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Sharma V, Sharma P, Singh TG. Therapeutic potential of transient receptor potential (TRP) channels in psychiatric disorders. J Neural Transm (Vienna) 2024; 131:1025-1037. [PMID: 39007920 DOI: 10.1007/s00702-024-02803-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Accepted: 06/28/2024] [Indexed: 07/16/2024]
Abstract
Psychiatric disorders such as Bipolar disorder, Anxiety, Major depressive disorder, Schizophrenia, Attention-deficit/hyperactivity disorder, as well as neurological disorders such as Migraine, are linked by the evidence of altered calcium homeostasis. The disturbance of intra-cellular calcium homeostasis disrupts the activity of numerous ion channels including transient receptor potential (TRP) channels. TRP channel families comprise non-selective calcium-permeable channels that have been implicated in variety of physiological processes in the brain, as well as in the pathogenesis of psychiatric disorders. Through a comprehensive review of current research and experimentation, this investigation elucidates the role of TRP channels in psychiatric disorders. Furthermore, this review discusses about the exploration of epigenetics and TRP channels in psychiatric disorders.
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Affiliation(s)
- Veerta Sharma
- Chitkara College of Pharmacy, Chitkara University, Rajpura, 140401, Punjab, India
| | - Prateek Sharma
- Chitkara College of Pharmacy, Chitkara University, Rajpura, 140401, Punjab, India
| | - Thakur Gurjeet Singh
- Chitkara College of Pharmacy, Chitkara University, Rajpura, 140401, Punjab, India.
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2
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Llanos MA, Enrique N, Esteban-López V, Scioli-Montoto S, Sánchez-Benito D, Ruiz ME, Milesi V, López DE, Talevi A, Martín P, Gavernet L. A Combined Ligand- and Structure-Based Virtual Screening To Identify Novel NaV1.2 Blockers: In Vitro Patch Clamp Validation and In Vivo Anticonvulsant Activity. J Chem Inf Model 2023; 63:7083-7096. [PMID: 37917937 DOI: 10.1021/acs.jcim.3c00645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2023]
Abstract
Epilepsy is a neurological disorder characterized by recurrent seizures that arise from abnormal electrical activity in the brain. Voltage-gated sodium channels (NaVs), responsible for the initiation and propagation of action potentials in neurons, play a critical role in the pathogenesis of epilepsy. This study sought to discover potential anticonvulsant compounds that interact with NaVs, specifically, the brain subtype hNaV1.2. A ligand-based QSAR model and a docking model were constructed, validated, and applied in a parallel virtual screening over the DrugBank database. Montelukast, Novobiocin, and Cinnarizine were selected for in vitro testing, using the patch-clamp technique, and all of them proved to inhibit hNaV1.2 channels heterologously expressed in HEK293 cells. Two hits were evaluated in the GASH/Sal model of audiogenic seizures and demonstrated promising activity, reducing the severity of sound-induced seizures at the doses tested. The combination of ligand- and structure-based models presents a valuable approach for identifying potential NaV inhibitors. These findings may provide a basis for further research into the development of new antiseizure drugs for the treatment of epilepsy.
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Affiliation(s)
- Manuel A Llanos
- Laboratory of Bioactive Compounds Research and Development (LIDeB), Department of Biological Sciences, Faculty of Exact Sciences, National University of La Plata (UNLP), La Plata B1900ADU, Argentina
| | - Nicolás Enrique
- Facultad de Ciencias Exactas, Departamento de Ciencias Biológicas, Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), UNLP, CONICET, asociado CIC PBA, La Plata B1900BJW, Buenos Aires, Argentina
| | - Vega Esteban-López
- Institute for Neuroscience of Castilla y León (INCyL), University of Salamanca, Salamanca 37008, Spain
- Institute for Biomedical Research of Salamanca (IBSAL), Salamanca 37007, Spain
| | - Sebastian Scioli-Montoto
- Laboratory of Bioactive Compounds Research and Development (LIDeB), Department of Biological Sciences, Faculty of Exact Sciences, National University of La Plata (UNLP), La Plata B1900ADU, Argentina
| | - David Sánchez-Benito
- Institute for Neuroscience of Castilla y León (INCyL), University of Salamanca, Salamanca 37008, Spain
- Institute for Biomedical Research of Salamanca (IBSAL), Salamanca 37007, Spain
| | - María E Ruiz
- Laboratory of Bioactive Compounds Research and Development (LIDeB), Department of Biological Sciences, Faculty of Exact Sciences, National University of La Plata (UNLP), La Plata B1900ADU, Argentina
| | - Veronica Milesi
- Facultad de Ciencias Exactas, Departamento de Ciencias Biológicas, Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), UNLP, CONICET, asociado CIC PBA, La Plata B1900BJW, Buenos Aires, Argentina
| | - Dolores E López
- Institute for Neuroscience of Castilla y León (INCyL), University of Salamanca, Salamanca 37008, Spain
- Institute for Biomedical Research of Salamanca (IBSAL), Salamanca 37007, Spain
| | - Alan Talevi
- Laboratory of Bioactive Compounds Research and Development (LIDeB), Department of Biological Sciences, Faculty of Exact Sciences, National University of La Plata (UNLP), La Plata B1900ADU, Argentina
| | - Pedro Martín
- Facultad de Ciencias Exactas, Departamento de Ciencias Biológicas, Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), UNLP, CONICET, asociado CIC PBA, La Plata B1900BJW, Buenos Aires, Argentina
| | - Luciana Gavernet
- Laboratory of Bioactive Compounds Research and Development (LIDeB), Department of Biological Sciences, Faculty of Exact Sciences, National University of La Plata (UNLP), La Plata B1900ADU, Argentina
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Wang M, Gu Y, Meng S, Kang L, Yang J, Sun D, Liu Y, Wan Z, Shan Y, Xue D, Su C, Li S, Yan R, Liu Y, Zhao Y, Pan Y. Association between TRP channels and glutamatergic synapse gene polymorphisms and migraine and the comorbidities anxiety and depression in a Chinese population. Front Genet 2023; 14:1158028. [PMID: 37303955 PMCID: PMC10250607 DOI: 10.3389/fgene.2023.1158028] [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: 02/03/2023] [Accepted: 05/17/2023] [Indexed: 06/13/2023] Open
Abstract
Background: Genetic and environmental factors contribute to migraine and the comorbidities of anxiety and depression. However, the association between genetic polymorphisms in the transient receptor potential (TRP) channels and glutamatergic synapse genes with the risk of migraine and the comorbidities of anxiety and depression remain unclear. Methods: 251 migraine patients containing 49 comorbidities with anxiety and 112 with depression and 600 controls were recruited. A customized 48-plex SNPscan kit was used for genotyping 13 SNPs of nine target genes. Logistic regression was conducted to analyze these SNPs' association with the susceptibility of migraine and comorbidities. The generalized multifactor dimension reduction (GMDR) was applied to analyze the SNP-SNP and gene-environment interactions. The GTEx database was used to examine the effects of the significant SNPs on gene expressions. Results: The TRPV1 rs8065080 and TRPV3 rs7217270 were associated with an increased risk of migraine in the dominant model [ORadj (95% CI): 1.75 (1.09-2.90), p = 0.025; 1.63 (1.02-2.58), p = 0.039, respectively]. GRIK2 rs2227283 was associated with migraine in the edge of significance [ORadj (95% CI) = 1.36 (0.99-1.89), p = 0.062]. In migraine patients, TRPV1 rs222741 was associated with both anxiety risk and depression risk in the recessive model [ORadj (95% CI): 2.64 (1.24-5.73), p = 0.012; 1.97 (1.02-3.85), p = 0.046, respectively]. TRPM8 rs7577262 was associated with anxiety (ORadj = 0.27, 95% CI = 0.10-0.76, p = 0.011). TRPV4 rs3742037, TRPM8 rs17862920 and SLC17A8 rs11110359 were associated with depression in dominant model [ORadj (95% CI): 2.03 (1.06-3.96), p = 0.035; 0.48 (0.23-0.96), p = 0.042; 0.42 (0.20-0.84), p = 0.016, respectively]. Significant eQTL and sQTL signals were observed for SNP rs8065080. Individuals with GRS (Genetic risk scores) of Q4 (14-17) had a higher risk of migraine and a lower risk of comorbidity anxiety than those with Genetic risk scores scores of Q1 (0-9) groups [ORadj (95% CI): 2.31 (1.39-3.86), p = 0.001; 0.28 (0.08-0.88), p = 0.034, respectively]. Conclusion: This study suggests that TRPV1 rs8065080, TRPV3 rs7217270, and GRIK2 rs2227283 polymorphism may associate with migraine risk. TRPV1 rs222741 and TRPM8 rs7577262 may associate with migraine comorbidity anxiety risk. rs222741, rs3742037, rs17862920, and rs11110359 may associate with migraine comorbidity depression risk. Higher GRS scores may increase migraine risk and decrease comorbidity anxiety risk.
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Affiliation(s)
- Mingxue Wang
- Department of Epidemiology, School of Public Health, Harbin Medical University, Harbin, China
| | - Yujia Gu
- Chronic Disease Prevention and Treatment Clinic, Heilongjiang Provincial Center for Disease Control and Prevention, Harbin, China
| | - Shuhan Meng
- Department of Epidemiology, School of Public Health, Harbin Medical University, Harbin, China
| | - Lixin Kang
- Department of Epidemiology, School of Public Health, Harbin Medical University, Harbin, China
| | - Jing Yang
- Department of Neurology, Beidahuang Group Hongxinglong Hospital, Shuangyashan, China
| | - Degang Sun
- Department of Neurology, Beidahuang Group Hongxinglong Hospital, Shuangyashan, China
| | - Yuxing Liu
- Catheterization Room, Beidahuang Group Hongxinglong Hospital, Shuangyashan, China
| | - Ze Wan
- Science and Education Section, Beidahuang Group Hongxinglong Hospital, Shuangyashan, China
| | - Yi Shan
- Physical Examination Section, Beidahuang Group Baoquanling Hospital, Hegang, China
| | - Dongjie Xue
- Department of Neurology, Hegang He Mine Hospital, Hegang, China
| | - Chang Su
- Department of Internal Medicine, Baoquanling Farm Hospital, Hegang, China
| | - Shufen Li
- Vaccination Clinic, Baoquanling Farm Hospital, Hegang, China
| | - Ran Yan
- Department of Epidemiology, School of Public Health, Harbin Medical University, Harbin, China
| | - Yu Liu
- Chronic Disease Prevention and Treatment Clinic, Heilongjiang Provincial Center for Disease Control and Prevention, Harbin, China
| | - Yashuang Zhao
- Department of Epidemiology, School of Public Health, Harbin Medical University, Harbin, China
| | - Yonghui Pan
- Department of Neurology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
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Llanos MA, Enrique N, Sbaraglini ML, Garofalo FM, Talevi A, Gavernet L, Martín P. Structure-Based Virtual Screening Identifies Novobiocin, Montelukast, and Cinnarizine as TRPV1 Modulators with Anticonvulsant Activity In Vivo. J Chem Inf Model 2022; 62:3008-3022. [PMID: 35696534 DOI: 10.1021/acs.jcim.2c00312] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The transient receptor potential vanilloid 1 (TRPV1) receptor is a nonselective cation channel, known to be involved in the regulation of many important physiological and pathological processes. In the last few years, it has been proposed as a promising target to develop novel anticonvulsant compounds. However, thermoregulatory effects associated with the channel inhibition have hampered the path for TRPV1 antagonists to become marketed drugs. In this regard, we conducted a structure-based virtual screening campaign to find potential TRPV1 modulators among approved drugs, which are known to be safe and thermally neutral. To this end, different docking models were developed and validated by assessing their pose and score prediction powers. Novobiocin, montelukast, and cinnarizine were selected from the screening as promising candidates for experimental testing and all of them exhibited nanomolar inhibitory activity. Moreover, the in vivo profiles showed promising results in at least one of the three models of seizures tested.
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Affiliation(s)
- Manuel A Llanos
- Departamento de Ciencias Biológicas and Laboratorio de Investigación y Desarrollo de Bioactivos (LIDeB), UNLP, Facultad de Ciencias Exactas, La Plata Buenos Aires (B1900ADU), Argentina
| | - Nicolás Enrique
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP, CONICET─Universidad Nacional de la Plata), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata Buenos Aires (B1900BJW), Argentina
| | - María L Sbaraglini
- Departamento de Ciencias Biológicas and Laboratorio de Investigación y Desarrollo de Bioactivos (LIDeB), UNLP, Facultad de Ciencias Exactas, La Plata Buenos Aires (B1900ADU), Argentina
| | - Federico M Garofalo
- Departamento de Ciencias Biológicas and Laboratorio de Investigación y Desarrollo de Bioactivos (LIDeB), UNLP, Facultad de Ciencias Exactas, La Plata Buenos Aires (B1900ADU), Argentina
| | - Alan Talevi
- Departamento de Ciencias Biológicas and Laboratorio de Investigación y Desarrollo de Bioactivos (LIDeB), UNLP, Facultad de Ciencias Exactas, La Plata Buenos Aires (B1900ADU), Argentina
| | - Luciana Gavernet
- Departamento de Ciencias Biológicas and Laboratorio de Investigación y Desarrollo de Bioactivos (LIDeB), UNLP, Facultad de Ciencias Exactas, La Plata Buenos Aires (B1900ADU), Argentina
| | - Pedro Martín
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP, CONICET─Universidad Nacional de la Plata), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata Buenos Aires (B1900BJW), Argentina
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5
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Jamieson BB, Kim JS, Iremonger KJ. Cannabinoid and vanilloid pathways mediate opposing forms of synaptic plasticity in corticotropin-releasing hormone neurons. J Neuroendocrinol 2022; 34:e13084. [PMID: 35034400 DOI: 10.1111/jne.13084] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 12/20/2021] [Accepted: 12/23/2021] [Indexed: 01/18/2023]
Abstract
Activity-dependent release of retrograde signaling molecules form micro-feedback loops to regulate synaptic function in neural circuits. Single neurons can release multiple forms of these signaling molecules, including endocannabinoids and endovanilloids, which act via cannabinoid (CB) receptors and transient receptor potential vanilloid 1 (TRPV1) receptors. In hypothalamic corticotrophin-releasing hormone (CRH) neurons, endocannabinoids acting via CB1 receptors have been shown to play an important role in regulating excitability and hence stress hormone secretion. However, the importance of endovanilloid signaling in CRH neurons is currently unclear. Here, we show that, in response to postsynaptic depolarization, CRH neurons release endocannabinoid/endovanilloid molecules that can activate CB1 and TRPV1 receptors. Activation of CB1 receptors suppresses glutamate neurotransmission whereas activation of TRPV1 enhances spontaneous glutamate transmission. However, the excitatory effects of TRPV1 are normally masked by the inhibitory effects of CB1. When the degradation of the endocannabinoid 2-arachidonoylglycerol (2-AG) was inhibited, this revealed tonic activation of CB1 receptors, suggesting tonic endocannabinoid release. However, we found no evidence for tonic activation of TRPV1 receptors under similar conditions. These findings show that activation of CRH neurons can drive the release of signaling molecules that activate parallel endocannabinoid and endovanilloid receptor pathways to mediate opposing forms of synaptic plasticity.
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Affiliation(s)
- Bradley B Jamieson
- Centre for Neuroendocrinology, Department of Physiology, University of Otago, Dunedin, New Zealand
| | - Joon S Kim
- Centre for Neuroendocrinology, Department of Physiology, University of Otago, Dunedin, New Zealand
| | - Karl J Iremonger
- Centre for Neuroendocrinology, Department of Physiology, University of Otago, Dunedin, New Zealand
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6
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Wang X, Liao Q, Chen H, Gong G, Siu SWI, Chen Q, Kam H, Ung COL, Cheung KK, Rádis-Baptista G, Wong CTT, Lee SMY. Toxic Peptide From Palythoa caribaeorum Acting on the TRPV1 Channel Prevents Pentylenetetrazol-Induced Epilepsy in Zebrafish Larvae. Front Pharmacol 2021; 12:763089. [PMID: 34925021 PMCID: PMC8672801 DOI: 10.3389/fphar.2021.763089] [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: 08/23/2021] [Accepted: 11/08/2021] [Indexed: 11/25/2022] Open
Abstract
PcActx peptide, identified from the transcriptome of zoantharian Palythoa caribaeorum, was clustered into the phylogeny of analgesic polypeptides from sea anemone Heteractis crispa (known as APHC peptides). APHC peptides were considered as inhibitors of transient receptor potential cation channel subfamily V member 1 (TRPV1). TRPV1 is a calcium-permeable channel expressed in epileptic brain areas, serving as a potential target for preventing epileptic seizures. Through in silico and in vitro analysis, PcActx peptide was shown to be a potential TRPV1 channel blocker. In vivo studies showed that the linear and oxidized PcActx peptides caused concentration-dependent increases in mortality of zebrafish larvae. However, monotreatment with PcActx peptides below the maximum tolerated doses (MTD) did not affect locomotor behavior. Moreover, PcActx peptides (both linear and oxidized forms) could effectively reverse pentylenetetrazol (PTZ)-induced seizure-related behavior in zebrafish larvae and prevent overexpression of c-fos and npas4a at the mRNA level. The excessive production of ROS induced by PTZ was markedly attenuated by both linear and oxidized PcActx peptides. It was also verified that the oxidized PcActx peptide was more effective than the linear one. In particular, oxidized PcActx peptide notably modulated the mRNA expression of genes involved in calcium signaling and γ-aminobutyric acid (GABA)ergic-glutamatergic signaling, including calb1, calb2, gabra1, grm1, gria1b, grin2b, gat1, slc1a2b, gad1b, and glsa. Taken together, PcActx peptide, as a novel neuroactive peptide, exhibits prominent anti-epileptic activity, probably through modulating calcium signaling and GABAergic-glutamatergic signaling, and is a promising candidate for epilepsy management.
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Affiliation(s)
- Xiufen Wang
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macau, China
| | - Qiwen Liao
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macau, China.,School of Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen, China
| | - Hanbin Chen
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macau, China
| | - Guiyi Gong
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macau, China
| | - Shirley Weng In Siu
- Department of Computer and Information Science, Faculty of Science and Technology, University of Macau, Macau, China
| | - Qian Chen
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macau, China
| | - Hiotong Kam
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macau, China
| | - Carolina Oi Lam Ung
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macau, China
| | - Kwok-Kuen Cheung
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong, China
| | - Gandhi Rádis-Baptista
- Laboratory of Biochemistry and Biotechnology, Institute for Marine Sciences, Federal University of Ceará, Fortaleza, Brazil
| | - Clarence Tsun Ting Wong
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China
| | - Simon Ming-Yuen Lee
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macau, China
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Fawley JA, Hegarty DM, Aicher SA, Beaumont E, Andresen MC. Dedicated C-fiber vagal sensory afferent pathways to the paraventricular nucleus of the hypothalamus. Brain Res 2021; 1769:147625. [PMID: 34416255 PMCID: PMC8438991 DOI: 10.1016/j.brainres.2021.147625] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/24/2021] [Accepted: 08/12/2021] [Indexed: 12/22/2022]
Abstract
The nucleus of the solitary tract (NTS) receives viscerosensory information from the vagus nerve to regulate diverse homeostatic reflex functions. The NTS projects to a wide network of other brain regions, including the paraventricular nucleus of the hypothalamus (PVN). Here we examined the synaptic characteristics of primary afferent pathways to PVN-projecting NTS neurons in rat brainstem slices.Expression of the Transient Receptor Potential Vanilloid receptor (TRPV1+ ) distinguishes C-fiber afferents within the solitary tract (ST) from A-fibers (TRPV1-). We used resiniferatoxin (RTX), a TRPV1 agonist, to differentiate the two. The variability in the latency (jitter) of evoked excitatory postsynaptic currents (ST-EPSCs) distinguished monosynaptic from polysynaptic ST-EPSCs. Rhodamine injected into PVN was retrogradely transported to identify PVN-projecting NTS neurons within brainstem slices. Graded shocks to the ST elicited all-or-none EPSCs in rhodamine-positive NTS neurons with latencies that had either low jitter (<200 µs - monosynaptic), high jitter (>200 µs - polysynaptic inputs) or both. RTX blocked ST-evoked TRPV1 + EPSCs whether mono- or polysynaptic. Most PVN-projecting NTS neurons (17/21 neurons) had at least one input polysynaptically connected to the ST. Compared to unlabeled NTS neurons, PVN-projecting NTS neurons were more likely to receive indirect inputs and be higher order. Surprisingly, sEPSC rates for PVN-projecting neurons were double that of unlabeled NTS neurons. The ST synaptic responses for PVN-projecting NTS neurons were either all TRPV1+ or all TRPV1-, including neurons that received both direct and indirect inputs. Overall, PVN-projecting NTS neurons received direct and indirect vagal afferent information with strict segregation regarding TRPV1 expression.
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Affiliation(s)
- Jessica A Fawley
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, OR 97239, United States
| | - Deborah M Hegarty
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, OR 97239, United States
| | - Sue A Aicher
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, OR 97239, United States
| | - Eric Beaumont
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, United States
| | - Michael C Andresen
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, OR 97239, United States.
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8
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Li WR, Wang YL, Li C, Gao P, Zhang FF, Hu M, Li JC, Zhang S, Li R, Zhang CX. Synaptotagmin-11 inhibits spontaneous neurotransmission through vti1a. J Neurochem 2021; 159:729-741. [PMID: 34599505 DOI: 10.1111/jnc.15523] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 11/25/2020] [Accepted: 09/26/2021] [Indexed: 12/25/2022]
Abstract
Recent work has revealed that spontaneous release plays critical roles in the central nervous system, but how it is regulated remains elusive. Here, we report that synaptotagmin-11 (Syt11), a Ca2+ -independent Syt isoform associated with schizophrenia and Parkinson's disease, suppressed spontaneous release. Syt11-knockout hippocampal neurons showed an increased frequency of miniature excitatory post-synaptic currents while over-expression of Syt11 inversely decreased the frequency. Neither knockout nor over-expression of Syt11 affected the average amplitude, suggesting the pre-synaptic regulation of spontaneous neurotransmission by Syt11. Glutathione S-transferase pull-down, co-immunoprecipitation, and affinity-purification experiments demonstrated a direct interaction of Syt11 with vps10p-tail-interactor-1a (vti1a), a non-canonical SNARE protein that maintains spontaneous release. Importantly, knockdown of vti1a reversed the phenotype of Syt11 knockout, identifying vti1a as the main target of Syt11 inhibition. Domain analysis revealed that the C2A domain of Syt11 bound vti1a with high affinity. Consistently, expression of the C2A domain alone rescued the phenotype of elevated spontaneous release in Syt11-knockout neurons similar to the full-length protein. Altogether, our results suggest that Syt11 inhibits vti1a-containing vesicles during spontaneous release.
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Affiliation(s)
- Wan-Ru Li
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Ya-Long Wang
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Chao Li
- State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Pei Gao
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Fei-Fan Zhang
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Meiqin Hu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Jing-Chen Li
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Shuli Zhang
- State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Rena Li
- Beijing Key Laboratory of Mental Disorders, Beijing Anding Hospital and Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
| | - Claire Xi Zhang
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China.,Academy of Pharmacy, Xi'an Jiaotong-Liverpool University, Suzhou, China
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9
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Ragozzino FJ, Arnold RA, Fenwick AJ, Riley TP, Lindberg JEM, Peterson B, Peters JH. TRPM3 expression and control of glutamate release from primary vagal afferent neurons. J Neurophysiol 2020; 125:199-210. [PMID: 33296617 DOI: 10.1152/jn.00229.2020] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Vagal afferent fibers contact neurons in the nucleus of the solitary tract (NTS) and release glutamate via three distinct release pathways: synchronous, asynchronous, and spontaneous. The presence of TRPV1 in vagal afferents is predictive of activity-dependent asynchronous glutamate release along with temperature-sensitive spontaneous vesicle fusion. However, pharmacological blockade or genetic deletion of TRPV1 does not eliminate the asynchronous profile and only attenuates the temperature-dependent spontaneous release at high temperatures (>40°C), indicating additional temperature-sensitive calcium conductance(s) contributing to these release pathways. The transient receptor potential cation channel melastatin subtype 3 (TRPM3) is a calcium-selective channel that functions as a thermosensor (30-37°C) in somatic primary afferent neurons. We predict that TRPM3 is expressed in vagal afferent neurons and contributes to asynchronous and spontaneous glutamate release pathways. We investigated these hypotheses via measurements on cultured nodose neurons and in brainstem slice preparations containing vagal afferent to NTS synaptic contacts. We found histological and genetic evidence that TRPM3 is highly expressed in vagal afferent neurons. The TRPM3-selective agonist, pregnenolone sulfate, rapidly and reversibly activated the majority (∼70%) of nodose neurons; most of which also contained TRPV1. We confirmed the role of TRPM3 with pharmacological blockade and genetic deletion. In the brain, TRPM3 signaling strongly controlled both basal and temperature-driven spontaneous glutamate release. Surprisingly, genetic deletion of TRPM3 did not alter synchronous or asynchronous glutamate release. These results provide convergent evidence that vagal afferents express functional TRPM3 that serves as an additional temperature-sensitive calcium conductance involved in controlling spontaneous glutamate release onto neurons in the NTS.NEW & NOTEWORTHY Vagal afferent signaling coordinates autonomic reflex function and informs associated behaviors. Thermosensitive transient receptor potential (TRP) channels detect temperature and nociceptive stimuli in somatosensory afferent neurons, however their role in vagal signaling remains less well understood. We report that the TRPM3 ion channel provides a major thermosensitive point of control over vagal signaling and synaptic transmission. We conclude that TRPM3 translates physiological changes in temperature to neurophysiological outputs and can serve as a cellular integrator in vagal afferent signaling.
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Affiliation(s)
- Forrest J Ragozzino
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
| | - Rachel A Arnold
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
| | - Axel J Fenwick
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
| | - Timothy P Riley
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
| | - Jonathan E M Lindberg
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
| | - BreeAnne Peterson
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
| | - James H Peters
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
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10
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Ragozzino FJ, Arnold RA, Kowalski CW, Savenkova MI, Karatsoreos IN, Peters JH. Corticosterone inhibits vagal afferent glutamate release in the nucleus of the solitary tract via retrograde endocannabinoid signaling. Am J Physiol Cell Physiol 2020; 319:C1097-C1106. [PMID: 32966126 DOI: 10.1152/ajpcell.00190.2020] [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] [Indexed: 11/22/2022]
Abstract
Circulating blood glucocorticoid levels are dynamic and responsive to stimuli that impact autonomic function. In the brain stem, vagal afferent terminals release the excitatory neurotransmitter glutamate to neurons in the nucleus of the solitary tract (NTS). Vagal afferents integrate direct visceral signals and circulating hormones with ongoing NTS activity to control autonomic function and behavior. Here, we investigated the effects of corticosterone (CORT) on glutamate signaling in the NTS using patch-clamp electrophysiology on brain stem slices containing the NTS and central afferent terminals from male C57BL/6 mice. We found that CORT rapidly decreased both action potential-evoked and spontaneous glutamate signaling. The effects of CORT were phenocopied by dexamethasone and blocked by mifepristone, consistent with glucocorticoid receptor (GR)-mediated signaling. While mRNA for GR was present in both the NTS and vagal afferent neurons, selective intracellular quenching of G protein signaling in postsynaptic NTS neurons eliminated the effects of CORT. We then investigated the contribution of retrograde endocannabinoid signaling, which has been reported to transduce nongenomic GR effects. Pharmacological or genetic elimination of the cannabinoid type 1 receptor signaling blocked CORT suppression of glutamate release. Together, our results detail a mechanism, whereby the NTS integrates endocrine CORT signals with fast neurotransmission to control autonomic reflex pathways.
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Affiliation(s)
- Forrest J Ragozzino
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
| | - Rachel A Arnold
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
| | - Cody W Kowalski
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
| | - Marina I Savenkova
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
| | - Ilia N Karatsoreos
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington.,Department of Psychological and Brain Sciences, University of Massachusetts Amherst, Amherst, Massachusetts
| | - James H Peters
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
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11
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Cummings KJ, Leiter JC. Take a deep breath and wake up: The protean role of serotonin preventing sudden death in infancy. Exp Neurol 2020; 326:113165. [PMID: 31887304 PMCID: PMC6956249 DOI: 10.1016/j.expneurol.2019.113165] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 12/14/2019] [Accepted: 12/26/2019] [Indexed: 01/24/2023]
Abstract
Recordings from infants who died suddenly and unexpectedly demonstrate the occurrence of recurring apneas, ineffective gasping, and finally, failure to restore eupnea and arouse prior to death. Immunohistochemical and autoradiographic data demonstrate a constellation of serotonergic defects in the caudal raphe nuclei in infants who died of Sudden Infant Death Syndrome (SIDS). The purpose of this review is to synthesize what is known about adaptive responses of the infant to severely hypoxic conditions, which unleash a flood of neuromodulators that inhibit cardiorespiratory function, thermogenesis, and arousal and the emerging role of serotonin, which combats this cardiorespiratory inhibition to foster autoresuscitation, eupnea, and arousal to ensure survival following an hypoxic episode. The laryngeal and carotid body chemoreflexes are potent in newborns and infants, and both reflexes can induce apnea and bradycardia, which may be adaptive initially, but must be terminated if an infant is to survive. Serotonin has a unique ability to touch on each of the processes that may be required to recover from hypoxic reflex apnea: gasping, the restoration of heart rate and blood pressure, termination of apneas and, eventually, stimulation of eupnea and arousal. Recurrent apneic events, bradycardia, ineffective gasping and a failure to terminate apneas and restore eupnea are observed in animals harboring defects in the caudal serotonergic system models - all of these phenotypes are reminiscent of and compatible with the cardiorespiratory recordings made in infants who subsequently died of SIDS. The caudal serotonergic system provides an organized, multi-pronged defense against reflex cardiorespiratory inhibition and the hypoxia that accompanies prolonged apnea, bradycardia and hypotension, and any deficiency of caudal serotonergic function will increase the propensity for sudden unexplained infant death.
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Affiliation(s)
- Kevin J Cummings
- Department of Biomedical Sciences, University of Missouri-Columbia, Dalton Cardiovascular Research Center, 134 Research Park Drive, Columbia, MO 65203, USA
| | - James C Leiter
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, One Rope Ferry Road, Hanover, NH 03755, USA.
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12
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Donnelly WT, Haynes RL, Commons KG, Erickson DJ, Panzini CM, Xia L, Han QJ, Leiter JC. Prenatal intermittent hypoxia sensitizes the laryngeal chemoreflex, blocks serotoninergic shortening of the reflex, and reduces 5-HT 3 receptor binding in the NTS in anesthetized rat pups. Exp Neurol 2020; 326:113166. [PMID: 31887303 PMCID: PMC7028519 DOI: 10.1016/j.expneurol.2019.113166] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 12/14/2019] [Accepted: 12/26/2019] [Indexed: 10/25/2022]
Abstract
We tested the hypothesis that exposure to intermittent hypoxia (IH) during pregnancy would prolong the laryngeal chemoreflex (LCR) and diminish the capacity of serotonin (5-hydroxytryptamine; 5-HT) to terminate the LCR. Prenatal exposure to IH was associated with significant prolongation of the LCR in younger, anesthetized, postnatal day (P) rat pups age P8 to P16 compared to control, room air (RA)-exposed rat pups of the same age. Serotonin microinjected into the NTS shortened the LCR in rat pups exposed to RA during gestation, but 5-HT failed to shorten the LCR in rat pups exposed to prenatal IH. Given these observations, we tested the hypothesis that prenatal hypoxia would decrease binding to 5-HT3 receptors in the nucleus of the solitary tract (NTS) where 5-HT acts to shorten the LCR. Serotonin 3 receptor binding was reduced in younger rat pups exposed to IH compared to control, RA-exposed rat pups in the age range P8 to P12. Serotonin 3 receptor binding was similar in older animals (P18-P24) regardless of gas exposure during gestation. The failure of the 5-HT injected into the NTS to shorten the LCR was correlated with a developmental decrease in 5-HT3 receptor binding in the NTS associated with exposure to prenatal IH. In summary, prenatal IH sensitized reflex apnea and blunted processes that terminate reflex apneas in neonatal rat pups, processes that are essential to prevent death following apneas such as those seen in babies who died of SIDS.
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Affiliation(s)
- William T Donnelly
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, One Rope Ferry Road, Hanover, NH 03755, United States of America
| | - Robin L Haynes
- Department of Pathology, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, United States of America
| | - Kathryn G Commons
- Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital and Harvard Medical School, United States of America
| | - Drexel J Erickson
- Department of Pathology, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, United States of America
| | - Chris M Panzini
- Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital and Harvard Medical School, United States of America
| | - Luxi Xia
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, One Rope Ferry Road, Hanover, NH 03755, United States of America
| | - Q Joyce Han
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, One Rope Ferry Road, Hanover, NH 03755, United States of America
| | - J C Leiter
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, One Rope Ferry Road, Hanover, NH 03755, United States of America.
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13
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Abstract
Objective: This review discusses the relationship between cannabis use and psychotic, bipolar, depressive, and anxiety disorders, as well as suicide. It summarizes epidemiological evidence from cross-sectional and long-term prospective studies and considers possible etiological mechanisms. Methods: Systematic reviews and methodologically robust studies in the field (from inception to February 2019) were identified using a comprehensive search of Medline, PsychINFO, and Embase and summarized using a narrative synthesis. Results: Consistent evidence, both from observational and experimental studies, has confirmed the important role of cannabis use in the initiation and persistence of psychotic disorders. The size of the effect is related to the extent of cannabis use, with greater risk for early cannabis use and use of high-potency varieties and synthetic cannabinoids. Accumulating evidence suggests that frequent cannabis use also increases the risk for mania as well as for suicide. However, the effect on depression is less clear and findings on anxiety are contradictory with only a few methodologically robust studies. Furthermore, the relationship with common mental disorders may involve reverse causality, as depression and anxiety are reported to lead to greater cannabis consumption in some studies. Pathogenetic mechanisms focus on the effect of tetrahydrocannabinol (THC, the main psychoactive ingredient of cannabis) interacting with genetic predisposition and perhaps other environmental risk factors. Cannabidiol (CBD), the other important ingredient of traditional cannabis, ameliorates the psychotogenic effects of THC but is absent from the high-potency varieties that are increasingly available. Conclusions: The evidence that heavy use of high-THC/low-CBD types of cannabis increases the risk of psychosis is sufficiently strong to merit public health education. Evidence of similar but smaller effects in mania and suicide is growing, but is not convincing for depression and anxiety. There is much current interest in the possibility that CBD may be therapeutically useful.
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Affiliation(s)
- Lucia Sideli
- Institute of Psychiatry, Psychology, and Neuroscience, King's College, London, UK.,Department of Biomedicine, Neurosciences, and Advanced Diagnostic, University of Palermo, Palermo, Italy
| | - Harriet Quigley
- Institute of Psychiatry, Psychology, and Neuroscience, King's College, London, UK.,South London and Maudsley NHS Trust Biomedical Research Centre, London, UK
| | - Caterina La Cascia
- Department of Biomedicine, Neurosciences, and Advanced Diagnostic, University of Palermo, Palermo, Italy
| | - Robin M Murray
- Institute of Psychiatry, Psychology, and Neuroscience, King's College, London, UK.,Department of Biomedicine, Neurosciences, and Advanced Diagnostic, University of Palermo, Palermo, Italy.,South London and Maudsley NHS Trust Biomedical Research Centre, London, UK
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14
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Gambino G, Rizzo V, Giglia G, Ferraro G, Sardo P. Cannabinoids, TRPV and nitric oxide: the three ring circus of neuronal excitability. Brain Struct Funct 2019; 225:1-15. [PMID: 31792694 DOI: 10.1007/s00429-019-01992-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 11/22/2019] [Indexed: 12/13/2022]
Abstract
Endocannabinoid system is considered a relevant player in the regulation of neuronal excitability, since it contributes to maintaining the balance of the synaptic ionic milieu. Perturbations to bioelectric conductances have been implicated in the pathophysiological processes leading to hyperexcitability and epileptic seizures. Cannabinoid influence on neurosignalling is exerted on classic receptor-mediated mechanisms or on further molecular targets. Among these, transient receptor potential vanilloid (TRPV) are ionic channels modulated by cannabinoids that are involved in the transduction of a plethora of stimuli and trigger fundamental downstream pathways in the post-synaptic site. In this review, we aim at providing a brief summary of the most recent data about the cross-talk between cannabinoid system and TRPV channels, drawing attention on their role on neuronal hyperexcitability. Then, we aim to unveil a plausible point of interaction between these neural signalling systems taking into consideration nitric oxide, a gaseous molecule inducing profound modifications to neural performances. From this novel perspective, we struggle to propose innovative cellular mechanisms in the regulation of hyperexcitability phenomena, with the goal of exploring plausible CB-related mechanisms underpinning epileptic seizures.
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Affiliation(s)
- Giuditta Gambino
- Department of Experimental Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), Sezione di Fisiologia Umana G. Pagano, University of Palermo, Corso Tukory 129, Palermo, Italy.
| | - Valerio Rizzo
- Department of Experimental Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), Sezione di Fisiologia Umana G. Pagano, University of Palermo, Corso Tukory 129, Palermo, Italy
| | - Giuseppe Giglia
- Department of Experimental Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), Sezione di Fisiologia Umana G. Pagano, University of Palermo, Corso Tukory 129, Palermo, Italy
| | - Giuseppe Ferraro
- Department of Experimental Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), Sezione di Fisiologia Umana G. Pagano, University of Palermo, Corso Tukory 129, Palermo, Italy
| | - Pierangelo Sardo
- Department of Experimental Biomedicine, Neuroscience and Advanced Diagnostics (Bi.N.D.), Sezione di Fisiologia Umana G. Pagano, University of Palermo, Corso Tukory 129, Palermo, Italy
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15
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Abstract
The transient receptor potential vanilloid 1 (TRPV1) is densely expressed in spinal sensory neurons as well as in cranial sensory neurons, including their central terminal endings. Recent work in the less familiar cranial sensory neurons, despite their many similarities with spinal sensory neurons, suggest that TRPV1 acts as a calcium channel to release a discrete population of synaptic vesicles. The modular and independent regulation of release offers new questions about nanodomain organization of release and selective actions of G protein–coupled receptors.
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Affiliation(s)
- Michael C. Andresen
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR, 97239, USA
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16
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Fawley JA, Andresen MC. Distinct Calcium Sources Define Compartmentalized Synaptic Signaling Domains. Neuroscientist 2019; 25:408-419. [PMID: 31375041 DOI: 10.1177/1073858419863771] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Nervous system communication relies on neurotransmitter release for synaptic transmission between neurons. Neurotransmitter is contained within vesicles in presynaptic terminals and intraterminal calcium governs the fundamental step of their release into the synaptic cleft. Despite a common dependence on calcium, synaptic transmission and its modulation varies highly across the nervous system. The precise mechanisms that underlie this heterogeneity, however, remain unclear. The present review highlights recent data that reveal vesicles sourced from separate pools define discrete modes of release. A rich diversity of regulatory machinery may further distinguish the different forms of vesicle release, including presynaptic proteins involved in trafficking, alignment, and exocytosis. These multiple vesicle release mechanisms and vesicle pools likely depend on the arrangement of vesicles in relation to specific calcium entry pathways that create compartmentalized spheres of calcium influence (i.e., domains). This diversity permits release specialization. This review details examples of how individual neurons rely on multiple calcium sources and unique regulatory schemes to provide differential release and discrete modulation of neurotransmitter release from specific vesicle pools-as part of network signal integration.
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Affiliation(s)
- Jessica A Fawley
- Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, OR, USA
| | - Michael C Andresen
- Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, OR, USA
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17
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5-HT 3R-sourced calcium enhances glutamate release from a distinct vesicle pool. Brain Res 2019; 1721:146346. [PMID: 31348913 DOI: 10.1016/j.brainres.2019.146346] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 06/18/2019] [Accepted: 07/21/2019] [Indexed: 01/01/2023]
Abstract
The serotonin 3 receptor (5-HT3R) is a calcium-permeant channel heterogeneously expressed in solitary tract (ST) afferents. ST afferents synapse in the nucleus of the solitary tract (NTS) and rely on a mix of voltage-dependent calcium channels (CaVs) to control synchronous glutamate release (ST-EPSCs). CaV activation triggers additional, delayed release of glutamate (asynchronous EPSCs) that trails after the ST-EPSCs but only from afferents expressing the calcium-permeable, transient receptor potential vanilloid type 1 receptor (TRPV1). Most afferents express TRPV1 and have high rates of spontaneous glutamate release (sEPSCs) that is independent of CaVs. Here, we tested whether 5-HT3R-sourced calcium contributes to these different forms of glutamate release in horizontal NTS slices from rats. The 5-HT3R selective agonist, m-chlorophenyl biguanide hydrochloride (PBG), enhanced sEPSCs and/or delayed the arrival times of ST-EPSCs (i.e. increased latency). The specific 5-HT3R antagonist, ondansetron, attenuated these effects consistent with direct activation of 5-HT3Rs. PBG did not alter ST-EPSC amplitude or asynchronous EPSCs. These independent actions suggest two distinct 5-HT3R locations; axonal expression that impedes conduction and terminal expression that mobilizes a spontaneous vesicle pool. Calcium chelation with EGTA-AM attenuated the frequency of 5-HT3R-activated sEPSCs by half. The mixture of chelation-sensitive and resistant sEPSCs suggests that 5-HT3R-activated vesicles span calcium diffusion distances that are both distal (micro-) and proximal (nanodomains) to the channel. Our results demonstrate that the calcium domains of 5-HT3Rs do not overlap other calcium sources or their respective vesicle pools. 5-HT3Rs add a unique calcium source on ST afferents as part of multiple independent synaptic signaling mechanisms.
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18
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Asaoka R, Ohi Y, Miyazawa K, Goto S, Haji A. Involvement of presynaptic TRPV1 channels in prostaglandin E 2-induced facilitation of spontaneous synaptic transmission in the rat spinal trigeminal subnucleus caudalis. Brain Res 2019; 1715:115-125. [PMID: 30898677 DOI: 10.1016/j.brainres.2019.03.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 01/10/2019] [Accepted: 03/16/2019] [Indexed: 10/27/2022]
Abstract
Prostaglandin E2 (PGE2) synthesized in the central nervous system influences various physiological functions including nociception. Recently, we have demonstrated that PGE2 facilitates spontaneous synaptic transmission through presynaptic EP1 receptors in the spinal trigeminal subnucleus caudalis (Vc) neurons that receive nociceptive signals from the orofacial area. Increasing evidence suggests that the action of PGE2 is related to activation of transient receptor potential vanilloid 1 (TRPV1) channels. The present study investigated whether TRPV1 channels contribute to the facilitatory effect of PGE2 on synaptic transmission in the Vc neurons. Spontaneous excitatory and inhibitory postsynaptic currents (sEPSCs and sIPSCs) were recorded from Vc neurons in the rat brainstem slice by whole-cell patch-clamp mode. Superfusion of capsaicin (0.3, 1.0 μM) concentration-dependently increased the frequency of both sEPSCs and sIPSCs without any significant effect on their amplitude. The effect of capsaicin was completely abolished by a TRPV1 channel blocker AMG9810 (0.1 μM). PGE2 (5.0 μM) increased the frequency of sEPSCs and sIPSCs. This facilitatory effect of PGE2 was attenuated by AMG9810 and in neurons desensitized by repeated application of capsaicin. While a low concentration of either PGE2 (1.0 μM) or capsaicin (0.1 μM) had an insignificant effect on the sEPSCs and sIPSCs, co-application of these drugs increased their frequency. The present study demonstrated involvement of the presynaptic TRPV1 channels in PGE2-induced facilitation of spontaneous synaptic transmissions and suggests interaction of PGE2 with TRPV1 channels in modification of nociceptive signals from the orofacial area to the Vc neurons.
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Affiliation(s)
- Ryo Asaoka
- Laboratory of Neuropharmacology, School of Pharmacy, Aichi Gakuin University, Nagoya, Japan; Department of Orthodontics, School of Dentistry, Aichi Gakuin University, Nagoya, Japan
| | - Yoshiaki Ohi
- Laboratory of Neuropharmacology, School of Pharmacy, Aichi Gakuin University, Nagoya, Japan
| | - Ken Miyazawa
- Department of Orthodontics, School of Dentistry, Aichi Gakuin University, Nagoya, Japan
| | - Shigemi Goto
- Department of Orthodontics, School of Dentistry, Aichi Gakuin University, Nagoya, Japan
| | - Akira Haji
- Laboratory of Neuropharmacology, School of Pharmacy, Aichi Gakuin University, Nagoya, Japan.
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19
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TRPV1 mediates the anticonvulsant effects of acetaminophen in mice. Epilepsy Res 2018; 145:153-159. [DOI: 10.1016/j.eplepsyres.2018.06.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 06/19/2018] [Accepted: 06/30/2018] [Indexed: 12/16/2022]
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20
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Role of the Endocannabinoid System in the Pathophysiology of Schizophrenia: Implications for Pharmacological Intervention. CNS Drugs 2018; 32:605-619. [PMID: 30022465 DOI: 10.1007/s40263-018-0539-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The term schizophrenia describes a group of multifaceted psychiatric conditions causing significant impairment of the quality of life of affected patients. Although multiple pharmacological treatment options exist, e.g. first- or second-generation antipsychotics, these therapeutics often cause disturbing side effects, such as extrapyramidal symptoms, prolactin increase, sexual dysfunction and/or metabolic syndrome. Furthermore, cognitive impairments and negative symptoms, two factors significantly influencing the course and outcome, are not sufficiently addressed by the available antipsychotics. Since its discovery, multiple clinical and preclinical studies have linked the endocannabinoid system to schizophrenia. Both the endocannabinoid anandamide and the cannabinoid CB1 receptor are deeply linked to underlying disease processes. Based hereon, clinical trials in schizophrenia have explored cannabidiol, a primary component of Cannabis sativa, and rimonabant, a partial antagonist to the CB1 receptor. While the latter did not reveal positive results, cannabidiol significantly ameliorated psychotic symptoms, which was associated with an increase in anandamide serum levels. However, the exact mechanisms of the antipsychotic effects of cannabidiol are not fully understood, and, furthermore, only a limited number of clinical trials in humans have been concluded to date. Thus, the level of proof of safety and efficacy required to approve the therapeutic use of cannabidiol in schizophrenia is currently lacking. However, cannabidiol is a promising candidate as an effective and mechanistically different antipsychotic treatment with a favourable side-effect profile. We therefore conclude that further studies are urgently needed to clarify the antipsychotic effects and safety profile of cannabidiol, and to fully explore its potential antipsychotic mechanism.
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21
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Mohammed M, Madden CJ, Andresen MC, Morrison SF. Activation of TRPV1 in nucleus tractus solitarius reduces brown adipose tissue thermogenesis, arterial pressure, and heart rate. Am J Physiol Regul Integr Comp Physiol 2018; 315:R134-R143. [PMID: 29590555 DOI: 10.1152/ajpregu.00049.2018] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The sympathetic nerve activity (SNA) to brown adipose tissue (BAT) regulates BAT thermogenesis to defend body temperature in cold environments or to produce fever during immune responses. The vagus nerve contains afferents that inhibit the BAT SNA and BAT thermogenesis evoked by skin cooling. We sought to determine whether activation of transient receptor potential vanilloid 1 (TRPV1) channels in the nucleus tractus solitarius (NTS), which are prominently expressed in unmyelinated vagal afferents, would affect cold-evoked BAT thermogenesis, cardiovascular parameters, or their vagal afferent-evoked responses. In urethane-chloralose-anesthetized rats, during skin cooling, nanoinjection of the TRPV1-agonist resiniferatoxin in NTS decreased BAT SNA (from 695 ± 195% of baseline during cooling to 103 ± 8% of baseline after resiniferatoxin), BAT temperature (-0.8 ± 0.1°C), expired CO2 (-0.3 ± 0.04%), mean arterial pressure (MAP; -20 ± 5 mmHg), and heart rate (-44 ± 11 beats/min). Pretreatment of NTS with the TRPV1 antagonist capsazepine prevented these resiniferatoxin-mediated effects. Intravenous injection of the TRPV1 agonist dihydrocapsaicin also decreased all the measured variables (except MAP). Bilateral cervical or subdiaphragmatic vagotomy attenuated the decreases in BAT SNA and thermogenesis evoked by nanoinjection of resiniferatoxin in NTS but did not prevent the decreases in BAT SNA and BAT thermogenesis evoked by intravenous dihydrocapsaicin. We conclude that activation of TRPV1 channels in the NTS of vagus nerve intact rats inhibits BAT SNA and decreases BAT metabolism, blood pressure, and heart rate. In contrast, the inhibition of BAT thermogenesis following systemic administration of dihydrocapsaicin does not require vagal afferent activity, consistent with a nonvagal pathway through which systemic TRPV1 agonists can inhibit BAT thermogenesis.
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Affiliation(s)
- Mazher Mohammed
- Department of Neurological Surgery, Oregon Health & Science University , Portland, Oregon
| | - Christopher J Madden
- Department of Neurological Surgery, Oregon Health & Science University , Portland, Oregon
| | - Michael C Andresen
- Department of Physiology and Pharmacology, Oregon Health & Science University , Portland, Oregon
| | - Shaun F Morrison
- Department of Neurological Surgery, Oregon Health & Science University , Portland, Oregon
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22
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Huda R, Chang Z, Do J, McCrimmon DR, Martina M. Activation of astrocytic PAR1 receptors in the rat nucleus of the solitary tract regulates breathing through modulation of presynaptic TRPV1. J Physiol 2018; 596:497-513. [PMID: 29235097 DOI: 10.1113/jp275127] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 12/06/2017] [Indexed: 01/01/2023] Open
Abstract
KEY POINTS In the rat nucleus of the solitary tract (NTS), activation of astrocytic proteinase-activated receptor 1 (PAR1) receptors leads to potentiation of neuronal synaptic activity by two mechanisms, one TRPV1-dependent and one TRPV1-independent. PAR1-dependent activation of presynaptic TRPV1 receptors facilitates glutamate release onto NTS neurons. The TRPV1-dependent mechanism appears to rely on astrocytic release of endovanilloid-like molecules. A subset of NTS neurons excited by PAR1 directly project to the rostral ventral respiratory group. The PAR1 initiated, TRPV1-dependent modulation of synaptic transmission in the NTS contributes to regulation of breathing. ABSTRACT Many of the cellular and molecular mechanisms underlying astrocytic modulation of synaptic function remain poorly understood. Recent studies show that G-protein coupled receptor-mediated astrocyte activation modulates synaptic transmission in the nucleus of the solitary tract (NTS), a brainstem nucleus that regulates crucial physiological processes including cardiorespiratory activity. By using calcium imaging and patch clamp recordings in acute brain slices of wild-type and TRPV1-/- rats, we show that activation of proteinase-activated receptor 1 (PAR1) in NTS astrocytes potentiates presynaptic glutamate release on NTS neurons. This potentiation is mediated by both a TRPV1-dependent and a TRPV1-independent mechanism. The TRPV1-dependent mechanism appears to require release of endovanilloid-like molecules from astrocytes, which leads to subsequent potentiation of presynaptic glutamate release via activation of presynaptic TRPV1 channels. Activation of NTS astrocytic PAR1 receptors elicits cFOS expression in neurons that project to respiratory premotor neurons and inhibits respiratory activity in control, but not in TRPV1-/- rats. Thus, activation of astrocytic PAR1 receptor in the NTS leads to a TRPV1-dependent excitation of NTS neurons causing a potent modulation of respiratory motor output.
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Affiliation(s)
- Rafiq Huda
- Department of Physiology, Northwestern University Feinberg School of Medicine, 303 E Chicago Ave., Chicago, IL, 60611, USA
| | - Zheng Chang
- Department of Physiology, Northwestern University Feinberg School of Medicine, 303 E Chicago Ave., Chicago, IL, 60611, USA
| | - Jeehaeh Do
- Department of Physiology, Northwestern University Feinberg School of Medicine, 303 E Chicago Ave., Chicago, IL, 60611, USA
| | - Donald R McCrimmon
- Department of Physiology, Northwestern University Feinberg School of Medicine, 303 E Chicago Ave., Chicago, IL, 60611, USA
| | - Marco Martina
- Department of Physiology, Northwestern University Feinberg School of Medicine, 303 E Chicago Ave., Chicago, IL, 60611, USA
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Babiec WE, O'Dell TJ. Novel Ca 2+-dependent mechanisms regulate spontaneous release at excitatory synapses onto CA1 pyramidal cells. J Neurophysiol 2017; 119:597-607. [PMID: 29142096 DOI: 10.1152/jn.00628.2017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Although long thought to simply be a source of synaptic noise, spontaneous, action potential-independent release of neurotransmitter from presynaptic terminals has multiple roles in synaptic function. We explored whether and to what extent the two predominantly proposed mechanisms for explaining spontaneous release, stochastic activation of voltage-gated Ca2+ channels (VGCCs) or activation of Ca2+-sensing receptors (CaSRs) by extracellular Ca2+, played a role in the sensitivity of spontaneous release to the level of extracellular Ca2+ concentration at excitatory synapses at CA1 pyramidal cells of the adult male mouse hippocampus. Blocking VGCCs with Cd2+ had no effect on spontaneous release, ruling out stochastic activation of VGCCs. Although divalent cation agonists of CaSRs, Co2+ and Mg2+, dramatically enhanced miniature excitatory postsynaptic current (mEPSC) frequency, potent positive and negative allosteric modulators of CaSRs had no effect. Moreover, immunoblot analysis of hippocampal lysates failed to detect CaSR expression, ruling out the CaSR. Instead, the increase in mEPSC frequency induced by Co2+ and Mg2+ was mimicked by lowering postsynaptic Ca2+ levels with BAPTA. Together, our results suggest that a reduction in intracellular Ca2+ may trigger a homeostatic-like compensatory response that upregulates spontaneous transmission at excitatory synapses onto CA1 pyramidal cells in the adult hippocampus. NEW & NOTEWORTHY We show that the predominant theories for explaining the regulation of spontaneous, action potential-independent synaptic release do not explain the sensitivity of this type of synaptic transmission to external Ca2+ concentration at excitatory synapses onto hippocampal CA1 pyramidal cells. In addition, our data indicate that intracellular Ca2+ levels in CA1 pyramidal cells regulate spontaneous release, suggesting that excitatory synapses onto CA1 pyramidal cells may express a novel, rapid form of homeostatic plasticity.
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Affiliation(s)
- Walter E Babiec
- Department of Physiology, David Geffen School of Medicine at UCLA , Los Angeles, California
| | - Thomas J O'Dell
- Department of Physiology, David Geffen School of Medicine at UCLA , Los Angeles, California.,UCLA Integrative Center for Learning and Memory, Brain Research Institute, UCLA, Los Angeles, California
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24
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Jamieson BB, Nair BB, Iremonger KJ. Regulation of hypothalamic corticotropin-releasing hormone neurone excitability by oxytocin. J Neuroendocrinol 2017; 29. [PMID: 28872712 DOI: 10.1111/jne.12532] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Revised: 08/30/2017] [Accepted: 08/31/2017] [Indexed: 02/01/2023]
Abstract
Oxytocin (OT) is a neuropeptide that exerts multiple actions throughout the brain and periphery. Within the brain, OT regulates diverse neural populations, including neural networks controlling responses to stress. Local release of OT within the paraventricular nucleus (PVN) of the hypothalamus has been suggested to regulate stress responses by modulating the excitability of neighbouring corticotropin-releasing hormone (CRH) neurones. However, the mechanisms by which OT regulates CRH neurone excitability are unclear. In the present study, we investigated the morphological relationship between OT and CRH neurones and determined the effects of OT on CRH neurone excitability. Morphological analysis revealed that the processes of OT and CRH neurones were highly intermingled within the PVN, possibly allowing for local cell-to-cell cross-talk. Whole-cell patch-clamp recordings from CRH neurones were used to study the impact of OT on postsynaptic excitability and synaptic innervation. Bath-applied OT did not alter CRH neurone holding current, spiking output or any action potential parameters. Recordings of evoked excitatory and inhibitory postsynaptic currents (EPSCs/IPSCs) revealed no net effect of OT on current amplitude; however, subgroups of CRH neurones appeared to respond differentially to OT. Analysis of spontaneous EPSC events uncovered a significant reduction in spontaneous EPSC frequency but no change in spontaneous EPSC amplitude in response to OT. Together, these data demonstrate that OT exerts a subtle modulation of synaptic transmission onto CRH neurones providing one potential mechanism by which OT could suppress CRH neurone excitability and stress axis activity.
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Affiliation(s)
- B B Jamieson
- Department of Physiology, Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand
| | - B B Nair
- Department of Physiology, Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand
| | - K J Iremonger
- Department of Physiology, Centre for Neuroendocrinology, University of Otago, Dunedin, New Zealand
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Distinct Calcium Sources Support Multiple Modes of Synaptic Release from Cranial Sensory Afferents. J Neurosci 2017; 36:8957-66. [PMID: 27559176 DOI: 10.1523/jneurosci.1028-16.2016] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 07/09/2016] [Indexed: 01/24/2023] Open
Abstract
UNLABELLED Most craniosensory afferents have unmyelinated axons expressing TRP Vanilloid 1 (TRPV1) receptors in synaptic terminals at the solitary tract nucleus (NTS). Neurotransmission from these synapses is characterized by substantial asynchronous EPSCs following action potential-synched EPSCs and high spontaneous rates that are thermally sensitive. The present studies blocked voltage-activated calcium channels (CaV) using the nonselective CaV blocker Cd(2+) or the specific N-type blocker ω-conotoxin GVIA to examine the calcium dependence of the synchronous, asynchronous, spontaneous, and thermally gated modes of release. In rat brainstem slices containing caudal NTS, shocks to the solitary tract (ST) triggered synchronous ST-EPSCs and trailing asynchronous EPSCs. Cd(2+) or GVIA efficiently reduced both synchronous and asynchronous EPSCs without altering spontaneous or thermal-evoked transmission. Activation of TRPV1 with either the selective agonist resiniferatoxin (150 pm) or temperature augmented basal sEPSC rates but failed to alter the synchronous or asynchronous modes of release. These data indicate that calcium sourced through TRPV1 has no access to the synchronous or asynchronous release mechanism(s) and conversely that CaV-sourced calcium does not interact with the thermally evoked mode of release. Buffering intracellular calcium with EGTA-AM or BAPTA-AM reduced asynchronous EPSC rates earlier and to a greater extent than synchronous ST-EPSC amplitudes without altering sEPSCs or thermal sensitivity. Buffering therefore distinguishes asynchronous vesicles as possessing a highly sensitive calcium sensor located perhaps more distant from CaV than synchronous vesicles or thermally evoked vesicles from TRPV1. Together, our findings suggest separate mechanisms of release for spontaneous, asynchronous and synchronous vesicles that likely reside in unique, spatially separated vesicle domains. SIGNIFICANCE STATEMENT Most craniosensory fibers release glutamate using calcium entry from two sources: CaVs and TRPV1. We demonstrate that calcium segregation distinguishes three vesicle release mechanisms. Most surprisingly, asynchronous release is associated with CaV and not TRPV1 calcium entry. This reveals that asynchronous release is an additional and separate phenotypic marker of unmyelinated afferents rather than operated by TRPV1. The functional independence of the two calcium sources expands the regulatory repertoire of transmission and imbues these inputs with additional modulation targets for synaptic release not present at conventional CaV synapses. Peptides and lipid mediators may target one or both of these calcium sources at afferent terminals within the solitary tract nucleus to independently modify release from distinct, functionally segregated vesicle pools.
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Sandler RA, Fetterhoff D, Hampson RE, Deadwyler SA, Marmarelis VZ. Cannabinoids disrupt memory encoding by functionally isolating hippocampal CA1 from CA3. PLoS Comput Biol 2017; 13:e1005624. [PMID: 28686594 PMCID: PMC5521875 DOI: 10.1371/journal.pcbi.1005624] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 07/21/2017] [Accepted: 06/13/2017] [Indexed: 01/02/2023] Open
Abstract
Much of the research on cannabinoids (CBs) has focused on their effects at the molecular and synaptic level. However, the effects of CBs on the dynamics of neural circuits remains poorly understood. This study aims to disentangle the effects of CBs on the functional dynamics of the hippocampal Schaffer collateral synapse by using data-driven nonparametric modeling. Multi-unit activity was recorded from rats doing an working memory task in control sessions and under the influence of exogenously administered tetrahydrocannabinol (THC), the primary CB found in marijuana. It was found that THC left firing rate unaltered and only slightly reduced theta oscillations. Multivariate autoregressive models, estimated from spontaneous spiking activity, were then used to describe the dynamical transformation from CA3 to CA1. They revealed that THC served to functionally isolate CA1 from CA3 by reducing feedforward excitation and theta information flow. The functional isolation was compensated by increased feedback excitation within CA1, thus leading to unaltered firing rates. Finally, both of these effects were shown to be correlated with memory impairments in the working memory task. By elucidating the circuit mechanisms of CBs, these results help close the gap in knowledge between the cellular and behavioral effects of CBs. Research into cannabinoids (CBs) over the last several decades has found that they induce a large variety of oftentimes opposing effects on various neuronal receptors and processes. Due to this plethora of effects, disentangling how CBs influence neuronal circuits has proven challenging. This paper contributes to our understanding of the circuit level effects of CBs by using data driven modeling to examine how THC affects the input-output relationship in the Schaffer collateral synapse in the hippocampus. It was found that THC functionally isolated CA1 from CA3 by reducing feedforward excitation and theta information flow while simultaneously increasing feedback excitation within CA1. By elucidating the circuit mechanisms of CBs, these results help close the gap in knowledge between the cellular and behavioral effects of CBs.
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Affiliation(s)
- Roman A. Sandler
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, United States of America
- * E-mail:
| | - Dustin Fetterhoff
- Department of Physiology & Pharmacology, Wake Forest University, Winston-Salem, North Carolina, United States of America
| | - Robert E. Hampson
- Department of Physiology & Pharmacology, Wake Forest University, Winston-Salem, North Carolina, United States of America
| | - Sam A. Deadwyler
- Department of Physiology & Pharmacology, Wake Forest University, Winston-Salem, North Carolina, United States of America
| | - Vasilis Z. Marmarelis
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, United States of America
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27
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Dynasore blocks evoked release while augmenting spontaneous synaptic transmission from primary visceral afferents. PLoS One 2017; 12:e0174915. [PMID: 28358887 PMCID: PMC5373620 DOI: 10.1371/journal.pone.0174915] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 03/17/2017] [Indexed: 11/27/2022] Open
Abstract
The recycling of vesicle membrane fused during exocytosis is essential to maintaining neurotransmission. The GTPase dynamin is involved in pinching off membrane to complete endocytosis and can be inhibited by dynasore resulting in activity-dependent depletion of release-competent synaptic vesicles. In rat brainstem slices, we examined the effects of dynasore on three different modes of glutamate release–spontaneous, evoked, and asynchronous release–at solitary tract (ST) inputs to neurons in the nucleus of the solitary tract (NTS). Intermittent bursts of stimuli to the ST interspersed with pauses in stimulation allowed examination of these three modes in each neuron continuously. Application of 100 μM dynasore rapidly increased the spontaneous EPSC (sEPSC) frequency which was followed by inhibition of both ST-evoked EPSCs (ST-EPSC) as well as asynchronous EPSCs. The onset of ST-EPSC failures was not accompanied by amplitude reduction–a pattern more consistent with conduction block than reduced probability of vesicle release. Neither result suggested that dynasore interrupted endocytosis. The dynasore response profile resembled intense presynaptic TRPV1 activation. The TRPV1 antagonist capsazepine failed to prevent dynasore increases in sEPSC frequency but did prevent the block of the ST-EPSC. In contrast, the TRPV1 antagonist JNJ 17203212 prevented both actions of dynasore in neurons with TRPV1-expressing ST inputs. In a neuron lacking TRPV1-expressing ST inputs, however, dynasore promptly increased sEPSC rate followed by block of ST-evoked EPSCs. Together our results suggest that dynasore actions on ST-NTS transmission are TRPV1-independent and changes in glutamatergic transmission are not consistent with changes in vesicle recycling and endocytosis.
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Khlaifia A, Matias I, Cota D, Tell F. Nutritional status-dependent endocannabinoid signalling regulates the integration of rat visceral information. J Physiol 2017; 595:3267-3285. [PMID: 28233325 DOI: 10.1113/jp273484] [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: 09/16/2016] [Accepted: 02/21/2017] [Indexed: 12/27/2022] Open
Abstract
KEY POINTS Vagal sensory inputs transmit information from the viscera to brainstem neurones located in the nucleus tractus solitarii to set physiological parameters. These excitatory synapses exhibit a CB1 endocannabinoid-induced long-term depression (LTD) triggered by vagal fibre stimulation. We investigated the impact of nutritional status on long-term changes in this long-term synaptic plasticity. Food deprivation prevents LTD induction by disrupting CB1 receptor signalling. Short-term refeeding restores the capacity of vagal synapses to express LTD. Ghrelin and cholecystokinin, respectively released during fasting and refeeding, play a key role in the control of LTD via the activation of energy sensing pathways such as AMPK and the mTOR and ERK pathways. ABSTRACT Communication form the viscera to the brain is essential to set physiological homoeostatic parameters but also to drive more complex behaviours such as mood, memory and emotional states. Here we investigated the impact of the nutritional status on long-term changes in excitatory synaptic transmission in the nucleus tractus solitarii, a neural hub integrating visceral signals. These excitatory synapses exhibit a CB1 endocannabinoid (eCB)-induced long-term depression (LTD) triggered by vagal fibre stimulation. Since eCB signalling is known to be an important component of homoeostatic regulation of the body and is regulated during various stressful conditions, we tested the hypothesis that food deprivation alters eCB signalling in central visceral afferent fibres. Food deprivation prevents eCB-LTD induction due to the absence of eCB signalling. This loss was reversed by blockade of ghrelin receptors. Activation of the cellular fuel sensor AMP-activated protein kinase or inhibition of the mechanistic target of rapamycin pathway abolished eCB-LTD in free-fed rats. Signals associated with energy surfeit, such as short-term refeeding, restore eCB-LTD induction, which in turn requires activation of cholecystokinin receptors and the extracellular signal-regulated kinase pathway. These data suggest a tight link between eCB-LTD in the NTS and nutritional status and shed light on the key role of eCB in the integration of visceral information.
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Affiliation(s)
- Abdessattar Khlaifia
- Aix-Marseille Université, CNRS, CRN2M, UMR 7286, 51 Boulevard Pierre Dramard, 13344, Marseille, France
| | - Isabelle Matias
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000, Bordeaux, France.,University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000, Bordeaux, France
| | - Daniela Cota
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000, Bordeaux, France.,University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000, Bordeaux, France
| | - Fabien Tell
- Aix-Marseille Université, CNRS, CRN2M, UMR 7286, 51 Boulevard Pierre Dramard, 13344, Marseille, France
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Abstract
An agonist that acts through a single receptor can activate numerous signaling pathways. Recent studies have suggested that different ligands can differentially activate these pathways by stabilizing a limited range of receptor conformations, which in turn preferentially drive different downstream signaling cascades. This concept, termed "biased signaling" represents an exciting therapeutic opportunity to target specific pathways that elicit only desired effects, while avoiding undesired effects mediated by different signaling cascades. The cannabinoid receptors CB1 and CB2 each activate multiple pathways, and evidence is emerging for bias within these pathways. This review will summarize the current evidence for biased signaling through cannabinoid receptor subtypes CB1 and CB2.
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Affiliation(s)
- Mikkel Søes Ibsen
- Department of Pharmacology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Mark Connor
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, 2 Technology Place, Macquarie University, New South Wales, Australia
| | - Michelle Glass
- Department of Pharmacology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
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30
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Carletti F, Gambino G, Rizzo V, Ferraro G, Sardo P. Involvement of TRPV1 channels in the activity of the cannabinoid WIN 55,212-2 in an acute rat model of temporal lobe epilepsy. Epilepsy Res 2016; 122:56-65. [PMID: 26970948 DOI: 10.1016/j.eplepsyres.2016.02.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 01/18/2016] [Accepted: 02/09/2016] [Indexed: 10/21/2022]
Abstract
The exogenous cannabinoid agonist WIN 55,212-2, (R)-(+)-[2,3-dihydro-5-methyl-3-(4-morpholinylmethyl) pyrrolo[1,2,3-de]-1,4-benzoxazin-6-Yl]-1-naphthalenylmethanone (WIN), has revealed to play a role on modulating the hyperexcitability phenomena in the hippocampus. Cannabinoid-mediated mechanisms of neuroprotection have recently been found to imply the modulation of transient receptor potential vanilloid 1 (TRPV1), a cationic channel subfamily that regulate synaptic excitation. In our study, we assessed the influence of pharmacological manipulation of TRPV1 function, alone and on WIN antiepileptic activity, in the Maximal Dentate Activation (MDA) acute model of temporal lobe epilepsy. Our results showed that the TRPV1 agonist, capsaicin, increased epileptic outcomes; whilst antagonizing TRPV1 with capsazepine exerts a protective role on paroxysmal discharge. When capsaicin is co-administered with WIN effective dose of 10mg/kg is able to reduce its antiepileptic strength, especially on the triggering of MDA response. Accordingly, capsazepine at the protective dose of 2mg/kg managed to potentiate WIN antiepileptic effects, when co-treated. Moreover, WIN subeffective dose of 5mg/kg was turned into effective when capsazepine comes into play. This evidence suggests that systemic administration of TRPV1-active drugs influences electrically induced epilepsy, with a noticeable protective activity for capsazepine. Furthermore, results from the pharmacological interaction with WIN support an interplay between cannabinoid and TRPV1 signaling that could represent a promising approach for a future pharmacological strategy to challenge hyperexcitability-based diseases.
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Affiliation(s)
- Fabio Carletti
- Department of "Biomedicina Sperimentale e Neuroscienze Cliniche" (Bio.Ne.C.), "Sezione di Fisiologia umana G. Pagano", University of Palermo, Corso Tukory 129-90134 Palermo, Italy.
| | - Giuditta Gambino
- Department of "Biomedicina Sperimentale e Neuroscienze Cliniche" (Bio.Ne.C.), "Sezione di Fisiologia umana G. Pagano", University of Palermo, Corso Tukory 129-90134 Palermo, Italy.
| | - Valerio Rizzo
- Department of "Biomedicina Sperimentale e Neuroscienze Cliniche" (Bio.Ne.C.), "Sezione di Fisiologia umana G. Pagano", University of Palermo, Corso Tukory 129-90134 Palermo, Italy.
| | - Giuseppe Ferraro
- Department of "Biomedicina Sperimentale e Neuroscienze Cliniche" (Bio.Ne.C.), "Sezione di Fisiologia umana G. Pagano", University of Palermo, Corso Tukory 129-90134 Palermo, Italy.
| | - Pierangelo Sardo
- Department of "Biomedicina Sperimentale e Neuroscienze Cliniche" (Bio.Ne.C.), "Sezione di Fisiologia umana G. Pagano", University of Palermo, Corso Tukory 129-90134 Palermo, Italy.
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31
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Aghazadeh Tabrizi M, Baraldi PG, Baraldi S, Gessi S, Merighi S, Borea PA. Medicinal Chemistry, Pharmacology, and Clinical Implications of TRPV1 Receptor Antagonists. Med Res Rev 2016; 37:936-983. [PMID: 27976413 DOI: 10.1002/med.21427] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 10/24/2016] [Accepted: 11/01/2016] [Indexed: 12/28/2022]
Abstract
Transient receptor potential vanilloid 1 (TRPV1) is an ion channel expressed on sensory neurons triggering an influx of cations. TRPV1 receptors function as homotetramers responsive to heat, proinflammatory substances, lipoxygenase products, resiniferatoxin, endocannabinoids, protons, and peptide toxins. Its phosphorylation increases sensitivity to both chemical and thermal stimuli, while desensitization involves a calcium-dependent mechanism resulting in receptor dephosphorylation. TRPV1 functions as a sensor of noxious stimuli and may represent a target to avoid pain and injury. TRPV1 activation has been associated to chronic inflammatory pain and peripheral neuropathy. Its expression is also detected in nonneuronal areas such as bladder, lungs, and cochlea where TRPV1 activation is responsible for pathology development of cystitis, asthma, and hearing loss. This review offers a comprehensive overview about TRPV1 receptor in the pathophysiology of chronic pain, epilepsy, cough, bladder disorders, diabetes, obesity, and hearing loss, highlighting how drug development targeting this channel could have a clinical therapeutic potential. Furthermore, it summarizes the advances of medicinal chemistry research leading to the identification of highly selective TRPV1 antagonists and their analysis of structure-activity relationships (SARs) focusing on new strategies to target this channel.
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Affiliation(s)
- Mojgan Aghazadeh Tabrizi
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, 44121, Ferrara, Italy
| | - Pier Giovanni Baraldi
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, 44121, Ferrara, Italy
| | - Stefania Baraldi
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, 44121, Ferrara, Italy
| | - Stefania Gessi
- Section of Pharmacology, Department of Medical Sciences, University of Ferrara, 44121, Ferrara, Italy
| | - Stefania Merighi
- Section of Pharmacology, Department of Medical Sciences, University of Ferrara, 44121, Ferrara, Italy
| | - Pier Andrea Borea
- Section of Pharmacology, Department of Medical Sciences, University of Ferrara, 44121, Ferrara, Italy
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32
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Rohleder C, Müller JK, Lange B, Leweke FM. Cannabidiol as a Potential New Type of an Antipsychotic. A Critical Review of the Evidence. Front Pharmacol 2016; 7:422. [PMID: 27877130 PMCID: PMC5099166 DOI: 10.3389/fphar.2016.00422] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 10/24/2016] [Indexed: 11/25/2022] Open
Abstract
There is urgent need for the development of mechanistically different and less side-effect prone antipsychotic compounds. The endocannabinoid system has been suggested to represent a potential new target in this indication. While the chronic use of cannabis itself has been considered a risk factor contributing to the development of schizophrenia, triggered by the phytocannabinoid delta-9-tetrahydrocannabinol (Δ9-THC), cannabidiol, the second most important phytocannabinoid, appears to have no psychotomimetic potential. Although, results from animal studies are inconsistent to a certain extent and seem to depend on behavioral paradigms, treatment duration and experimental conditions applied, cannabidiol has shown antipsychotic properties in both rodents and rhesus monkeys. After some individual treatment attempts, the first randomized, double-blind controlled clinical trial demonstrated that in acute schizophrenia cannabidiol exerts antipsychotic properties comparable to the antipsychotic drug amisulpride while being accompanied by a superior, placebo-like side effect profile. As the clinical improvement by cannabidiol was significantly associated with elevated anandamide levels, it appears likely that its antipsychotic action is based on mechanisms associated with increased anandamide concentrations. Although, a plethora of mechanisms of action has been suggested, their potential relevance for the antipsychotic effects of cannabidiol still needs to be investigated. The clarification of these mechanisms as well as the establishment of cannabidiol’s antipsychotic efficacy and its hopefully benign side-effect profile remains the subject of a number of previously started clinical trials.
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Affiliation(s)
- Cathrin Rohleder
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim Germany
| | - Juliane K Müller
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim Germany
| | - Bettina Lange
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim Germany
| | - F M Leweke
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim Germany
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33
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Postnatal Excitability Development and Innervation by Functional Transient Receptor Potential Vanilloid 1 (TRPV1) Terminals in Neurons of the Rat Spinal Sacral Dorsal Commissural Nucleus: an Electrophysiological Study. Mol Neurobiol 2016; 53:6033-6042. [PMID: 26526845 DOI: 10.1007/s12035-015-9510-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Accepted: 10/22/2015] [Indexed: 12/20/2022]
Abstract
The sacral dorsal commissural nucleus (SDCN) in the spinal cord receives both somatic and visceral primary afferents. Transient receptor potential vanilloid 1 (TRPV1) channels are preferentially expressed in certain fine primary afferents. However, knowledge of the SDCN neurons postnatal excitability development and their contacts with TRPV1 fibers remains elusive. Here, whole-cell recordings were conducted in spinal cord slices to evaluate the postnatal development of SDCN neurons and their possible contacts with functional TRPV1-expressing terminals. SDCN neurons in neonatal (postnatal day (P) 1-2), young (P8-10), and adult rats (P35-40) have different electrophysiological properties. SDCN neurons in neonatal rats have higher frequency of spontaneous firing, higher resting membrane potential, and lower presynaptic glutamate release probability. However, no difference in quantal release was found. At all developmental stages, TRPV1 activation with the selective agonist capsaicin increases glutamate release in the presence of tetrodotoxin, which blocks action potential-dependent and polysynaptic neurotransmission, indicating that functional TRPV1 fibers innervate SDCN neurons directly. Capsaicin-induced presynaptic glutamate release onto SDCN neurons depends on external Ca2+ influx through TRPV1 channels; voltage-dependent calcium channels had a slighter impact. In contrast, capsaicin blocked C fiber-evoked synaptic transmission, indicating that TRPV1 activation has opposite effects on spontaneous asynchronous and action potential-dependent synchronous glutamate release. These data indicate that excitability of SDCN neurons undergoes a developmental shift, and these neurons receive functional TRPV1 terminals from early postnatal stage. The opposite action of capsaicin on asynchronous and synchronous glutamate release should be taken into account when TRPV1 channels are considered as therapeutic targets.
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Abstract
Epilepsy has 2-3% incidence worldwide. However, present antiepileptic drugs provide only partial control of seizures. Calcium ion accumulation in hippocampal neurons has long been known as a major contributor to the etiology of epilepsy. TRPV1 is a calcium-permeable channel and mediator of epilepsy in the hippocampus. TRPV1 is expressed in epileptic brain areas such as CA1 area and dentate gyrus of the hippocampus. Here the author reviews the patent literature on novel molecules targeting TRPV1 that are currently being investigated in the laboratory and are candidates for future clinical evaluation in the management of epilepsy. A limited number of recent reports have implicated TRPV1 in the induction or treatment of epilepsy suggesting that this may be new area for potential drugs targeting this debilitating disease. Thus activation of TRPV1 by oxidative stress, resiniferatoxin, cannabinoid receptor (CB1) activators (i.e. anandamide) or capsaicin induced epileptic effects, and these effects could be reduced by appropriate inhibitors, including capsazepine (CPZ), 5'-iodoresiniferatoxin (IRTX), resolvins, and CB1 antagonists. It has been also reported that CPZ and IRTX reduced spontaneous excitatory synaptic transmission through modulation of glutaminergic systems and desensitization of TRPV1 channels in the hippocampus of rats. Immunocytochemical studies indicated that TRPV1 channel expression increased in the hippocampus of mice and patients with temporal lobe epilepsy. Taken together, findings in the current literature support a role for calcium ion accumulation through TRPV1 channels in the etiology of epileptic seizures, indicating that inhibition of TRPV1 in the hippocampus may possibly be a novel target for prevention of epileptic seizures.
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Affiliation(s)
- Mustafa Nazıroğlu
- Director of Neuroscience Research Center, Suleyman Demirel University, TR-32260, Isparta, Turkey.
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Abstract
Psychiatric and neurological disorders are mostly associated with the changes in neural calcium ion signaling pathways required for activity-triggered cellular events. One calcium channel family is the TRP cation channel family, which contains seven subfamilies. Results of recent papers have discovered that calcium ion influx through TRP channels is important. We discuss the latest advances in calcium ion influx through TRP channels in the etiology of psychiatric disorders. Activation of TRPC4, TRPC5, and TRPV1 cation channels in the etiology of psychiatric disorders such as anxiety, fear-associated responses, and depression modulate calcium ion influx. Evidence substantiates that anandamide and its analog (methanandamide) induce an anxiolytic-like effect via CB1 receptors and TRPV1 channels. Intracellular calcium influx induced by oxidative stress has an significant role in the etiology of bipolar disorders (BDs), and studies recently reported the important role of TRP channels such as TRPC3, TRPM2, and TRPV1 in converting oxidant or nitrogen radical signaling to cytosolic calcium ion homeostasis in BDs. The TRPV1 channel also plays a function in morphine tolerance and hyperalgesia. Among psychotropic drugs, amitriptyline and capsazepine seem to have protective effects on psychiatric disorders via the TRP channels. Some drugs such as cocaine and methamphetamine also seem to have an important role in alcohol addiction and substance abuse via activation of the TRPV1 channel. Thus, we explore the relationships between the etiology of psychiatric disorders and TRP channel-regulated mechanisms. Investigation of the TRP channels in psychiatric disorders holds the promise of the development of new drug treatments.
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Affiliation(s)
- Mustafa Nazıroğlu
- Neuroscience Research Center, Süleyman Demirel University, Dekanlık Binası, TR-32260, Isparta, Turkey.
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Abstract
Central neural circuits orchestrate the behavioral and autonomic repertoire that maintains body temperature during environmental temperature challenges and alters body temperature during the inflammatory response and behavioral states and in response to declining energy homeostasis. This review summarizes the central nervous system circuit mechanisms controlling the principal thermoeffectors for body temperature regulation: cutaneous vasoconstriction regulating heat loss and shivering and brown adipose tissue for thermogenesis. The activation of these thermoeffectors is regulated by parallel but distinct efferent pathways within the central nervous system that share a common peripheral thermal sensory input. The model for the neural circuit mechanism underlying central thermoregulatory control provides a useful platform for further understanding of the functional organization of central thermoregulation, for elucidating the hypothalamic circuitry and neurotransmitters involved in body temperature regulation, and for the discovery of novel therapeutic approaches to modulating body temperature and energy homeostasis.
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Affiliation(s)
- Shaun F Morrison
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR, USA
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37
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Therapeutic Potential of Cannabinoids in Psychosis. Biol Psychiatry 2016; 79:604-12. [PMID: 26852073 DOI: 10.1016/j.biopsych.2015.11.018] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 11/24/2015] [Accepted: 11/24/2015] [Indexed: 11/22/2022]
Abstract
Over recent years, the interest in the endocannabinoid system (ECS) as a new target for the treatment of schizophrenia has evolved. The ECS represents one of the most relevant neurotransmitter systems in the brain and mainly fulfills a homeostatic role in terms of neurotransmission but also with respect to inflammatory processes. Two main approaches to the modulation of endocannabinoid functioning have been chosen so far. First, the selective blockade or inverse agonism of the type 1 cannabinoid receptor has been tested for the improvement of acute psychotic symptoms, as well as for the improvement of cognitive functions in schizophrenia. This was not effective in either case. Second, the modulation of endocannabinoid levels by use of the phytocannabinoid cannabidiol and selective fatty acid amide hydrolase inhibitors has been proposed, and the antipsychotic properties of cannabidiol are currently being investigated in humans. Unfortunately, for most of these trials that have focused on psychopathological and cognitive effects of cannabidiol, no published data are available. However, there is first evidence that cannabidiol may ameliorate psychotic symptoms with a superior side-effect profile compared with established antipsychotics. In conclusion, several clinical trials targeting the ECS in acute schizophrenia have either been completed or are underway. Although publicly available results are currently limited, preliminary data indicate that selected compounds modulating the ECS may be effective in acute schizophrenia. Nevertheless, so far, sample sizes of patients investigated are not sufficient to come to a final judgment, and no maintenance studies are available to ensure long-term efficacy and safety.
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Yan L, Pan M, Fu M, Wang J, Huang W, Qian H. Design, synthesis and biological evaluation of novel analgesic agents targeting both cyclooxygenase and TRPV1. Bioorg Med Chem 2016; 24:849-57. [PMID: 26795113 DOI: 10.1016/j.bmc.2016.01.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Revised: 01/06/2016] [Accepted: 01/06/2016] [Indexed: 01/08/2023]
Abstract
Multitarget-directed ligands might offer certain advantages over traditional single-target drugs and/or drug combinations. In the present study, a series of novel analgesic agents targeting both cyclooxygenase and TRPV1 were prepared and evaluated in an effort to optimize properties of previously described lead compounds from piperazine, ethanediamine cores. These compounds were evaluated for antagonism of hTRPV1 activation by capsaicin and the ability to inhibit Ovine COX-1 and human recombinant COX-2 in vitro. The favorable potentials of these test compounds were further characterized in preliminary analgesic and side-effects tests in vivo. On the basis of comprehensive evaluations, compound 8d which showed strong TRPV1 antagonistic activity, middle COX-2 inhibition, weak ulcerogenic action and had no hyperthermia side-effect was considered as a safe candidate for the further development of analgesic drugs.
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Affiliation(s)
- Lin Yan
- Institute of Chemistry & Biology, Henan University, Kaifeng 475004, China
| | - Miaobo Pan
- State Key Laboratory of Natural Medicines, Center of Drug Discovery, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China
| | - Mian Fu
- State Key Laboratory of Natural Medicines, Center of Drug Discovery, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China
| | - Jingjie Wang
- State Key Laboratory of Natural Medicines, Center of Drug Discovery, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China; WuXiAppTec (Wuhan) Co., Ltd, Wuhan 430000, China
| | - Wenlong Huang
- State Key Laboratory of Natural Medicines, Center of Drug Discovery, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China.
| | - Hai Qian
- State Key Laboratory of Natural Medicines, Center of Drug Discovery, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China.
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Redmond WJ, Cawston EE, Grimsey NL, Stuart J, Edington AR, Glass M, Connor M. Identification of N-arachidonoyl dopamine as a highly biased ligand at cannabinoid CB1 receptors. Br J Pharmacol 2016; 173:115-27. [PMID: 26398720 PMCID: PMC4813372 DOI: 10.1111/bph.13341] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Revised: 09/13/2015] [Accepted: 09/17/2015] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND AND PURPOSE N-arachidonyl dopamine (NADA) has been identified as a putative endocannabinoid, but there is little information about which signalling pathways it activates. The purpose of this study was to identify the signalling pathways activated by NADA in vitro. EXPERIMENTAL APPROACH Human or rat cannabinoid CB1 receptors were expressed in AtT20, CHO or HEK 293 cells. NADA displacement of radiolabelled cannabinoids, and CB1 receptor mediated activation of K channels or ERK phosphorylation, release of intracellular calcium ([Ca]i ) and modulation of adenylyl cyclase were measured in addition to NADA effects on CB1 receptor trafficking. KEY RESULTS At concentrations up to 30 μM, NADA failed to activate any signalling pathways via CB1 receptors, with the exception of mobilization of [Ca]i . The elevations of [Ca]i were insensitive to pertussis toxin, and reduced or abolished by blockers of Gq /11 -dependent processes including U73122, thapsigargin and a peptide antagonist of Gq /11 activation. Prolonged NADA incubation produced modest loss of cell surface CB1 receptors. The prototypical cannabinoid agonist CP55940 signalled as expected in all assays. CONCLUSIONS AND IMPLICATIONS NADA is an ineffective agonist at most canonical cannabinoid receptor signalling pathways, but did promote mobilization of [Ca]i via Gq -dependent processes and some CB1 receptor trafficking. This signalling profile is distinct from that of any known cannabinoid, and suggests that NADA may have a unique spectrum of effects in vivo. Our results also indicate that it may be possible to identify highly biased CB1 receptor ligands displaying a subset of the pharmacological or therapeutic effects usually attributed to CB1 ligands.
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Affiliation(s)
- William J. Redmond
- Department of Biomedical Sciences, Faculty of Medicine and Health SciencesMacquarie UniversityNSW2109Australia
| | - Erin E. Cawston
- Department of Pharmacology and Clinical Pharmacology, and Centre for Brain ResearchUniversity of AucklandAucklandNew Zealand
| | - Natasha L. Grimsey
- Department of Pharmacology and Clinical Pharmacology, and Centre for Brain ResearchUniversity of AucklandAucklandNew Zealand
| | - Jordyn Stuart
- Department of Biomedical Sciences, Faculty of Medicine and Health SciencesMacquarie UniversityNSW2109Australia
| | - Amelia R. Edington
- Department of Biomedical Sciences, Faculty of Medicine and Health SciencesMacquarie UniversityNSW2109Australia
| | - Michelle Glass
- Department of Pharmacology and Clinical Pharmacology, and Centre for Brain ResearchUniversity of AucklandAucklandNew Zealand
| | - Mark Connor
- Department of Biomedical Sciences, Faculty of Medicine and Health SciencesMacquarie UniversityNSW2109Australia
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Matott MP, Ruyle BC, Hasser EM, Kline DD. Excitatory amino acid transporters tonically restrain nTS synaptic and neuronal activity to modulate cardiorespiratory function. J Neurophysiol 2015; 115:1691-702. [PMID: 26719090 DOI: 10.1152/jn.01054.2015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 12/24/2015] [Indexed: 11/22/2022] Open
Abstract
The nucleus tractus solitarii (nTS) is the initial central termination site for visceral afferents and is important for modulation and integration of multiple reflexes including cardiorespiratory reflexes. Glutamate is the primary excitatory neurotransmitter in the nTS and is removed from the extracellular milieu by excitatory amino acid transporters (EAATs). The goal of this study was to elucidate the role of EAATs in the nTS on basal synaptic and neuronal function and cardiorespiratory regulation. The majority of glutamate clearance in the central nervous system is believed to be mediated by astrocytic EAAT 1 and 2. We confirmed the presence of EAAT 1 and 2 within the nTS and their colocalization with astrocytic markers. EAAT blockade withdl-threo-β-benzyloxyaspartic acid (TBOA) produced a concentration-related depolarization, increased spontaneous excitatory postsynaptic current (EPSC) frequency, and enhanced action potential discharge in nTS neurons. Solitary tract-evoked EPSCs were significantly reduced by EAAT blockade. Microinjection of TBOA into the nTS of anesthetized rats induced apneic, sympathoinhibitory, depressor, and bradycardic responses. These effects mimicked the response to microinjection of exogenous glutamate, and glutamate responses were enhanced by EAAT blockade. Together these data indicate that EAATs tonically restrain nTS excitability to modulate cardiorespiratory function.
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Affiliation(s)
- Michael P Matott
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
| | - Brian C Ruyle
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
| | - Eileen M Hasser
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri; and Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
| | - David D Kline
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
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41
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Hermes SM, Andresen MC, Aicher SA. Localization of TRPV1 and P2X3 in unmyelinated and myelinated vagal afferents in the rat. J Chem Neuroanat 2015; 72:1-7. [PMID: 26706222 DOI: 10.1016/j.jchemneu.2015.12.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 11/18/2015] [Accepted: 12/09/2015] [Indexed: 01/15/2023]
Abstract
The vagus nerve is dominated by afferent fibers that convey sensory information from the viscera to the brain. Most vagal afferents are unmyelinated, slow-conducting C-fibers, while a smaller portion are myelinated, fast-conducting A-fibers. Vagal afferents terminate in the nucleus tractus solitarius (NTS) in the dorsal brainstem and regulate autonomic and respiratory reflexes, as well as ascending pathways throughout the brain. Vagal afferents form glutamatergic excitatory synapses with postsynaptic NTS neurons that are modulated by a variety of channels. The organization of vagal afferents with regard to fiber type and channels is not well understood. In the present study, we used tract tracing methods to identify distinct populations of vagal afferents to determine if key channels are selectively localized to specific groups of afferent fibers. Vagal afferents were labeled with isolectin B4 (IB4) or cholera toxin B (CTb) to detect unmyelinated and myelinated afferents, respectively. We find that TRPV1 channels are preferentially found in unmyelinated vagal afferents identified with IB4, with almost half of all IB4 fibers showing co-localization with TRPV1. These results agree with prior electrophysiological findings. In contrast, we found that the ATP-sensitive channel P2X3 is found in a subset of both myelinated and unmyelinated vagal afferent fibers. Specifically, 18% of IB4 and 23% of CTb afferents contained P2X3. The majority of CTb-ir vagal afferents contained neither channel. Since neither channel was found in all vagal afferents, there are likely further degrees of heterogeneity in the modulation of vagal afferent sensory input to the NTS beyond fiber type.
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Affiliation(s)
- Sam M Hermes
- Oregon Health & Science University, Department of Physiology and Pharmacology, 3181 Sam Jackson Park Road, Mailcode: L334, Portland, OR 97239-3098, United States
| | - Michael C Andresen
- Oregon Health & Science University, Department of Physiology and Pharmacology, 3181 Sam Jackson Park Road, Mailcode: L334, Portland, OR 97239-3098, United States
| | - Sue A Aicher
- Oregon Health & Science University, Department of Physiology and Pharmacology, 3181 Sam Jackson Park Road, Mailcode: L334, Portland, OR 97239-3098, United States.
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42
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Crawford DC, Kavalali ET. Molecular underpinnings of synaptic vesicle pool heterogeneity. Traffic 2015; 16:338-64. [PMID: 25620674 DOI: 10.1111/tra.12262] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 01/06/2015] [Indexed: 12/31/2022]
Abstract
Neuronal communication relies on chemical synaptic transmission for information transfer and processing. Chemical neurotransmission is initiated by synaptic vesicle fusion with the presynaptic active zone resulting in release of neurotransmitters. Classical models have assumed that all synaptic vesicles within a synapse have the same potential to fuse under different functional contexts. In this model, functional differences among synaptic vesicle populations are ascribed to their spatial distribution in the synapse with respect to the active zone. Emerging evidence suggests, however, that synaptic vesicles are not a homogenous population of organelles, and they possess intrinsic molecular differences and differential interaction partners. Recent studies have reported a diverse array of synaptic molecules that selectively regulate synaptic vesicles' ability to fuse synchronously and asynchronously in response to action potentials or spontaneously irrespective of action potentials. Here we discuss these molecular mediators of vesicle pool heterogeneity that are found on the synaptic vesicle membrane, on the presynaptic plasma membrane, or within the cytosol and consider some of the functional consequences of this diversity. This emerging molecular framework presents novel avenues to probe synaptic function and uncover how synaptic vesicle pools impact neuronal signaling.
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Affiliation(s)
- Devon C Crawford
- Department of Neuroscience, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9111, USA
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43
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Mizutani Y, Ohi Y, Kimura S, Miyazawa K, Goto S, Haji A. Effects of prostaglandin E2 on synaptic transmission in the rat spinal trigeminal subnucleus caudalis. Brain Res 2015; 1625:29-38. [PMID: 26320551 DOI: 10.1016/j.brainres.2015.08.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 07/16/2015] [Accepted: 08/20/2015] [Indexed: 11/26/2022]
Abstract
The spinal trigeminal subnucleus caudalis (Vc) receives preferentially nociceptive afferent signals from the orofacial area. Nociceptive stimuli to the orofacial area induce cyclooxygenase both peripherally and centrally, which can synthesize a major prostanoid prostaglandin E2 (PGE2) that implicates in diverse physiological functions. To clarify the roles of centrally-synthesized PGE2 in nociception, effects of exogenous PGE2 on synaptic transmission in the Vc neurons were investigated in the rat brainstem slice. Spontaneously occurring excitatory and inhibitory postsynaptic currents (sEPSCs and sIPSCs) were recorded, respectively, under pharmacological blockade of inhibitory and excitatory transmission by whole-cell patch-clamp mode. Perfusion of PGE2 (1-5 μM) increased the frequency of sIPSCs in a concentration-dependent manner but had no significant effect on the amplitude. Similarly to the effects on sIPSCs, PGE2 increased the sEPSC frequency without any effect on the amplitude. These facilitatory effects of PGE2 on spontaneous synaptic transmissions were blocked by an EP1 antagonist SC19220 but not by an EP4 antagonist AH23848. Electrical stimulation of the trigeminal tract evoked short latency EPSCs (eEPSCs) in the Vc neurons. PGE2 (5 μM) was ineffective on the eEPSCs. The present study demonstrated that PGE2 facilitated spontaneous synaptic transmissions in the Vc neurons through activating the presynaptic EP1 receptors but had no effect on the trigeminal tract-mediated excitatory transmission. These results suggest that centrally-synthesized PGE2 modifies the synaptic transmission in the Vc region, thereby contributing to the processing of nociceptive signals originated from the orofacial area.
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Affiliation(s)
- Yuka Mizutani
- Laboratory of Neuropharmacology, School of Pharmacy, Aichi Gakuin University, Nagoya 464-8650, Japan; Department of Orthodontics, School of Dentistry, Aichi Gakuin University, Nagoya 464-8650, Japan.
| | - Yoshiaki Ohi
- Laboratory of Neuropharmacology, School of Pharmacy, Aichi Gakuin University, Nagoya 464-8650, Japan.
| | - Satoko Kimura
- Laboratory of Neuropharmacology, School of Pharmacy, Aichi Gakuin University, Nagoya 464-8650, Japan.
| | - Ken Miyazawa
- Department of Orthodontics, School of Dentistry, Aichi Gakuin University, Nagoya 464-8650, Japan.
| | - Shigemi Goto
- Department of Orthodontics, School of Dentistry, Aichi Gakuin University, Nagoya 464-8650, Japan.
| | - Akira Haji
- Laboratory of Neuropharmacology, School of Pharmacy, Aichi Gakuin University, Nagoya 464-8650, Japan.
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Hofmann ME, Andresen MC. Vanilloids selectively sensitize thermal glutamate release from TRPV1 expressing solitary tract afferents. Neuropharmacology 2015; 101:401-11. [PMID: 26471418 DOI: 10.1016/j.neuropharm.2015.10.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 09/11/2015] [Accepted: 10/07/2015] [Indexed: 01/09/2023]
Abstract
Vanilloids, high temperature, and low pH activate the transient receptor potential vanilloid type 1 (TRPV1) receptor. In spinal dorsal root ganglia, co-activation of one of these gating sites on TRPV1 sensitized receptor gating by other modes. Here in rat brainstem slices, we examined glutamate synaptic transmission in nucleus of the solitary tract (NTS) neurons where most cranial primary afferents express TRPV1, but TRPV1 sensitization is unknown. Electrical shocks to the solitary tract (ST) evoked EPSCs (ST-EPSCs). Activation of TRPV1 with capsaicin (100 nM) increased spontaneous EPSCs (sEPSCs) but inhibited ST-EPSCs. High concentrations of the ultra-potent vanilloid resiniferatoxin (RTX, 1 nM) similarly increased sEPSC rates but blocked ST-EPSCs. Lowering the RTX concentration to 150 pM modestly increased the frequency of the sEPSCs without causing failures in the evoked ST-EPSCs. The sEPSC rate increased with raising bath temperature to 36 °C. Such thermal responses were larger in 150 pM RTX, while the ST-EPSCs remained unaffected. Vanilloid sensitization of thermal responses persisted in TTX but was blocked by the TRPV1 antagonist capsazepine. Our results demonstrate that multimodal activation of TRPV1 facilitates sEPSC responses in more than the arithmetic sum of the two activators, i.e. co-activation sensitizes TRPV1 control of spontaneous glutamate release. Since action potential evoked glutamate release is unaltered, the work provides evidence for cooperativity in gating TRPV1 plus a remarkable separation of calcium mechanisms governing the independent vesicle pools responsible for spontaneous and evoked release at primary afferents in the NTS.
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Affiliation(s)
- Mackenzie E Hofmann
- Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, OR, USA.
| | - Michael C Andresen
- Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, OR, USA
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45
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Fawley JA, Hofmann ME, Largent-Milnes TM, Andresen MC. Temperature differentially facilitates spontaneous but not evoked glutamate release from cranial visceral primary afferents. PLoS One 2015; 10:e0127764. [PMID: 25992717 PMCID: PMC4439140 DOI: 10.1371/journal.pone.0127764] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 04/20/2015] [Indexed: 11/19/2022] Open
Abstract
Temperature is fundamentally important to all biological functions including synaptic glutamate release. Vagal afferents from the solitary tract (ST) synapse on second order neurons in the nucleus of the solitary tract, and glutamate release at this first central synapse controls autonomic reflex function. Expression of the temperature-sensitive Transient Receptor Potential Vanilloid Type 1 receptor separates ST afferents into C-fibers (TRPV1+) and A-fibers (TRPV1-). Action potential-evoked glutamate release is similar between C- and A-fiber afferents, but TRPV1 expression facilitates a second form of synaptic glutamate release in C-fibers by promoting substantially more spontaneous glutamate release. The influence of temperature on different forms of glutamate release is not well understood. Here we tested how temperature impacts the generation of evoked and spontaneous release of glutamate and its relation to TRPV1 expression. In horizontal brainstem slices of rats, activation of ST primary afferents generated synchronous evoked glutamate release (ST-eEPSCs) at constant latency whose amplitude reflects the probability of evoked glutamate release. The frequency of spontaneous EPSCs in these same neurons measured the probability of spontaneous glutamate release. We measured both forms of glutamate from each neuron during ramp changes in bath temperature of 4-5 °C. Spontaneous glutamate release from TRPV1+ closely tracked with these thermal changes indicating changes in the probability of spontaneous glutamate release. In the same neurons, temperature changed axon conduction registered as latency shifts but ST-eEPSC amplitudes were constant and independent of TRPV1 expression. These data indicate that TRPV1-operated glutamate release is independent of action potential-evoked glutamate release in the same neurons. Together, these support the hypothesis that evoked and spontaneous glutamate release originate from two pools of vesicles that are independently modulated and are distinct processes.
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Affiliation(s)
- Jessica A. Fawley
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon, United States of America
- * E-mail:
| | - Mackenzie E. Hofmann
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Tally M. Largent-Milnes
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Michael C. Andresen
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon, United States of America
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46
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Abstract
Fast synaptic communication in the brain requires synchronous vesicle fusion that is evoked by action potential-induced Ca(2+) influx. However, synaptic terminals also release neurotransmitters by spontaneous vesicle fusion, which is independent of presynaptic action potentials. A functional role for spontaneous neurotransmitter release events in the regulation of synaptic plasticity and homeostasis, as well as the regulation of certain behaviours, has been reported. In addition, there is evidence that the presynaptic mechanisms underlying spontaneous release of neurotransmitters and their postsynaptic targets are segregated from those of evoked neurotransmission. These findings challenge current assumptions about neuronal signalling and neurotransmission, as they indicate that spontaneous neurotransmission has an autonomous role in interneuronal communication that is distinct from that of evoked release.
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47
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Makwana R, Venkatasamy R, Spina D, Page C. The Effect of Phytocannabinoids on Airway Hyper-Responsiveness, Airway Inflammation, and Cough. J Pharmacol Exp Ther 2015; 353:169-80. [DOI: 10.1124/jpet.114.221283] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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48
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Ohi Y, Kimura S, Haji A. Modulation of glutamatergic transmission by presynaptic N-methyl-d-aspartate mechanisms in second-order neurons of the rat nucleus tractus solitarius. Neurosci Lett 2015; 587:62-7. [DOI: 10.1016/j.neulet.2014.12.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 12/02/2014] [Accepted: 12/12/2014] [Indexed: 01/15/2023]
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49
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Xu H, Boychuk JA, Boychuk CR, Uteshev VV, Smith BN. Nicotine enhances inhibition of mouse vagal motor neurons by modulating excitability of premotor GABAergic neurons in the nucleus tractus solitarii. J Neurophysiol 2014; 113:1165-74. [PMID: 25429117 DOI: 10.1152/jn.00614.2014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The caudal nucleus of the solitary tract (NTS) serves as the site of the first synapse for visceral sensory inputs to the central nervous system. The NTS sends functional projections to multiple brain nuclei, with gastric-related projections primarily targeting the dorsal motor nucleus of the vagus (DMV). Previous studies have demonstrated that the majority of caudal NTS neurons that project to the DMV respond robustly to nicotine and express nicotinic acetylcholine receptors (nAChRs). However, the cytochemical identity and relationship with specific viscera of DMV-projecting, nicotine-responsive caudal NTS neurons have not been determined. The present study used transgenic mice that express enhanced green fluorescent protein (EGFP) under a GAD67 promoter in a subset of GABAergic neurons, in vivo retrograde pseudorabies viral labeling to identify gastric-related vagal complex neurons, and patch-clamp electrophysiology in acute brain stem slices to test the hypothesis that gastric-related and GABAergic inhibitory synaptic input to the DMV from the caudal NTS is under a robust modulatory control by nAChRs. Our results suggest that activation of nAChRs in the caudal NTS, but not DMV, potentiates GABAergic, but not glutamatergic, input to the DMV. Gastric-related caudal NTS and DMV neurons are directly involved in this nicotine-sensitive circuitry. Understanding the central patterns of nicotinic modulation of visceral sensory-motor circuitry may help develop therapeutic interventions to restore autonomic homeostasis in patients with autonomic impairments.
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Affiliation(s)
- Hong Xu
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky; and
| | - Jeffery A Boychuk
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky; and
| | - Carie R Boychuk
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky; and
| | - Victor V Uteshev
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas
| | - Bret N Smith
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky; and
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Soni N, Satpathy S, Kohlmeier KA. Neurophysiological evidence for the presence of cannabinoid CB1 receptors in the laterodorsal tegmental nucleus. Eur J Neurosci 2014; 40:3635-52. [PMID: 25251035 DOI: 10.1111/ejn.12730] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 08/13/2014] [Accepted: 08/20/2014] [Indexed: 12/31/2022]
Abstract
Marijuana, which acts within the endocannabinoid (eCB) system as an agonist of the cannabinoid type 1 receptor (CB1R), exhibits addictive properties and has powerful actions on the state of arousal of an organism. The laterodorsal tegmental nucleus (LDT), as a component of the reticular activating system, is involved in cortical activation and is important in the development of drug addiction-associated behaviours. Therefore, eCBs might exert behavioural effects by actions on the LDT; however, it is unknown whether eCBs have actions on neurons in this nucleus. Accordingly, whole-cell voltage- and current-clamp recordings were conducted from mouse brain slices, and responses of LDT neurons to the CB1R agonist WIN-2 were monitored. Our results showed that WIN-2 decreased the frequency of spontaneous and miniature inhibitory postsynaptic currents (sIPSCs and mIPSCs). Ongoing activity of endogenous eCBs was confirmed as AM251, a potent CB1R antagonist, elicited sIPSCs. WIN-2 reduced the firing frequency of LDT neurons. In addition, our RT-PCR studies confirmed the presence of CB1R transcript in the LDT. Taken together, we conclude that CB1Rs are functionally active in the LDT, and their activation changes the firing frequency and synaptic activity of neurons in this nucleus. Therefore, endogenous eCB transmission could play a role in processes involving the LDT, such as cortical activation and motivated behaviours and, further, behavioural actions of marijuana are probably mediated, in part, via cellular actions within the LDT induced by this addictive and behavioural state-altering drug.
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Affiliation(s)
- Neeraj Soni
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100, Copenhagen, Denmark
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