kidney. Am J Physiol Renal Physiol 2016; 310:F1157-67. [PMID: 27029425 DOI: 10.1152/ajprenal.00117.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 03/29/2016] [Indexed: 02/07/2023] Open
Abstract
Calcium ions (Ca(2+)) are crucial for a variety of cellular functions. The extracellular and intracellular Ca(2+) concentrations are thus tightly regulated to maintain Ca(2+) homeostasis. The kidney, one of the major organs of the excretory system, regulates Ca(2+) homeostasis by filtration and reabsorption. Approximately 60% of the Ca(2+) in plasma is filtered, and 99% of that is reabsorbed by the kidney tubules. Ca(2+) is also a critical signaling molecule in kidney development, in all kidney cellular functions, and in the emergence of kidney diseases. Recently, studies using genetic and molecular biological approaches have identified several Ca(2+)-permeable ion channel families as important regulators of Ca(2+) homeostasis in kidney. These ion channel families include transient receptor potential channels (TRP), voltage-gated calcium channels, and others. In this review, we provide a brief and systematic summary of the expression, function, and pathological contribution for each of these Ca(2+)-permeable ion channels. Moreover, we discuss their potential as future therapeutic targets.
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Affiliation(s)
- Yiming Zhou
- Department of Medicine and Glom-NExT Center for Glomerular Kidney Disease and Novel Experimental Therapeutics, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts; and
| | - Anna Greka
- Department of Medicine and Glom-NExT Center for Glomerular Kidney Disease and Novel Experimental Therapeutics, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts; and The Broad Institute of MIT and Harvard, Cambridge, Massachusetts
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Abstract
A central theme in the quest to unravel the genetic basis of epilepsy has been the effort to elucidate the roles played by inherited defects in ion channels. The ubiquitous expression of voltage-gated calcium channels (VGCCs) throughout the central nervous system (CNS), along with their involvement in fundamental processes, such as neuronal excitability and synaptic transmission, has made them attractive candidates. Recent insights provided by the identification of mutations in the P/Q-type calcium channel in humans and rodents with epilepsy and the finding of thalamic T-type calcium channel dysfunction in the absence of seizures have raised expectations of a causal role of calcium channels in the polygenic inheritance of idiopathic epilepsy. In this review, we consider how genetic variation in neuronal VGCCs may influence the development of epilepsy.
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Affiliation(s)
- Sanjeev Rajakulendran
- UCL-Institute of Neurology, MRC Centre for Neuromuscular Diseases, Queen Square, London WC1N 3BG, United Kingdom
| | - Michael G Hanna
- UCL-Institute of Neurology, MRC Centre for Neuromuscular Diseases, Queen Square, London WC1N 3BG, United Kingdom
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24
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Gaval-Cruz M, Goertz RB, Puttick DJ, Bowles DE, Meyer RC, Hall RA, Ko D, Paladini CA, Weinshenker D. Chronic loss of noradrenergic tone produces β-arrestin2-mediated cocaine hypersensitivity and alters cellular D2 responses in the nucleus accumbens. Addict Biol 2016; 21:35-48. [PMID: 25123018 DOI: 10.1111/adb.12174] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cocaine blocks plasma membrane monoamine transporters and increases extracellular levels of dopamine (DA), norepinephrine (NE) and serotonin (5-HT). The addictive properties of cocaine are mediated primarily by DA, while NE and 5-HT play modulatory roles. Chronic inhibition of dopamine β-hydroxylase (DBH), which converts DA to NE, increases the aversive effects of cocaine and reduces cocaine use in humans, and produces behavioral hypersensitivity to cocaine and D2 agonism in rodents, but the underlying mechanism is unknown. We found a decrease in β-arrestin2 (βArr2) in the nucleus accumbens (NAc) following chronic genetic or pharmacological DBH inhibition, and overexpression of βArr2 in the NAc normalized cocaine-induced locomotion in DBH knockout (Dbh -/-) mice. The D2/3 agonist quinpirole decreased excitability in NAc medium spiny neurons (MSNs) from control, but not Dbh -/- animals, where instead there was a trend for an excitatory effect. The Gαi inhibitor NF023 abolished the quinpirole-induced decrease in excitability in control MSNs, but had no effect in Dbh -/- MSNs, whereas the Gαs inhibitor NF449 restored the ability of quinpirole to decrease excitability in Dbh -/- MSNs, but had no effect in control MSNs. These results suggest that chronic loss of noradrenergic tone alters behavioral responses to cocaine via decreases in βArr2 and cellular responses to D2/D3 activation, potentially via changes in D2-like receptor G-protein coupling in NAc MSNs.
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Affiliation(s)
- Meriem Gaval-Cruz
- Department of Human Genetics; Emory University School of Medicine; Atlanta GA USA
| | - Richard B. Goertz
- Department of Biology; Neurosciences Institute; University of Texas at San Antonio; San Antonio TX USA
| | - Daniel J. Puttick
- Department of Human Genetics; Emory University School of Medicine; Atlanta GA USA
| | - Dawn E. Bowles
- Department of Surgery; Duke University School of Medicine; Durham NC USA
| | - Rebecca C. Meyer
- Department of Pharmacology; Emory University School of Medicine; Atlanta GA USA
| | - Randy A. Hall
- Department of Pharmacology; Emory University School of Medicine; Atlanta GA USA
| | - Daijin Ko
- Department of Management Science and Statistics; University of Texas at San Antonio; San Antonio TX USA
| | - Carlos A. Paladini
- Department of Biology; Neurosciences Institute; University of Texas at San Antonio; San Antonio TX USA
| | - David Weinshenker
- Department of Human Genetics; Emory University School of Medicine; Atlanta GA USA
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25
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Abstract
In excitable cells, ion channels are frequently challenged by repetitive stimuli, and their responses shape cellular behavior by regulating the duration and termination of bursts of action potentials. We have investigated the behavior of Shaker family voltage-gated potassium (Kv) channels subjected to repetitive stimuli, with a particular focus on Kv1.2. Genetic deletion of this subunit results in complete mortality within 2 weeks of birth in mice, highlighting a critical physiological role for Kv1.2. Kv1.2 channels exhibit a unique property described previously as "prepulse potentiation," in which activation by a depolarizing step facilitates activation in a subsequent pulse. In this study, we demonstrate that this property enables Kv1.2 channels to exhibit use-dependent activation during trains of very brief depolarizations. Also, Kv subunits usually assemble into heteromeric channels in the central nervous system, generating diversity of function and sensitivity to signaling mechanisms. We demonstrate that other Kv1 channel types do not exhibit use-dependent activation, but this property is conferred in heteromeric channel complexes containing even a single Kv1.2 subunit. This regulatory mechanism is observed in mammalian cell lines as well as primary cultures of hippocampal neurons. Our findings illustrate that use-dependent activation is a unique property of Kv1.2 that persists in heteromeric channel complexes and may influence function of hippocampal neurons.
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Agosti F, López Soto EJ, Cabral A, Castrogiovanni D, Schioth HB, Perelló M, Raingo J. Melanocortin 4 receptor activation inhibits presynaptic N-type calcium channels in amygdaloid complex neurons. Eur J Neurosci 2014; 40:2755-65. [PMID: 24943127 DOI: 10.1111/ejn.12650] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 04/30/2014] [Accepted: 05/05/2014] [Indexed: 12/22/2022]
Abstract
The melanocortin 4 receptor (MC4R) is a G protein-coupled receptor involved in food intake and energy expenditure regulation. MC4R activation modifies neuronal activity but the molecular mechanisms by which this regulation occurs remain unclear. Here, we tested the hypothesis that MC4R activation regulates the activity of voltage-gated calcium channels and, as a consequence, synaptic activity. We also tested whether the proposed effect occurs in the amygdala, a brain area known to mediate the anorexigenic actions of MC4R signaling. Using the patch-clamp technique, we found that the activation of MC4R with its agonist melanotan II specifically inhibited 34.5 ± 1.5% of N-type calcium currents in transiently transfected HEK293 cells. This inhibition was concentration-dependent, voltage-independent and occluded by the Gαs pathway inhibitor cholera toxin. Moreover, we found that melanotan II specifically inhibited 25.9 ± 2.0% of native N-type calcium currents and 55.4 ± 14.4% of evoked inhibitory postsynaptic currents in mouse cultured amygdala neurons. In vivo, we found that the MC4R agonist RO27-3225 increased the marker of cellular activity c-Fos in several components of the amygdala, whereas the N-type channel blocker ω conotoxin GVIA increased c-Fos expression exclusively in the central subdivision of the amygdala. Thus, MC4R specifically inhibited the presynaptic N-type channel subtype, and this inhibition may be important for the effects of melanocortin in the central subdivision of the amygdala.
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Affiliation(s)
- Francina Agosti
- Laboratory of Electrophysiology, Multidisciplinary Institute of Cell Biology (IMBICE), Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA), La Plata, Buenos Aires, Argentina
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27
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Seseña E, Vega R, Soto E. Activation of μ-opioid receptors inhibits calcium-currents in the vestibular afferent neurons of the rat through a cAMP dependent mechanism. Front Cell Neurosci 2014; 8:90. [PMID: 24734002 PMCID: PMC3973932 DOI: 10.3389/fncel.2014.00090] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2013] [Accepted: 03/11/2014] [Indexed: 11/24/2022] Open
Abstract
Opioid receptors are expressed in the vestibular endorgans (afferent neurons and hair cells) and are activated by the efferent system, which modulates the discharge of action potentials in vestibular afferent neurons (VANs). In mammals, VANs mainly express the μ opioid-receptor, but the function of this receptors activation and the cellular mechanisms by which they exert their actions in these neurons are poorly studied. To determine the actions of μ opioid receptor (MOR) and cell signaling mechanisms in VANs, we made perforated patch-clamp recordings of VANs that were obtained from postnatal days 7 to 10 (P7–10) rats and then maintained in primary culture. The MOR agonist [D-Ala2, N-Me-Phe4, Gly5-ol]-enkephalin (DAMGO) inhibited the total voltage-gated outward current; this effect was prevented by the perfusion of a Ca2+-free extracellular solution. We then studied the voltage-gated calcium current (Ica) and found that DAMGO Met-enkephalin or endomorphin-1 inhibited the ICa in a dose-response fashion. The effects of DAMGO were prevented by the MOR antagonist (CTAP) or by pertussis toxin (PTX). The use of specific calcium channel blockers showed that MOR activation inhibited T-, L- and N-type ICa. The use of various enzyme activators and inhibitors and of cAMP analogs allowed us to demonstrate that the MOR acts through a cAMP dependent signaling mechanism. In current clamp experiments, MOR activation increased the duration and decreased the amplitude of the action potentials and modulated the discharge produced by current injection. Pre-incubation with PTX occluded MOR activation effect. We conclude that MOR activation inhibits the T-, L- and N-type ICa through activation of a Gαi/o protein that involves a decrease in AC-cAMP-PKA activity. The modulation of ICa may have an impact on the synaptic integration, excitability, and neurotransmitter release from VANs.
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Affiliation(s)
- Emmanuel Seseña
- Instituto de Fisiología, Universidad Autónoma de Puebla Puebla, México
| | - Rosario Vega
- Instituto de Fisiología, Universidad Autónoma de Puebla Puebla, México
| | - Enrique Soto
- Instituto de Fisiología, Universidad Autónoma de Puebla Puebla, México
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28
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Kudryashova IV. Molecular mechanisms of short-term plasticity as a basis of frequency coding: The role of proteolytic systems. NEUROCHEM J+ 2014. [DOI: 10.1134/s1819712414010097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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29
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Hernández-González O, Hernández-Flores T, Prieto GA, Pérez-Burgos A, Arias-García MA, Galarraga E, Bargas J. Modulation of Ca2+-currents by sequential and simultaneous activation of adenosine A1 and A 2A receptors in striatal projection neurons. Purinergic Signal 2013; 10:269-81. [PMID: 24014158 PMCID: PMC4040173 DOI: 10.1007/s11302-013-9386-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 08/21/2013] [Indexed: 10/26/2022] Open
Abstract
D(1)- and D(2)-types of dopamine receptors are located separately in direct and indirect pathway striatal projection neurons (dSPNs and iSPNs). In comparison, adenosine A(1)-type receptors are located in both neuron classes, and adenosine A(2A)-type receptors show a preferential expression in iSPNs. Due to their importance for neuronal excitability, Ca(2+)-currents have been used as final effectors to see the function of signaling cascades associated with different G protein-coupled receptors. For example, among many other actions, D(1)-type receptors increase, while D(2)-type receptors decrease neuronal excitability by either enhancing or reducing, respectively, CaV1 Ca(2+)-currents. These actions occur separately in dSPNs and iSPNs. In the case of purinergic signaling, the actions of A(1)- and A(2A)-receptors have not been compared observing their actions on Ca(2+)-channels of SPNs as final effectors. Our hypotheses are that modulation of Ca(2+)-currents by A(1)-receptors occurs in both dSPNs and iSPNs. In contrast, iSPNs would exhibit modulation by both A(1)- and A2A-receptors. We demonstrate that A(1)-type receptors reduced Ca(2+)-currents in all SPNs tested. However, A(2A)-type receptors enhanced Ca(2+)-currents only in half tested neurons. Intriguingly, to observe the actions of A(2A)-type receptors, occupation of A(1)-type receptors had to occur first. However, A(1)-receptors decreased Ca(V)2 Ca(2+)-currents, while A(2A)-type receptors enhanced current through Ca(V)1 channels. Because these channels have opposing actions on cell discharge, these differences explain in part why iSPNs may be more excitable than dSPNs. It is demonstrated that intrinsic voltage-gated currents expressed in SPNs are effectors of purinergic signaling that therefore play a role in excitability.
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Affiliation(s)
- O. Hernández-González
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México [UNAM], P.O. Box: 70-253, Mexico City, México 04510
| | - T. Hernández-Flores
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México [UNAM], P.O. Box: 70-253, Mexico City, México 04510
| | - G. A. Prieto
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México [UNAM], P.O. Box: 70-253, Mexico City, México 04510
| | - A. Pérez-Burgos
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México [UNAM], P.O. Box: 70-253, Mexico City, México 04510
| | - M. A. Arias-García
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México [UNAM], P.O. Box: 70-253, Mexico City, México 04510
| | - E. Galarraga
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México [UNAM], P.O. Box: 70-253, Mexico City, México 04510
| | - J. Bargas
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México [UNAM], P.O. Box: 70-253, Mexico City, México 04510
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30
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Hansen PBL. Functional and pharmacological consequences of the distribution of voltage-gated calcium channels in the renal blood vessels. Acta Physiol (Oxf) 2013; 207:690-9. [PMID: 23351056 DOI: 10.1111/apha.12070] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 11/26/2012] [Accepted: 01/22/2013] [Indexed: 12/15/2022]
Abstract
Calcium channel blockers are widely used to treat hypertension because they inhibit voltage-gated calcium channels that mediate transmembrane calcium influx in, for example, vascular smooth muscle and cardiomyocytes. The calcium channel family consists of several subfamilies, of which the L-type is usually associated with vascular contractility. However, the L-, T- and P-/Q-types of calcium channels are present in the renal vasculature and are differentially involved in controlling vascular contractility, thereby contributing to regulation of kidney function and blood pressure. In the preglomerular vascular bed, all the three channel families are present. However, the T-type channel is the only channel in cortical efferent arterioles which is in contrast to the juxtamedullary efferent arteriole, and that leads to diverse functional effects of L- and T-type channel inhibition. Furthermore, by different mechanisms, T-type channels may contribute to both constriction and dilation of the arterioles. Finally, P-/Q-type channels are involved in the regulation of human intrarenal arterial contractility. The calcium blockers used in the clinic affect not only L-type but also P-/Q- and T-type channels. Therefore, the distinct effect obtained by inhibiting a given subtype or set of channels under experimental settings should be considered when choosing a calcium blocker for treatment. T-type channels seem to be crucial for regulating the GFR and the filtration fraction. Use of blockers is expected to lead to preferential efferent vasodilation, reduction of glomerular pressure and proteinuria. Therefore, renovascular T-type channels might provide novel therapeutic targets, and may have superior renoprotective effects compared to conventional calcium blockers.
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Affiliation(s)
- P. B. L. Hansen
- Department of Cardiovascular and Renal Research; Institute of Molecular Medicine; University of Southern Denmark; Odense; Denmark
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31
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Venom peptides as a rich source of cav2.2 channel blockers. Toxins (Basel) 2013; 5:286-314. [PMID: 23381143 PMCID: PMC3640536 DOI: 10.3390/toxins5020286] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 01/07/2013] [Accepted: 01/25/2013] [Indexed: 11/24/2022] Open
Abstract
Cav2.2 is a calcium channel subtype localized at nerve terminals, including nociceptive fibers, where it initiates neurotransmitter release. Cav2.2 is an important contributor to synaptic transmission in ascending pain pathways, and is up-regulated in the spinal cord in chronic pain states along with the auxiliary α2δ1 subunit. It is therefore not surprising that toxins that inhibit Cav2.2 are analgesic. Venomous animals, such as cone snails, spiders, snakes, assassin bugs, centipedes and scorpions are rich sources of remarkably potent and selective Cav2.2 inhibitors. However, side effects in humans currently limit their clinical use. Here we review Cav2.2 inhibitors from venoms and their potential as drug leads.
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32
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Zamponi GW, Currie KPM. Regulation of Ca(V)2 calcium channels by G protein coupled receptors. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1828:1629-43. [PMID: 23063655 DOI: 10.1016/j.bbamem.2012.10.004] [Citation(s) in RCA: 135] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 10/02/2012] [Accepted: 10/04/2012] [Indexed: 12/29/2022]
Abstract
Voltage gated calcium channels (Ca²⁺ channels) are key mediators of depolarization induced calcium influx into excitable cells, and thereby play pivotal roles in a wide array of physiological responses. This review focuses on the inhibition of Ca(V)2 (N- and P/Q-type) Ca²⁺-channels by G protein coupled receptors (GPCRs), which exerts important autocrine/paracrine control over synaptic transmission and neuroendocrine secretion. Voltage-dependent inhibition is the most widespread mechanism, and involves direct binding of the G protein βγ dimer (Gβγ) to the α1 subunit of Ca(V)2 channels. GPCRs can also recruit several other distinct mechanisms including phosphorylation, lipid signaling pathways, and channel trafficking that result in voltage-independent inhibition. Current knowledge of Gβγ-mediated inhibition is reviewed, including the molecular interactions involved, determinants of voltage-dependence, and crosstalk with other cell signaling pathways. A summary of recent developments in understanding the voltage-independent mechanisms prominent in sympathetic and sensory neurons is also included. This article is part of a Special Issue entitled: Calcium channels.
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Affiliation(s)
- Gerald W Zamponi
- Department of Physiology & Pharmacology, Hotchkiss Brain Institute, University of Calgary, Canada
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33
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Weiss S, Keren-Raifman T, Oz S, Ben Mocha A, Haase H, Dascal N. Modulation of distinct isoforms of L-type calcium channels by G(q)-coupled receptors in Xenopus oocytes: antagonistic effects of Gβγ and protein kinase C. Channels (Austin) 2012; 6:426-37. [PMID: 22990911 DOI: 10.4161/chan.22016] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
L-type voltage dependent Ca(2+) channels (L-VDCCs; Ca(v)1.2) are crucial in cardiovascular physiology. In heart and smooth muscle, hormones and transmitters operating via G(q) enhance L-VDCC currents via essential protein kinase C (PKC) involvement. Heterologous reconstitution studies in Xenopus oocytes suggested that PKC and G(q)-coupled receptors increased L-VDCC currents only in cardiac long N-terminus (NT) isoforms of α(1C), whereas known smooth muscle short-NT isoforms were inhibited by PKC and G(q) activators. We report a novel regulation of the long-NT α(1C) isoform by Gβγ. Gβγ inhibited whereas a Gβγ scavenger protein augmented the G(q)--but not phorbol ester-mediated enhancement of channel activity, suggesting that Gβγ acts upstream from PKC. In vitro binding experiments reveal binding of both Gβγ and PKC to α(1C)-NT. However, PKC modulation was not altered by mutations of multiple potential phosphorylation sites in the NT, and was attenuated by a mutation of C-terminally located serine S1928. The insertion of exon 9a in intracellular loop 1 rendered the short-NT α(1C) sensitive to PKC stimulation and to Gβγ scavenging. Our results suggest a complex antagonistic interplay between G(q)-activated PKC and Gβγ in regulation of L-VDCC, in which multiple cytosolic segments of α(1C) are involved.
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Affiliation(s)
- Sharon Weiss
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
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34
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Macedo-Junior SJ, Nascimento FP, Luiz-Cerutti M, Santos ARS. Role of pertussis toxin-sensitive G-protein, K+ channels, and voltage-gated Ca2+ channels in the antinociceptive effect of inosine. Purinergic Signal 2012; 9:51-8. [PMID: 22806273 DOI: 10.1007/s11302-012-9327-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 06/26/2012] [Indexed: 12/20/2022] Open
Abstract
Inosine is the first metabolite of adenosine. It exerts an antinociceptive effect by activating the adenosine A(1) and A(2A) receptors. We have previously demonstrated that inosine exhibits antinociceptive properties in acute and chronic mice models of nociception. The aim of this study was to investigate the involvement of pertussis toxin-sensitive G-protein-coupled receptors, as well as K(+) and Ca(2+) channels, in the antinociception promoted by inosine in the formalin test. Mice were pretreated with pertussis toxin (2.5 μg/site, i.t., an inactivator of G(i/0) protein); after 7 days, they received inosine (10 mg/kg, i.p.) or morphine (2.5 mg/kg, s.c., used as positive control) immediately before the formalin test. Another group of animals received tetraethylammonium (TEA) or 4-aminopyridine (4-AP) (1 μg/site, i.t., a non-specific voltage-gated K(+) channel blockers), apamin (50 ng/site, i.t., a small conductance Ca(2+)-activated K(+) channel blocker), charybdotoxin (250 pg/site, i.t., a large-conductance Ca(2+)-activated K(+) channel blocker), glibenclamide (100 μg/site, i.t., an ATP-sensitive K(+) channel blocker) or CaCl(2) (200 nmol/site, i.t.). Afterwards, the mice received inosine (10 mg/kg, i.p.), diclofenac (10 mg/kg, i.p., a positive control), or morphine (2.5 mg/kg, s.c., a positive control) immediately before the formalin test. The antinociceptive effect of inosine was reversed by the pre-administration of pertussis toxin (2.5 μg/site, i.t.), TEA, 4-aminopyridine, charybdotoxin, glibenclamide, and CaCl(2), but not apamin. Further, all K(+) channel blockers and CaCl(2) reversed the antinociception induced by diclofenac and morphine, respectively. Taken together, these data suggest that the antinociceptive effect of inosine is mediated, in part, by pertussis toxin-sensitive G-protein coupled receptors and the subsequent activation of voltage gated K(+) channel, large conductance Ca(2+)-activated and ATP-sensitive K(+) channels or inactivation of voltage-gated Ca(2+) channels. Finally, small conductance Ca(2+)-activated K(+) channels are not involved in the antinociceptive effect of inosine.
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Affiliation(s)
- Sérgio José Macedo-Junior
- Laboratório de Neurobiologia da Dor e Inflamação, Departamento de Ciências Fisiológicas, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Campus Trindade, Florianópolis, SC, 88040-900, Brazil
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35
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A novel series of pyrazolylpiperidine N-type calcium channel blockers. Bioorg Med Chem Lett 2012; 22:4080-3. [DOI: 10.1016/j.bmcl.2012.04.075] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2012] [Revised: 04/11/2012] [Accepted: 04/16/2012] [Indexed: 11/19/2022]
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36
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Endoh T, Nobushima H, Tazaki M. Neuropeptide Y modulates calcium channels in hamster submandibular ganglion neurons. Neurosci Res 2012; 73:275-81. [PMID: 22613697 DOI: 10.1016/j.neures.2012.05.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 05/02/2012] [Accepted: 05/02/2012] [Indexed: 11/28/2022]
Abstract
It is established that neuropeptide Y (NPY) is a transmitter of parasympathetic secretory impulses in submandibular gland. The neuropeptides substance P, vasoactive intestinal peptide (VIP) and calcitonin gene-related peptide (CGRP) are likely mediators of secretory parasympathetic responses of the gland. Previously, we have shown that substance P, VIP and CGRP modulate voltage-dependent Ca(2+) channels (VDCCs) in hamster submandibular ganglion (SMG) neurons. In this study, we attempt to characterize the effect of NPY on VDCCs current using Ba(2+) (I(Ba)) in SMG neurons. Application of NPY caused both facilitation and inhibition of L-type and N/P/Q-type I(Ba), respectively. Intracellular dialysis of the Gα(s)-protein antibody attenuated the NPY-induced facilitation of I(Ba). The adenylate cyclase (AC) inhibitor, as well as protein kinase A (PKA) inhibitor attenuated the NPY-induced facilitation of I(Ba). Intracellular dialysis of the Gα(i)-protein antibody attenuated the NPY-induced inhibition of I(Ba). Application of a strong depolarizing voltage prepulse attenuated the NPY-induced inhibition of I(Ba). These results indicate that NPY facilitates L-type VDCCs via Gα(s)-protein involving AC and PKA. On the other hand, NPY also inhibits N/P/Q-type VDCCs via Gα(i)-protein βγ subunits in the SMG neurons.
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Affiliation(s)
- Takayuki Endoh
- Department of Physiology, Tokyo Dental College, 1-2-2 Masago, Mihama-ku, Chiba 261-8502, Japan.
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37
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Endoh T, Kobayashi H, Nobushima H, Shibukawa Y, Tazaki M, Sueishi K. Prepulse facilitation of calcium channel current in osteoblasts. THE BULLETIN OF TOKYO DENTAL COLLEGE 2012; 53:33-6. [PMID: 22452890 DOI: 10.2209/tdcpublication.53.33] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Osteoblasts play a major role in bone formation. Osteoblasts employ intracellular Ca(2+) as a second messenger modulating hormonal responses and a cofactor for bone mineralization. Voltage-dependent Ca(2+) channels (VDCCs) are most commonly present in excitable cell membranes. They are also present at lower levels even in most nonexcitable cells too. In both types of cell, they mediate the influx of Ca(2+) in response to membrane depolarization. Prepulse facilitation is a phenomenon in which a long and strong depolarizing pulse induces a form of VDCC that exhibits an increased opening probability. We believe this to be the first study to demonstrate that strong depolarization prepulses both increase and decrease VDCCs in osteoblasts.
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Affiliation(s)
- Takayuki Endoh
- Department of Physiology, Tokyo Dental College, Chiba, Japan.
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38
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Abstract
Opioid receptors have been targeted for the treatment of pain and related disorders for thousands of years and remain the most widely used analgesics in the clinic. Mu (μ), kappa (κ), and delta (δ) opioid receptors represent the originally classified receptor subtypes, with opioid receptor like-1 (ORL1) being the least characterized. All four receptors are G-protein coupled and activate inhibitory G proteins. These receptors form homo- and heterodimeric complexes and signal to kinase cascades and scaffold a variety of proteins.The authors discuss classic mechanisms and developments in understanding opioid tolerance and opioid receptor signaling and highlight advances in opioid molecular pharmacology, behavioral pharmacology, and human genetics. The authors put into context how opioid receptor signaling leads to the modulation of behavior with the potential for therapeutic intervention. Finally, the authors conclude there is a continued need for more translational work on opioid receptors in vivo.
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39
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Yu JZ, Rasenick MM. Receptor signaling and the cell biology of synaptic transmission. HANDBOOK OF CLINICAL NEUROLOGY 2012; 106:9-35. [PMID: 22608613 DOI: 10.1016/b978-0-444-52002-9.00002-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
This volume describes a series of psychiatric and neuropsychiatric disorders, connects some aspects of somatic and psychiatric medicine, and describes various current and emerging therapies. The purpose of this chapter is to set the stage for the volume by developing the theoretical basis of synaptic transmission and introducing the various neurotransmitters and their receptors involved in the process. The intent is to provide not only a historical context through which to understand neurotransmitters, but a current contextual basis for understanding neuronal signal transduction and applying this knowledge to facilitate treatment of maladies of the brain and mind.
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Affiliation(s)
- Jiang-Zhou Yu
- Department of Physiology, University of Illinois, Chicago, IL, USA
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40
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Abstract
Voltage-gated ion channels are transmembrane proteins that control nerve impulses and cell homeostasis. Signaling molecules that regulate ion channel activity and density at the plasma membrane must be specifically and efficiently coupled to these channels in order to control critical physiological functions such as action potential propagation. Although their regulation by G-protein receptor activation has been extensively explored, the assembly of ion channels into signaling complexes of GPCRs plays a fundamental role, engaging specific downstream -signaling pathways that trigger precise downstream effectors. Recent work has confirmed that GPCRs can intimately interact with ion channels and serve as -chaperone proteins that finely control their gating and trafficking in subcellular microdomains. This chapter aims to describe examples of GPCR-ion channel co-assembly, focusing mainly on signaling complexes between GPCRs and voltage-gated calcium channels.
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41
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Rebois RV, Hébert TE. Protein Complexes Involved in Heptahelical Receptor-Mediated Signal Transduction. ACTA ACUST UNITED AC 2011. [DOI: 10.3109/10606820308243] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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42
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Compartmentalization of the GABAB receptor signaling complex is required for presynaptic inhibition at hippocampal synapses. J Neurosci 2011; 31:12523-32. [PMID: 21880914 DOI: 10.1523/jneurosci.1527-11.2011] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Presynaptic inhibition via G-protein-coupled receptors (GPCRs) and voltage-gated Ca(2+) channels constitutes a widespread regulatory mechanism of synaptic strength. Yet, the mechanism of intermolecular coupling underlying GPCR-mediated signaling at central synapses remains unresolved. Using FRET spectroscopy, we provide evidence for formation of spatially restricted (<100 Å) complexes between GABA(B) receptors composed of GB(1a)/GB(2) subunits, Gα(o)β(1)γ(2) G-protein heterotrimer, and Ca(V)2.2 channels in hippocampal boutons. GABA release was not required for the assembly but for structural reorganization of the precoupled complex. Unexpectedly, GB(1a) deletion disrupted intermolecular associations within the complex. The GB(1a) proximal C-terminal domain was essential for association of the receptor, Ca(V)2.2 and Gβγ, but was dispensable for agonist-induced receptor activation and cAMP inhibition. Functionally, boutons lacking this complex-formation domain displayed impaired presynaptic inhibition of Ca(2+) transients and synaptic vesicle release. Thus, compartmentalization of the GABA(B1a) receptor, Gβγ, and Ca(V)2.2 channel in a signaling complex is required for presynaptic inhibition at hippocampal synapses.
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43
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Hansen PB, Poulsen CB, Walter S, Marcussen N, Cribbs LL, Skøtt O, Jensen BL. Functional Importance of L- and P/Q-Type Voltage-Gated Calcium Channels in Human Renal Vasculature. Hypertension 2011; 58:464-70. [DOI: 10.1161/hypertensionaha.111.170845] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Calcium channel blockers are widely used for treatment of hypertension, because they decrease peripheral vascular resistance through inhibition of voltage-gated calcium channels. Animal studies of renal vasculature have shown expression of several types of calcium channels that are involved in kidney function. It was hypothesized that human renal vascular excitation-contraction coupling involves different subtypes of channels. In human renal artery and dissected intrarenal blood vessels from nephrectomies, PCR analysis showed expression of L-type (Ca
v
1.2), P/Q-type (Ca
v
2.1), and T-type subtype (Ca
v
3.1 and Ca
v
3.2) voltage-gated calcium channels (Ca
v
s), and quantitative PCR showed highest expression of L-type channels in renal arteries and variable expression between patients of subtypes of calcium channels in intrarenal vessels. Immunohistochemical labeling of kidney sections revealed signals for Ca
v
2.1 and Ca
v
3.1 associated with smooth muscle cells of preglomerular and postglomerular vessels. In human intrarenal arteries, depolarization with potassium induced a contraction inhibited by the L-type antagonist nifedipine, EC
50
1.2×10
−8
mol/L. The T-type antagonist mibefradil inhibited the potassium-induced constriction with large variations between patients. Interestingly, the P/Q-type antagonist, ω-agatoxin IVA, inhibited significantly the contraction with 24% at 10
−9
mol/L. In conclusion L-, P/Q, and T-type channels are expressed in human renal blood vessels, and L- and P/Q-type channels are of functional importance for the depolarization-induced vasoconstriction. The contribution of P/Q-type channels to contraction in the human vasculature is a novel mechanism for the regulation of renal blood flow and suggests that clinical treatment with calcium blockers might affect vascular reactivity also through P/Q-type channel inhibition.
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Affiliation(s)
- Pernille B. Hansen
- From the Cardiovascular and Renal Research (P.B.H., C.B.P., O.S., B.L.J.) and Department of Pathology (N.M.), University of Southern Denmark, Odense, Denmark; Department of Urology (S.W.), Odense University Hospital, Odense, Denmark; Cardiovascular Institute (L.L.C.), Loyola University Medical Center, Maywood, IL
| | - Christian B. Poulsen
- From the Cardiovascular and Renal Research (P.B.H., C.B.P., O.S., B.L.J.) and Department of Pathology (N.M.), University of Southern Denmark, Odense, Denmark; Department of Urology (S.W.), Odense University Hospital, Odense, Denmark; Cardiovascular Institute (L.L.C.), Loyola University Medical Center, Maywood, IL
| | - Steen Walter
- From the Cardiovascular and Renal Research (P.B.H., C.B.P., O.S., B.L.J.) and Department of Pathology (N.M.), University of Southern Denmark, Odense, Denmark; Department of Urology (S.W.), Odense University Hospital, Odense, Denmark; Cardiovascular Institute (L.L.C.), Loyola University Medical Center, Maywood, IL
| | - Niels Marcussen
- From the Cardiovascular and Renal Research (P.B.H., C.B.P., O.S., B.L.J.) and Department of Pathology (N.M.), University of Southern Denmark, Odense, Denmark; Department of Urology (S.W.), Odense University Hospital, Odense, Denmark; Cardiovascular Institute (L.L.C.), Loyola University Medical Center, Maywood, IL
| | - Leanne L. Cribbs
- From the Cardiovascular and Renal Research (P.B.H., C.B.P., O.S., B.L.J.) and Department of Pathology (N.M.), University of Southern Denmark, Odense, Denmark; Department of Urology (S.W.), Odense University Hospital, Odense, Denmark; Cardiovascular Institute (L.L.C.), Loyola University Medical Center, Maywood, IL
| | - Ole Skøtt
- From the Cardiovascular and Renal Research (P.B.H., C.B.P., O.S., B.L.J.) and Department of Pathology (N.M.), University of Southern Denmark, Odense, Denmark; Department of Urology (S.W.), Odense University Hospital, Odense, Denmark; Cardiovascular Institute (L.L.C.), Loyola University Medical Center, Maywood, IL
| | - Boye L. Jensen
- From the Cardiovascular and Renal Research (P.B.H., C.B.P., O.S., B.L.J.) and Department of Pathology (N.M.), University of Southern Denmark, Odense, Denmark; Department of Urology (S.W.), Odense University Hospital, Odense, Denmark; Cardiovascular Institute (L.L.C.), Loyola University Medical Center, Maywood, IL
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44
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Evolving therapeutic indications for N-type calcium channel blockers: from chronic pain to alcohol abuse. Future Med Chem 2011; 2:791-802. [PMID: 21426203 DOI: 10.4155/fmc.10.30] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Clinical exploitation of the therapeutic potential of calcium channels has long been limited to L-type blockers for cardiovascular diseases. Recently, N-type blockers have been fully validated for the treatment of chronic pain, following approval of the intrathecally active ziconotide (Prialt(®)). This review describes the successful efforts to broaden the therapeutic scope of this mechanism to other major CNS indications, based on the discovery of N-type blockers orally active against pain. In animal models, the N-type blocker and pain-reducing NP078585 is efficacious against key elements of ethanol dependency, including self-administration and relapse. NP078585 moderately stimulates brain dopamine release without inducing reward or hyperlocomotion. N-type blockers may emerge as a novel class of 'dopamine stabilizers' for the treatment of drug dependency and other neuropsychiatric disorders without the side effects of current therapies.
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45
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Bray JG, Mynlieff M. Involvement of protein kinase C and protein kinase A in the enhancement of L-type calcium current by GABAB receptor activation in neonatal hippocampus. Neuroscience 2011; 179:62-72. [PMID: 21277353 DOI: 10.1016/j.neuroscience.2011.01.054] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Accepted: 01/23/2011] [Indexed: 10/18/2022]
Abstract
In the early neonatal period activation of GABAB receptors attenuates calcium current through N-type calcium channels while enhancing current through L-type calcium channels in rat hippocampal neurons. The attenuation of N-type calcium current has been previously demonstrated to occur through direct interactions of the βγ subunits of Gi/o G-proteins, but the signal transduction pathway for the enhancement of L-type calcium channels in mammalian neurons remains unknown. In the present study, calcium currents were elicited in acute cultures from postnatal day 6-8 rat hippocampi in the presence of various modulators of protein kinase A (PKA) and protein kinase C (PKC) pathways. Overnight treatment with an inhibitor of Gi/o (pertussis toxin, 200 ng/ml) abolished the attenuation of calcium current by the GABAB agonist, baclofen (10 μM) with no effect on the enhancement of calcium current. These data indicate that while the attenuation of N-type calcium current is mediated by the Gi/o subtype of G-protein, the enhancement of L-type calcium current requires activation of a different G-protein. The enhancement of the sustained component of calcium current by baclofen was blocked by PKC inhibitors, GF-109203X (500 nM), chelerythrine chloride (5 μM), and PKC fragment 19-36 (2 μM) and mimicked by the PKC activator phorbol-12-myristate-13-acetate (1 μM). The enhancement of the sustained component of calcium current was blocked by PKA inhibitors H-89 (1 μM) and PKA fragment 6-22 (500 nM) but not Rp-cAMPS (30 μM) and it was not mimicked by the PKA activator, 8-Br-cAMP (500 μM-1 mM). The data suggest that activation of PKC alone is sufficient to enhance L-type calcium current but that PKA may also be involved in the GABAB receptor mediated effect.
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Affiliation(s)
- J G Bray
- Department of Biological Sciences, Marquette University, P.O. Box 1881, Milwaukee, WI 53201-1881, USA
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46
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Abstract
Manganese-enhanced magnetic resonance imaging (MEMRI) relies on contrasts that are due to the shortening of the T (1) relaxation time of tissue water protons that become exposed to paramagnetic manganese ions. In experimental animals, the technique combines the high spatial resolution achievable by MRI with the biological information gathered by tissue-specific or functionally induced accumulations of manganese. After in vivo administration, manganese ions may enter cells via voltage-gated calcium channels. In the nervous system, manganese ions are actively transported along the axon. Based on these properties, MEMRI is increasingly used to delineate neuroanatomical structures, assess differences in functional brain activity, and unravel neuronal connectivities in both healthy animals and models of neurological disorders. Because of the cellular toxicity of manganese, a major challenge for a successful MEMRI study is to achieve the lowest possible dose for a particular biological question. Moreover, the interpretation of MEMRI findings requires a profound knowledge of the behavior of manganese in complex organ systems under physiological and pathological conditions. Starting with an overview of manganese pharmacokinetics and mechanisms of toxicity, this chapter covers experimental methods and protocols for applications in neuroscience.
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Affiliation(s)
- Susann Boretius
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, 37077 Göttingen, Germany.
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47
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Abstract
Voltage-gated Ca(2+) channels translate the electrical inputs of excitable cells into biochemical outputs by controlling influx of the ubiquitous second messenger Ca(2+) . As such the channels play pivotal roles in many cellular functions including the triggering of neurotransmitter and hormone release by CaV2.1 (P/Q-type) and CaV2.2 (N-type) channels. It is well established that G protein coupled receptors (GPCRs) orchestrate precise regulation neurotransmitter and hormone release through inhibition of CaV2 channels. Although the GPCRs recruit a number of different pathways, perhaps the most prominent, and certainly most studied among these is the so-called voltage-dependent inhibition mediated by direct binding of Gβγ to the α1 subunit of CaV2 channels. This article will review the basics of Ca(2+) -channels and G protein signaling, and the functional impact of this now classical inhibitory mechanism on channel function. It will also provide an update on more recent developments in the field, both related to functional effects and crosstalk with other signaling pathways, and advances made toward understanding the molecular interactions that underlie binding of Gβγ to the channel and the voltage-dependence that is a signature characteristic of this mechanism.
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Affiliation(s)
- Kevin P M Currie
- Department of Anesthesiology, Pharmacology and Center for Molecular Neuroscience, Vanderbilt University School of Medicine, Nashville, TN, USA.
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48
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Won YJ, Ono F, Ikeda SR. Identification and modulation of voltage-gated Ca2+ currents in zebrafish Rohon-Beard neurons. J Neurophysiol 2010; 105:442-53. [PMID: 20962070 DOI: 10.1152/jn.00625.2010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Electrically excitable cells have voltage-dependent ion channels on the plasma membrane that regulate membrane permeability to specific ions. Voltage-gated Ca(2+) channels (VGCCs) are especially important as Ca(2+) serves as both a charge carrier and second messenger. Zebrafish (Danio rerio) are an important model vertebrate for studies of neuronal excitability, circuits, and behavior. However, electrophysiological properties of zebrafish VGCCs remain largely unexplored because a suitable preparation for whole cell voltage-clamp studies is lacking. Rohon-Beard (R-B) sensory neurons represent an attractive candidate for this purpose because of their relatively large somata and functional homology to mammalian dorsal root ganglia (DRG) neurons. Transgenic zebrafish expressing green fluorescent protein in R-B neurons, (Isl2b:EGFP)(ZC7), were used to identify dissociated neurons suitable for whole cell patch-clamp experiments. Based on biophysical and pharmacological properties, zebrafish R-B neurons express both high- and low-voltage-gated Ca(2+) current (HVA- and LVA-I(Ca), respectively). Ni(+)-sensitive LVA-I(Ca) occur in the minority of R-B neurons (30%) and ω-conotoxin GVIA-sensitive Ca(V)2.2 (N-type) Ca(2+) channels underlie the vast majority (90%) of HVA-I(Ca). To identify G protein coupled receptors (GPCRs) that modulate HVA-I(Ca), a panel of neurotransmitters was screened. Application of GABA/baclofen or serotonin produced a voltage-dependent inhibition while application of the mu-opioid agonist DAMGO resulted in a voltage-independent inhibition. Unlike in mammalian neurons, GPCR-mediated voltage-dependent modulation of I(Ca) appears to be transduced primarily via a cholera toxin-sensitive Gα subunit. These results provide the basis for using the zebrafish model system to understanding Ca(2+) channel function, and in turn, how Ca(2+) channels contribute to mechanosensory function.
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Affiliation(s)
- Yu-Jin Won
- 1Section on Transmitter Signaling, Laboratory of Molecular Physiology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland 20892-9411, USA
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49
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Tselnicker I, Tsemakhovich VA, Dessauer CW, Dascal N. Stargazin modulates neuronal voltage-dependent Ca(2+) channel Ca(v)2.2 by a Gbetagamma-dependent mechanism. J Biol Chem 2010; 285:20462-71. [PMID: 20435886 DOI: 10.1074/jbc.m110.121277] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Loss of neuronal protein stargazin (gamma(2)) is associated with recurrent epileptic seizures and ataxia in mice. Initially, due to homology to the skeletal muscle calcium channel gamma(1) subunit, stargazin and other family members (gamma(3-8)) were classified as gamma subunits of neuronal voltage-gated calcium channels (such as Ca(V)2.1-Ca(V)2.3). Here, we report that stargazin interferes with G protein modulation of Ca(V)2.2 (N-type) channels expressed in Xenopus oocytes. Stargazin counteracted the Gbetagamma-induced inhibition of Ca(V)2.2 channel currents, caused either by coexpression of the Gbetagamma dimer or by activation of a G protein-coupled receptor. Expression of high doses of Gbetagamma overcame the effects of stargazin. High affinity Gbetagamma scavenger proteins m-cbetaARK and m-phosducin produced effects similar to stargazin. The effects of stargazin and m-cbetaARK were not additive, suggesting a common mechanism of action, and generally independent of the presence of the Ca(V)beta(3) subunit. However, in some cases, coexpression of Ca(V)beta(3) blunted the modulation by stargazin. Finally, the Gbetagamma-opposing action of stargazin was not unique to Ca(V)2.2, as stargazin also inhibited the Gbetagamma-mediated activation of the G protein-activated K(+) channel. Purified cytosolic C-terminal part of stargazin bound Gbetagamma in vitro. Our results suggest that the regulation by stargazin of biophysical properties of Ca(V)2.2 are not exerted by direct modulation of the channel but via a Gbetagamma-dependent mechanism.
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Affiliation(s)
- Isabella Tselnicker
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
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50
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Tedford HW, Kisilevsky AE, Vieira LB, Varela D, Chen L, Zamponi GW. Scanning mutagenesis of the I-II loop of the Cav2.2 calcium channel identifies residues Arginine 376 and Valine 416 as molecular determinants of voltage dependent G protein inhibition. Mol Brain 2010; 3:6. [PMID: 20181083 PMCID: PMC2829547 DOI: 10.1186/1756-6606-3-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Accepted: 02/03/2010] [Indexed: 11/01/2022] Open
Abstract
Direct interaction with the beta subunit of the heterotrimeric G protein complex causes voltage-dependent inhibition of N-type calcium channels. To further characterize the molecular determinants of this interaction, we performed scanning mutagenesis of residues 372-387 and 410-428 of the N-type channel alpha1 subunit, in which individual residues were replaced by either alanine or cysteine. We coexpressed wild type Gbeta1gamma2 subunits with either wild type or point mutant N-type calcium channels, and voltage-dependent, G protein-mediated inhibition of the channels (VDI) was assessed using patch clamp recordings. The resulting data indicate that Arg376 and Val416 of the alpha1 subunit, residues which are surface-exposed in the presence of the calcium channel beta subunit, contribute significantly to the functional inhibition by Gbeta1. To further characterize the roles of Arg376 and Val416 in this interaction, we performed secondary mutagenesis of these residues, coexpressing the resulting mutants with wild type Gbeta1gamma2 subunits and with several isoforms of the auxiliary beta subunit of the N-type channel, again assessing VDI using patch clamp recordings. The results confirm the importance of Arg376 for G protein-mediated inhibition and show that a single amino acid substitution to phenylalanine drastically alters the abilities of auxiliary calcium channel subunits to regulate G protein inhibition of the channel.
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Affiliation(s)
- Hugo W Tedford
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, University of Calgary, Canada
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