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Francis-Oliveira J, Higa GSV, Viana FJC, Cruvinel E, Carlos-Lima E, da Silva Borges F, Zampieri TT, Rebello FP, Ulrich H, De Pasquale R. TREK-1 inhibition promotes synaptic plasticity in the prelimbic cortex. Exp Neurol 2024; 373:114652. [PMID: 38103709 DOI: 10.1016/j.expneurol.2023.114652] [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: 10/06/2023] [Revised: 11/28/2023] [Accepted: 12/10/2023] [Indexed: 12/19/2023]
Abstract
Synaptic plasticity is one of the putative mechanisms involved in the maturation of the prefrontal cortex (PFC) during postnatal development. Early life stress (ELS) affects the shaping of cortical circuitries through impairment of synaptic plasticity supporting the onset of mood disorders. Growing evidence suggests that dysfunctional postnatal maturation of the prelimbic division (PL) of the PFC might be related to the emergence of depression. The potassium channel TREK-1 has attracted particular interest among many factors that modulate plasticity, concerning synaptic modifications that could underlie mood disorders. Studies have found that ablation of TREK-1 increases the resilience to depression, while rats exposed to ELS exhibit higher TREK-1 levels in the PL. TREK-1 is regulated by multiple intracellular transduction pathways including the ones activated by metabotropic receptors. In the hippocampal neurons, TREK-1 interacts with the serotonergic system, one of the main factors involved in the action of antidepressants. To investigate possible mechanisms related to the antidepressant role of TREK-1, we used brain slice electrophysiology to evaluate the effects of TREK-1 pharmacological blockade on synaptic plasticity at PL circuitry. We extended this investigation to animals subjected to ELS. Our findings suggest that in non-stressed animals, TREK-1 activity is required for the reduction of synaptic responses mediated by the 5HT1A receptor activation. Furthermore, we demonstrate that TREK-1 blockade promotes activity-dependent long-term depression (LTD) when acting in synergy with 5HT1A receptor stimulation. On the other hand, in ELS animals, TREK-1 blockade reduces synaptic transmission and facilitates LTD expression. These results indicate that TREK-1 inhibition stimulates synaptic plasticity in the PL and this effect is more pronounced in animals subjected to ELS during postnatal development.
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Affiliation(s)
- José Francis-Oliveira
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, SP 05508-000, Brazil; Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Guilherme Shigueto Vilar Higa
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, SP 05508-000, Brazil; Departamento de Bioquímica, Instituto de Química (USP), Butantã, SP 05508-900, Brazil; Laboratório de Neurogenética, Universidade Federal do ABC, São Bernardo do Campo, SP 09210-580, Brazil
| | - Felipe José Costa Viana
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, SP 05508-000, Brazil
| | - Emily Cruvinel
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, SP 05508-000, Brazil
| | - Estevão Carlos-Lima
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, SP 05508-000, Brazil
| | - Fernando da Silva Borges
- Department of Physiology & Pharmacology, SUNY Downstate Health Sciences University, Brooklyn, NY 11203, USA
| | - Thais Tessari Zampieri
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, SP 05508-000, Brazil
| | - Fernanda Pereira Rebello
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, SP 05508-000, Brazil
| | - Henning Ulrich
- Departamento de Bioquímica, Instituto de Química (USP), Butantã, SP 05508-900, Brazil
| | - Roberto De Pasquale
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, SP 05508-000, Brazil.
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2
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Soares-Cunha C, Heinsbroek JA. Ventral pallidal regulation of motivated behaviors and reinforcement. Front Neural Circuits 2023; 17:1086053. [PMID: 36817646 PMCID: PMC9932340 DOI: 10.3389/fncir.2023.1086053] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 01/06/2023] [Indexed: 02/05/2023] Open
Abstract
The interconnected nuclei of the ventral basal ganglia have long been identified as key regulators of motivated behavior, and dysfunction of this circuit is strongly implicated in mood and substance use disorders. The ventral pallidum (VP) is a central node of the ventral basal ganglia, and recent studies have revealed complex VP cellular heterogeneity and cell- and circuit-specific regulation of reward, aversion, motivation, and drug-seeking behaviors. Although the VP is canonically considered a relay and output structure for this circuit, emerging data indicate that the VP is a central hub in an extensive network for reward processing and the regulation of motivation that extends beyond classically defined basal ganglia borders. VP neurons respond temporally faster and show more advanced reward coding and prediction error processing than neurons in the upstream nucleus accumbens, and regulate the activity of the ventral mesencephalon dopamine system. This review will summarize recent findings in the literature and provide an update on the complex cellular heterogeneity and cell- and circuit-specific regulation of motivated behaviors and reinforcement by the VP with a specific focus on mood and substance use disorders. In addition, we will discuss mechanisms by which stress and drug exposure alter the functioning of the VP and produce susceptibility to neuropsychiatric disorders. Lastly, we will outline unanswered questions and identify future directions for studies necessary to further clarify the central role of VP neurons in the regulation of motivated behaviors. Significance: Research in the last decade has revealed a complex cell- and circuit-specific role for the VP in reward processing and the regulation of motivated behaviors. Novel insights obtained using cell- and circuit-specific interrogation strategies have led to a major shift in our understanding of this region. Here, we provide a comprehensive review of the VP in which we integrate novel findings with the existing literature and highlight the emerging role of the VP as a linchpin of the neural systems that regulate motivation, reward, and aversion. In addition, we discuss the dysfunction of the VP in animal models of neuropsychiatric disorders.
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Affiliation(s)
- Carina Soares-Cunha
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B’s-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Jasper A. Heinsbroek
- Department of Anesthesiology, University of Colorado, Anschutz Medical Campus, Aurora, CO, United States
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Ji MJ, Gao ZQ, Yang J, Cai JH, Li KX, Wang J, Zhang H, Zhou CH, Cao JL, Liu C. Dynorphin promotes stress-induced depressive behaviors by inhibiting ventral pallidal neurons in rats. Acta Physiol (Oxf) 2022; 236:e13882. [PMID: 36039689 DOI: 10.1111/apha.13882] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 08/24/2022] [Accepted: 08/26/2022] [Indexed: 01/29/2023]
Abstract
AIM Endogenous dynorphin signaling via kappa opioid receptors (KORs) plays a key role in producing the depressive and aversive consequences of stress. We investigated the behavioral effects of the dynorphin/KOR system in the ventral pallidum (VP) and studied the underlying mechanisms. METHODS To investigate the effects of dynorphin on the VP, we conducted behavioral experiments after microinjection of drugs or shRNA and brain-slice electrophysiological recordings. Histological tracing and molecular biological experiments were used to identify the distribution of KORs and the possible sources of dynorphin projections to the VP. RESULTS An elevated dynorphin concentration and increased KOR activity were observed in the VP after acute stress. Infusion of dynorphin-A into the VP produced depressive-like phenotypes including anhedonia and despair and anxiety behaviors, but did not alter locomotor behavior. Mechanistically, dynorphin had an inhibitory effect on VP neurons-reducing their firing rate and inhibiting excitatory transmission-through direct activation of KORs and modulation of downstream G-protein-gated inwardly rectifying potassium (GIRK) channels and high-voltage gated calcium channels (VGCCs). Tracing revealed direct innervation of VP neurons by dynorphin-positive projections; potential sources of these dynorphinergic projections include the nucleus accumbens, amygdala, and hypothalamus. Blockade of dynorphin/KOR signaling in the VP by drugs or viral knock-down of KORs significantly reduced despair behavior in rats. CONCLUSIONS Endogenous dynorphinergic modulation of the VP plays a critical role in mediating depressive reactions to stress.
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Affiliation(s)
- Miao-Jin Ji
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, China
| | - Zhi-Qiang Gao
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Jiao Yang
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, China
| | - Ji-Heng Cai
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, China
| | - Ke-Xue Li
- Department of Physiology, Xuzhou Medical University, Xuzhou, China
| | - Jie Wang
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, China
| | - Hongxing Zhang
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, China
| | - Cheng-Hua Zhou
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Jun-Li Cao
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, China
| | - Chao Liu
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, China
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Nishijo T, Suzuki E, Momiyama T. Serotonin 5‐HT
1A
and 5‐HT
1B
receptor‐mediated inhibition of glutamatergic transmission onto rat basal forebrain cholinergic neurones. J Physiol 2022; 600:3149-3167. [DOI: 10.1113/jp282509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 05/18/2022] [Indexed: 11/08/2022] Open
Affiliation(s)
- Takuma Nishijo
- Department of Pharmacology Jikei University School of Medicine 3‐25‐8 Nishi‐Shimbashi, Minato‐ku Tokyo 105–8461 Japan
- Department of Molecular Neurobiology Institute for Developmental Research Aichi Developmental Disability Center, 713–8 Kamiya Kasugai Aichi 480‐0392 Japan
| | - Etsuko Suzuki
- Department of Pharmacology Jikei University School of Medicine 3‐25‐8 Nishi‐Shimbashi, Minato‐ku Tokyo 105–8461 Japan
| | - Toshihiko Momiyama
- Department of Pharmacology Jikei University School of Medicine 3‐25‐8 Nishi‐Shimbashi, Minato‐ku Tokyo 105–8461 Japan
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Grossman CD, Bari BA, Cohen JY. Serotonin neurons modulate learning rate through uncertainty. Curr Biol 2022; 32:586-599.e7. [PMID: 34936883 PMCID: PMC8825708 DOI: 10.1016/j.cub.2021.12.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 10/11/2021] [Accepted: 12/03/2021] [Indexed: 12/20/2022]
Abstract
Regulating how fast to learn is critical for flexible behavior. Learning about the consequences of actions should be slow in stable environments, but accelerate when that environment changes. Recognizing stability and detecting change are difficult in environments with noisy relationships between actions and outcomes. Under these conditions, theories propose that uncertainty can be used to modulate learning rates ("meta-learning"). We show that mice behaving in a dynamic foraging task exhibit choice behavior that varied as a function of two forms of uncertainty estimated from a meta-learning model. The activity of dorsal raphe serotonin neurons tracked both types of uncertainty in the foraging task as well as in a dynamic Pavlovian task. Reversible inhibition of serotonin neurons in the foraging task reproduced changes in learning predicted by a simulated lesion of meta-learning in the model. We thus provide a quantitative link between serotonin neuron activity, learning, and decision making.
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Affiliation(s)
- Cooper D Grossman
- The Solomon H. Snyder Department of Neuroscience, Brain Science Institute, Kavli Neuroscience Discovery Institute, The Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205, USA
| | - Bilal A Bari
- The Solomon H. Snyder Department of Neuroscience, Brain Science Institute, Kavli Neuroscience Discovery Institute, The Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205, USA
| | - Jeremiah Y Cohen
- The Solomon H. Snyder Department of Neuroscience, Brain Science Institute, Kavli Neuroscience Discovery Institute, The Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205, USA.
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Kupchik YM, Prasad AA. Ventral pallidum cellular and pathway specificity in drug seeking. Neurosci Biobehav Rev 2021; 131:373-386. [PMID: 34562544 DOI: 10.1016/j.neubiorev.2021.09.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 09/03/2021] [Accepted: 09/05/2021] [Indexed: 01/12/2023]
Abstract
The ventral pallidum (VP) is central to the reinforcing effects across a variety of drugs and relapse to drug seeking. Emerging studies from animal models of reinstatement reveal a complex neurobiology of the VP that contributes to different aspects of relapse to drug seeking. This review builds on classical understanding of the VP as part of the final common pathway of relapse but also discusses the properties of the VP as an independent structure. These include VP neural anatomical subregions, cellular heterogeneity, circuitry, neurotransmitters and peptides. Collectively, this review provides a current understanding of the VP from molecular to circuit level architecture that contributes to both the appetitive and aversive symptoms of drug addiction. We show the complex neurobiology of the VP in drug seeking, emphasizing its critical role in addiction, and review strategic approaches that target the VP to reduce relapse rates.
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Affiliation(s)
- Yonatan M Kupchik
- Faculty of Medicine, The Hebrew University of Jerusalem, Ein Kerem. P.O. Box 12271, Jerusalem, 9112102, Israel
| | - Asheeta A Prasad
- School of Psychology, UNSW Sydney, NSW, 2052, Australia; Faculty of Medicine and Health, University of Sydney, NSW 2006, Australia.
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7
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Clark M. Effects of Electrical Stimulation of NAc Afferents on VP Neurons' Tonic Firing. Front Cell Neurosci 2020; 14:599920. [PMID: 33328895 PMCID: PMC7719775 DOI: 10.3389/fncel.2020.599920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 11/03/2020] [Indexed: 11/16/2022] Open
Abstract
Afferents from the nucleus accumbens (NAc) are a major source of input into the ventral pallidum (VP). Research reveals that these afferents are GABAergic, however, stimulation of these afferents induces both excitatory and inhibitory responses within the VP. These are likely to be partially mediated by enkephalin and substance P (SP), which are also released by these afferents, and are known to modulate VP neurons. However, less is known about the potentially differential effects stimulation of these afferents has on subpopulations of neurons within the VP and the cellular mechanisms by which they exert their effects. The current study aimed to research this further using brain slices containing the VP, stimulation of the NAc afferents, and multi-electrode array (MEA) recordings of their VP targets. Stimulation of the NAc afferents induced a pause in the tonic firing in 58% of the neurons studied in the VP, while 42% were not affected. Measures used to reveal the electrophysiological difference between these groups found no significant differences in firing frequency, coefficient of variation, and spike half-width. There were however significant differences in the pause duration between neurons in the dorsal and ventral VP, with stimulation of NAc afferents producing a significantly longer pause (0.48 ± 0.06 s) in tonic firing in dorsal VP neurons, compared to neurons in the ventral VP (0.21 ± 0.09 s). Pauses in the tonic firing of VP neurons, as a result of NAc afferent stimulation, were found to be largely mediated by GABAA receptors, as the application of picrotoxin significantly reduced their duration. Opioid agonists and antagonists were found to have no significant effects on the pause in tonic activity induced by NAc afferent stimulation. However, NK-1 receptor antagonists caused significant decreases in the pause duration, suggesting that SP may contribute to the inhibitory effect of NAc afferent stimulation via activation of NK-1 receptors.
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Affiliation(s)
- Martin Clark
- Department of Psychology, The University of Central Lancashire, Preston, United Kingdom
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8
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Thirumaran SL, Lepailleur A, Rochais C. Structure-activity relationships of serotonin 5-HT7 receptors ligands: A review. Eur J Med Chem 2019; 183:111705. [DOI: 10.1016/j.ejmech.2019.111705] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 09/13/2019] [Accepted: 09/14/2019] [Indexed: 01/30/2023]
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9
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Ji MJ, Zhang XY, Chen Z, Wang JJ, Zhu JN. Orexin prevents depressive-like behavior by promoting stress resilience. Mol Psychiatry 2019; 24:282-293. [PMID: 30087452 PMCID: PMC6755988 DOI: 10.1038/s41380-018-0127-0] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 04/17/2018] [Accepted: 06/20/2018] [Indexed: 12/21/2022]
Abstract
Hypothalamic neuropeptide orexin has been implicated in the pathophysiology of psychiatric disorders and accumulating clinical evidence indicates a potential link between orexin and depression. However, the exact role of orexin in depression, particularly the underlying neural substrates and mechanisms, remains unknown. In this study, we reveal a direct projection from the hypothalamic orexinergic neurons to the ventral pallidum (VP), a structure that receives an increasing attention for its critical position in rewarding processing, stress responses, and depression. We find that orexin directly excites GABAergic VP neurons and prevents depressive-like behaviors in rats. Two orexin receptors, OX1R and OX2R, and their downstream Na+-Ca2+ exchanger and L-type Ca2+ channel co-mediate the effect of orexin. Furthermore, pharmacological blockade or genetic knockdown of orexin receptors in VP increases depressive-like behaviors in forced swim test and sucrose preference test. Intriguingly, blockage of orexinergic inputs in VP has no impact on social proximity in social interaction test between novel partners, but remarkably strengthens social avoidance under an acute psychosocial stress triggered by social rank. Notably, a significantly increased orexin level in VP is accompanied by an increase in serum corticosterone in animals exposed to acute stresses, including forced swimming, food/water deprivation and social rank stress, rather than non-stress situations. These results suggest that endogenous orexinergic modulation on VP is especially critical for protecting against depressive reactions to stressful events. The findings define an indispensable role for the central orexinergic system in preventing depression by promoting stress resilience.
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Affiliation(s)
- Miao-Jin Ji
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Physiology, School of Life Sciences, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China
| | - Xiao-Yang Zhang
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Physiology, School of Life Sciences, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China
| | - Zi Chen
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Physiology, School of Life Sciences, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China
| | - Jian-Jun Wang
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Physiology, School of Life Sciences, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China.
- Institute for Brain Sciences, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China.
| | - Jing-Ning Zhu
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Physiology, School of Life Sciences, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China.
- Institute for Brain Sciences, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China.
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Clark M, Bracci E. Dichotomous Dopaminergic Control of Ventral Pallidum Neurons. Front Cell Neurosci 2018; 12:260. [PMID: 30186117 PMCID: PMC6113373 DOI: 10.3389/fncel.2018.00260] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 07/30/2018] [Indexed: 01/14/2023] Open
Abstract
The ventral pallidum (VP) is crucially involved in reward processing. Dopaminergic afferents reach the VP from the ventral tegmental area (VTA). Recent in vivo studies suggest dopamine application increase the firing in the VP. However, little is known about the cellular effects of dopamine within the VP. We aimed to address this paucity of data using brain slices containing the VP and multi-electrode array recordings. Dopamine significantly affected firing in 86% of spontaneously active VP neurons. Among the affected neurons, 84% were excited, while 16% were inhibited. The selective D1-like receptor agonist SKF81297 also had modulatory effects on the majority of VP neurons, but its effects were universally excitatory. On the other hand, the D2-like receptor agonist quinpirole had modulatory effects on 87% of VP neurons studied. It caused significant inhibitory effects in 33% of the cases and excitatory effects in the remaining 67%. The effects of D1-like receptor activation were presynaptic as blocking synaptic transmission with low Ca2+ abolished the effects of SKF81297 application. Furthermore, SKF81297 effects were abolished by blocking ionotropic glutamate receptors, suggesting that D1-like receptors boost glutamate release, which in turn excites VP neurons through postsynaptic glutamate receptors. Effects caused by D2-like receptor activation were found to involve pre and postsynaptic mechanisms, as low Ca2+ abolished the excitatory effects of quinpirole but not the inhibitory ones. Increases in firing frequency (ff) to quinpirole application were abolished by a group 2/3 mGluR antagonist, suggesting that D2-like receptors cause presynaptic inhibition of glutamate release, resulting in reduced postsynaptic activation of inhibitory mGluRs. Conversely, the inhibitory effects of quinpirole persisted in low Ca2+ and therefore can be attributed to postsynaptic D2-like receptor activation. VP neurons excited by dopamine had shorter spike half-widths and are excited by D1-like receptors (presynaptically) and by D2-like receptors (postsynaptically). VP neurons inhibited by dopamine have longer spike half-widths and while D1-like receptor activation has a presynaptic excitatory influence on them, D2-like receptor activation has a postsynaptic inhibitory effect that prevails, on balance. These data provide novel insights into the cellular mechanisms by which dopamine controls information processing within the VP.
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Affiliation(s)
- Martin Clark
- Department of Psychology, The University of Sheffield, Sheffield, United Kingdom
| | - Enrico Bracci
- Department of Psychology, The University of Sheffield, Sheffield, United Kingdom
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11
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Tooley J, Marconi L, Alipio JB, Matikainen-Ankney B, Georgiou P, Kravitz AV, Creed MC. Glutamatergic Ventral Pallidal Neurons Modulate Activity of the Habenula-Tegmental Circuitry and Constrain Reward Seeking. Biol Psychiatry 2018; 83:1012-1023. [PMID: 29452828 PMCID: PMC5972062 DOI: 10.1016/j.biopsych.2018.01.003] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 01/02/2018] [Accepted: 01/04/2018] [Indexed: 12/29/2022]
Abstract
BACKGROUND The ability to appropriately integrate and respond to rewarding and aversive stimuli is essential for survival. The ventral pallidum (VP) plays a critical role in processing both rewarding and aversive stimuli. However, the VP is a heterogeneous structure, and how VP subpopulations integrate into larger reward networks to ultimately modulate these behaviors is not known. We identify a noncanonical population of glutamatergic VP neurons that play a unique role in responding to aversive stimuli and constraining inappropriate reward seeking. METHODS Using neurochemical, genetic, and electrophysiological approaches, we characterized glutamatergic VP neurons (n = 4-8 mice/group). We performed patch clamp and in vivo electrophysiology recordings in the lateral habenula, rostromedial tegmental nucleus, and ventral tegmental area to determine the effect of glutamatergic VP neuron activation in these target regions (n = 6-10 mice/group). Finally, we selectively optogenetically stimulated glutamatergic VP neurons in a real-time place preference task and ablated these neurons using a virally expressed caspase to determine their necessity for reward seeking. RESULTS Glutamatergic VP neurons exhibit little overlap with cholinergic or gamma-aminobutyric acidergic markers, the canonical VP subtypes, and exhibit distinct membrane properties. Glutamatergic VP neurons innervate and increase firing activity of the lateral habenula, rostromedial tegmental nucleus, and gamma-aminobutyric acidergic ventral tegmental area neurons. While nonselective optogenetic stimulation of the VP induced a robust place preference, selective activation of glutamatergic VP neurons induced a place avoidance. Viral ablation of glutamatergic VP neurons increased reward responding and abolished taste aversion to sucrose. CONCLUSIONS Glutamatergic VP neurons constitute a noncanonical subpopulation of VP neurons. These glutamatergic VP neurons increase activity of the lateral habenula, rostromedial tegmental nucleus, and gamma-aminobutyric acidergic ventral tegmental area neurons and adaptively constrain reward seeking.
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Affiliation(s)
- Jessica Tooley
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Lauren Marconi
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Jason Bondoc Alipio
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Bridget Matikainen-Ankney
- Eating and Addiction Section, National Institute of Digestive and Diabetes and Kidney Diseases, Bethesda, Maryland
| | - Polymnia Georgiou
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland
| | - Alexxai V Kravitz
- Eating and Addiction Section, National Institute of Digestive and Diabetes and Kidney Diseases, Bethesda, Maryland
| | - Meaghan C Creed
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, Maryland.
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12
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Mahoney EC, Zeng A, Yu W, Rowe M, Sahai S, Feustel PJ, Ramirez-Zamora A, Pilitsis JG, Shin DS. Ventral pallidum deep brain stimulation attenuates acute partial, generalized and tonic-clonic seizures in two rat models. Epilepsy Res 2018; 142:36-44. [DOI: 10.1016/j.eplepsyres.2018.03.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 02/17/2018] [Accepted: 03/08/2018] [Indexed: 11/29/2022]
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13
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Nishijo T, Momiyama T. Serotonin 5-HT1Breceptor-mediated calcium influx-independent presynaptic inhibition of GABA release onto rat basal forebrain cholinergic neurons. Eur J Neurosci 2016; 44:1747-60. [DOI: 10.1111/ejn.13273] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 04/06/2016] [Accepted: 04/11/2016] [Indexed: 12/13/2022]
Affiliation(s)
- Takuma Nishijo
- Department of Pharmacology; Jikei University School of Medicine; Nishi-Shimbashi, Minato-ku Tokyo 105-8461 Japan
| | - Toshihiko Momiyama
- Department of Pharmacology; Jikei University School of Medicine; Nishi-Shimbashi, Minato-ku Tokyo 105-8461 Japan
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Optogenetic Activation of Dorsal Raphe Serotonin Neurons Rapidly Inhibits Spontaneous But Not Odor-Evoked Activity in Olfactory Cortex. J Neurosci 2016; 36:7-18. [PMID: 26740645 DOI: 10.1523/jneurosci.3008-15.2016] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
UNLABELLED Serotonin (5-hydroxytriptamine; 5-HT) is implicated in a variety of brain functions including not only the regulation of mood and control of behavior but also the modulation of perception. 5-HT neurons in the dorsal raphe nucleus (DRN) often fire locked to sensory stimuli, but little is known about how 5-HT affects sensory processing, especially on this timescale. Here, we used an optogenetic approach to study the effect of 5-HT on single-unit activity in the mouse primary olfactory (anterior piriform) cortex. We show that activation of DRN 5-HT neurons rapidly inhibits the spontaneous firing of olfactory cortical neurons, acting in a divisive manner, but entirely spares sensory-driven firing. These results identify a new role for serotonergic modulation in dynamically regulating the balance between different sources of neural activity in sensory systems, suggesting a possible role for 5-HT in perceptual inference. SIGNIFICANCE STATEMENT Serotonin is implicated in a wide variety of (pato)physiological functions including perception, but its precise role has remained elusive. Here, using optogenetic tools in vivo, we show that serotonergic neuromodulation prominently inhibits the spontaneous electrical activity of neurons in the primary olfactory cortex on a rapid (<1 s) timescale but leaves sensory responses unaffected. These results identify a new role for serotonergic modulation in rapidly changing the balance between different sources of neural activity in sensory systems.
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Deep Brain Stimulation of the Ventral Pallidum Attenuates Epileptiform Activity and Seizing Behavior in Pilocarpine-Treated Rats. Brain Stimul 2015; 9:285-95. [PMID: 26723019 DOI: 10.1016/j.brs.2015.11.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Revised: 10/30/2015] [Accepted: 11/16/2015] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Brain stimulation is effective for people with intractable epilepsy. However, modulating neural targets that provide greater efficacy to more individuals is still needed. OBJECTIVE/HYPOTHESIS We investigate whether bilateral deep brain stimulation of the ventral pallidum (VP-DBS) has potent seizure control in pilocarpine-treated rats. METHODS VP-DBS (50 Hz) was applied prior to generalized forebrain seizures or after generalized brainstem seizures manifested. Behavioral seizures were assessed using a modified Racine scale. In vitro and in vivo electrophysiological techniques were employed to identify how VP-DBS affects proximal and distal neuronal activity. The open field test was used to see if acute and chronic VP-DBS affected gross motor function or arousal state. Parametric and non-parametric statistics with post-hoc analysis were performed. RESULTS VP-DBS prior to pilocarpine prevented behavioral forebrain and brainstem seizures in most animals (n = 15). VP-DBS after brainstem seizures emerged prevented or reduced the appearance of subsequent behavioral brainstem seizures (n = 11). VP-DBS attenuated epileptiform activity in the hippocampus (n = 5), but not in the primary somatosensory cortex (S1) (n = 4) in vivo. Electrical stimulation in the VP increased VP GABAergic neuronal firing activity from 3.1 ± 1.4 Hz to 7.6 ± 1.7 Hz (n = 8) in vitro and reduced substantia nigra reticulata and superior colliculus neuronal spiking activity from 25.4 ± 3.3 Hz to 18.2 ± 1.4 Hz (n = 6) and 18.2 ± 1.4 Hz to 11.0 ± 1.1 Hz (n = 18), respectively, in vivo. CONCLUSION VP-DBS can be a novel and potent therapeutic approach for individuals with intractable epilepsy.
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Root DH, Melendez RI, Zaborszky L, Napier TC. The ventral pallidum: Subregion-specific functional anatomy and roles in motivated behaviors. Prog Neurobiol 2015; 130:29-70. [PMID: 25857550 PMCID: PMC4687907 DOI: 10.1016/j.pneurobio.2015.03.005] [Citation(s) in RCA: 229] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 03/19/2015] [Accepted: 03/29/2015] [Indexed: 12/17/2022]
Abstract
The ventral pallidum (VP) plays a critical role in the processing and execution of motivated behaviors. Yet this brain region is often overlooked in published discussions of the neurobiology of mental health (e.g., addiction, depression). This contributes to a gap in understanding the neurobiological mechanisms of psychiatric disorders. This review is presented to help bridge the gap by providing a resource for current knowledge of VP anatomy, projection patterns and subregional circuits, and how this organization relates to the function of VP neurons and ultimately behavior. For example, ventromedial (VPvm) and dorsolateral (VPdl) VP subregions receive projections from nucleus accumbens shell and core, respectively. Inhibitory GABAergic neurons of the VPvm project to mediodorsal thalamus, lateral hypothalamus, and ventral tegmental area, and this VP subregion helps discriminate the appropriate conditions to acquire natural rewards or drugs of abuse, consume preferred foods, and perform working memory tasks. GABAergic neurons of the VPdl project to subthalamic nucleus and substantia nigra pars reticulata, and this VP subregion is modulated by, and is necessary for, drug-seeking behavior. Additional circuits arise from nonGABAergic neuronal phenotypes that are likely to excite rather than inhibit their targets. These subregional and neuronal phenotypic circuits place the VP in a unique position to process motivationally relevant stimuli and coherent adaptive behaviors.
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Affiliation(s)
- David H Root
- Department of Psychology, Rutgers University, 152 Frelinghuysen Road, New Brunswick, NJ 08854, United States.
| | - Roberto I Melendez
- Department of Anatomy and Neurobiology, University of Puerto Rico School of Medicine, San Juan, PR 00936, United States.
| | - Laszlo Zaborszky
- Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, 197 University Avenue, Newark, NJ 07102, United States.
| | - T Celeste Napier
- Departments of Pharmacology and Psychiatry, Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL 60612, United States.
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Ciranna L, Catania MV. 5-HT7 receptors as modulators of neuronal excitability, synaptic transmission and plasticity: physiological role and possible implications in autism spectrum disorders. Front Cell Neurosci 2014; 8:250. [PMID: 25221471 PMCID: PMC4145633 DOI: 10.3389/fncel.2014.00250] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 08/06/2014] [Indexed: 12/22/2022] Open
Abstract
Serotonin type 7 receptors (5-HT7) are expressed in several brain areas, regulate brain development, synaptic transmission and plasticity, and therefore are involved in various brain functions such as learning and memory. A number of studies suggest that 5-HT7 receptors could be potential pharmacotherapeutic target for cognitive disorders. Several abnormalities of serotonergic system have been described in patients with autism spectrum disorder (ASD), including abnormal activity of 5-HT transporter, altered blood and brain 5-HT levels, reduced 5-HT synthesis and altered expression of 5-HT receptors in the brain. A specific role for 5-HT7 receptors in ASD has not yet been demonstrated but some evidence implicates their possible involvement. We have recently shown that 5-HT7 receptor activation rescues hippocampal synaptic plasticity in a mouse model of Fragile X Syndrome, a monogenic cause of autism. Several other studies have shown that 5-HT7 receptors modulate behavioral flexibility, exploratory behavior, mood disorders and epilepsy, which include core and co-morbid symptoms of ASD. These findings further suggest an involvement of 5-HT7 receptors in ASD. Here, we review the physiological roles of 5-HT7 receptors and their implications in Fragile X Syndrome and other ASD.
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Affiliation(s)
- Lucia Ciranna
- Department of Biomedical Sciences, University of Catania Catania, Italy
| | - Maria Vincenza Catania
- Institute of Neurological Sciences, the National Research Council of Italy (CNR) Catania, Italy ; Laboratory of Neurobiology, IRCCS Oasi Maria SS Troina, Italy
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18
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Miguelez C, Morera-Herreras T, Torrecilla M, Ruiz-Ortega JA, Ugedo L. Interaction between the 5-HT system and the basal ganglia: functional implication and therapeutic perspective in Parkinson's disease. Front Neural Circuits 2014; 8:21. [PMID: 24672433 PMCID: PMC3955837 DOI: 10.3389/fncir.2014.00021] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 02/27/2014] [Indexed: 01/15/2023] Open
Abstract
The neurotransmitter serotonin (5-HT) has a multifaceted function in the modulation of information processing through the activation of multiple receptor families, including G-protein-coupled receptor subtypes (5-HT1, 5-HT2, 5-HT4-7) and ligand-gated ion channels (5-HT3). The largest population of serotonergic neurons is located in the midbrain, specifically in the raphe nuclei. Although the medial and dorsal raphe nucleus (DRN) share common projecting areas, in the basal ganglia (BG) nuclei serotonergic innervations come mainly from the DRN. The BG are a highly organized network of subcortical nuclei composed of the striatum (caudate and putamen), subthalamic nucleus (STN), internal and external globus pallidus (or entopeduncular nucleus in rodents, GPi/EP and GPe) and substantia nigra (pars compacta, SNc, and pars reticulata, SNr). The BG are part of the cortico-BG-thalamic circuits, which play a role in many functions like motor control, emotion, and cognition and are critically involved in diseases such as Parkinson's disease (PD). This review provides an overview of serotonergic modulation of the BG at the functional level and a discussion of how this interaction may be relevant to treating PD and the motor complications induced by chronic treatment with L-DOPA.
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Affiliation(s)
- Cristina Miguelez
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of the Basque Country UPV/EHU Leioa, Spain ; Department of Pharmacology, Faculty of Pharmacy, University of the Basque Country UPV/EHU Vitoria-Gasteiz, Spain
| | - Teresa Morera-Herreras
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of the Basque Country UPV/EHU Leioa, Spain
| | - Maria Torrecilla
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of the Basque Country UPV/EHU Leioa, Spain
| | - Jose A Ruiz-Ortega
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of the Basque Country UPV/EHU Leioa, Spain ; Department of Pharmacology, Faculty of Pharmacy, University of the Basque Country UPV/EHU Vitoria-Gasteiz, Spain
| | - Luisa Ugedo
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of the Basque Country UPV/EHU Leioa, Spain
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19
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Multiple controls exerted by 5-HT2C receptors upon basal ganglia function: from physiology to pathophysiology. Exp Brain Res 2013; 230:477-511. [PMID: 23615975 DOI: 10.1007/s00221-013-3508-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 03/28/2013] [Indexed: 10/26/2022]
Abstract
Serotonin2C (5-HT2C) receptors are expressed in the basal ganglia, a group of subcortical structures involved in the control of motor behaviour, mood and cognition. These receptors are mediating the effects of 5-HT throughout different brain areas via projections originating from midbrain raphe nuclei. A growing interest has been focusing on the function of 5-HT2C receptors in the basal ganglia because they may be involved in various diseases of basal ganglia function notably those associated with chronic impairment of dopaminergic transmission. 5-HT2C receptors act on numerous types of neurons in the basal ganglia, including dopaminergic, GABAergic, glutamatergic or cholinergic cells. Perhaps inherent to their peculiar molecular properties, the modality of controls exerted by 5-HT2C receptors over these cell populations can be phasic, tonic (dependent on the 5-HT tone) or constitutive (a spontaneous activity without the presence of the ligand). These controls are functionally organized in the basal ganglia: they are mainly localized in the input structures and preferentially distributed in the limbic/associative territories of the basal ganglia. The nature of these controls is modified in neuropsychiatric conditions such as Parkinson's disease, tardive dyskinesia or addiction. Most of the available data indicate that the function of 5-HT2C receptor is enhanced in cases of chronic alterations of dopamine neurotransmission. The review illustrates that 5-HT2C receptors play a role in maintaining continuous controls over the basal ganglia via multiple diverse actions. We will discuss their interest for treatments aimed at ameliorating current pharmacotherapies in schizophrenia, Parkinson's disease or drugs abuse.
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20
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Kupchik YM, Kalivas PW. The rostral subcommissural ventral pallidum is a mix of ventral pallidal neurons and neurons from adjacent areas: an electrophysiological study. Brain Struct Funct 2012; 218:1487-500. [PMID: 23143342 DOI: 10.1007/s00429-012-0471-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Accepted: 10/25/2012] [Indexed: 12/29/2022]
Abstract
The ventral pallidum (VP) is a part of the ventral striatopallidal system and is involved in reward-related behaviors. The VP is composed of a ventromedial (VPvm) and a dorsolateral (VPdl) subregion, and some rostral-caudal differences are reported. Study of the VP often focuses on the subcommissural VP, typically considered homogenous in spite of known subdivisions. In this work, we used slice electrophysiology combined with immunohistochemistry for marker neuropeptides to test whether the subcommissural VP is functionally homogenous. Using sagittal slices, we show that more lateral levels (2.40 mm) of the subcommissural VP are homogenous but that a more medial slice (1.90 mm) contains two types of neurons. One type, located more caudally, resembles neurons in the lateral subcommissural VP, with long aspiny dendrites, primarily GABAergic input, and characteristic electrophysiological properties, such as depolarized membrane potential and spontaneous action potential discharge. The second type of neuron, located mostly in the rostral subcommissural VP, shows properties that are akin to medium spiny neurons of adjacent regions, including spiny dendrites, major glutamatergic input, hyperpolarized membrane potential, and no spontaneous action potentials. The two types of neurons were present in both the VPvm and VPdl, implying that the mix is not a characteristic of histologically defined subregions. We conclude that at medial levels the rostral subcommissural VP contains a mix of typical ventral pallidal neurons and spiny neurons similar to those in adjacent regions. This observation needs to be considered when interpreting past experiments and designing future experiments in the subcommissural VP.
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Affiliation(s)
- Yonatan M Kupchik
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC, 29425, USA,
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21
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Root DH, Fabbricatore AT, Pawlak AP, Barker DJ, Ma S, West MO. Slow phasic and tonic activity of ventral pallidal neurons during cocaine self-administration. Synapse 2011; 66:106-27. [PMID: 21953543 DOI: 10.1002/syn.20990] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Accepted: 09/14/2011] [Indexed: 02/06/2023]
Abstract
Ventral pallidal (VP) neurons exhibit rapid phasic firing patterns within seconds of cocaine-reinforced responses. The present investigation examined whether VP neurons exhibited firing rate changes: (1) over minutes during the inter-infusion interval (slow phasic patterns) and/or (2) over the course of the several-hour self-administration session (tonic firing patterns) relative to pre-session firing. Approximately three-quarters (43/54) of VP neurons exhibited slow phasic firing patterns. The most common pattern was a post-infusion decrease in firing followed by a progressive reversal of firing over minutes (51.16%; 22/43). Early reversals were predominantly observed anteriorly whereas progressive and late reversals were observed more posteriorly. Approximately half (51.85%; 28/54) of the neurons exhibited tonic firing patterns consisting of at least a two-fold change in firing. Most cells decreased firing during drug loading, remained low over self-administration maintenance, and reversed following lever removal. Over a whole experiment (tonic) timescale, the majority of neurons exhibited an inverse relationship between calculated drug level and firing rates during loading and post-self-administration behaviors. Fewer neurons exhibited an inverse relationship of calculated drug level and tonic firing rate during self-administration maintenance but, among those that did, nearly all were progressive reversal neurons. The present results show that, similar to its main afferent the nucleus accumbens, VP exhibits both slow phasic and tonic firing patterns during cocaine self-administration. Given that VP neurons are principally GABAergic, the predominant slow phasic decrease and tonic decrease firing patterns within the VP may indicate a disinhibitory influence upon its thalamocortical, mesolimbic, and nigrostriatal targets during cocaine self-administration.
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Affiliation(s)
- David H Root
- Department of Psychology, Rutgers University, New Brunswick, New Jersey 08903, USA
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De Deurwaerdère P, Mignon L, Chesselet MF. Physiological and Pathophysiological Aspects of 5-HT2c Receptors in Basal Ganglia. 5-HT2C RECEPTORS IN THE PATHOPHYSIOLOGY OF CNS DISEASE 2011. [DOI: 10.1007/978-1-60761-941-3_18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
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Leopoldo M, Lacivita E, Berardi F, Perrone R, Hedlund PB. Serotonin 5-HT7 receptor agents: Structure-activity relationships and potential therapeutic applications in central nervous system disorders. Pharmacol Ther 2010; 129:120-48. [PMID: 20923682 DOI: 10.1016/j.pharmthera.2010.08.013] [Citation(s) in RCA: 147] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Accepted: 08/26/2010] [Indexed: 12/19/2022]
Abstract
Since its discovery in the 1940s in serum, the mammalian intestinal mucosa, and in the central nervous system, serotonin (5-HT) has been shown to be involved in virtually all cognitive and behavioral human functions, and alterations in its neurochemistry have been implicated in the etiology of a plethora of neuropsychiatric disorders. The cloning of 5-HT receptor subtypes has been of importance in enabling them to be classified as specific protein molecules encoded by specific genes. The 5-HT(7) receptor is the most recently classified member of the serotonin receptor family. Since its identification, it has been the subject of intense research efforts driven by its presence in functionally relevant regions of the brain. The availability of some selective antagonists and agonists, in combination with genetically modified mice lacking the 5-HT(7) receptor, has allowed for a better understanding of the pathophysiological role of this receptor. This paper reviews data on localization and pharmacological properties of the 5-HT(7) receptor, and summarizes the results of structure-activity relationship studies aimed at the discovery of selective 5-HT(7) receptor ligands. Additionally, an overview of the potential therapeutic applications of 5-HT(7) receptor agonists and antagonists in central nervous system disorders is presented.
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Affiliation(s)
- Marcello Leopoldo
- Dipartimento Farmaco-Chimico, Università degli Studi di Bari "A. Moro", via Orabona, 4, 70125 Bari, Italy.
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Drago A, Serretti A. Focus on HTR2C: A possible suggestion for genetic studies of complex disorders. Am J Med Genet B Neuropsychiatr Genet 2009; 150B:601-37. [PMID: 18802918 DOI: 10.1002/ajmg.b.30864] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
HTR2C is one of the most relevant and investigated serotonin receptors. Its role in important brain structures such as the midbrain, the lateral septal complex, the hypothalamus, the olfactory bulb, the pons, the choroid plexus, the nucleus pallidus, the striatum and the amygdala, the nucleus accumbens and the anterior cingulated gyrus candidate it as a promising target for genetic association studies. The biological relevance of these brain structures is reviewed by way of the focus on HTR2C activity, with a special attention paid to psychiatric disorders. Evidence from the genetic association studies that dealt with HTR2C is reviewed and discussed alongside the findings derived from the neuronatmic investigations. The reasons for the discrepancies between these two sets of reports are discussed. As a result, HTR2C is shown to play a pivotal role in many different psychiatric behaviors or psychiatric related disrupted molecular balances, nevertheless, genetic association studies brought inconsistent results so far. The most replicated association involve the feeding behavior and antipsychotic induced side effects, both weight gain and motor related: Cys23Ser (rs6318) and -759C/T (rs3813929) report the most consistent results. The lack of association found in other independent studies dampens the clinical impact of these reports. Here, we report a possible explanation for discrepant findings that is poorly or not at all usually considered, that is that HTR2C may exert different or even opposite activities in the brain depending on the structure analyzed and that mRNA editing activity may compensate possible genetically controlled functional effects. The incomplete coverage of the HTR2C variants is proposed as the best cost-benefit ratio bias to fix. The evidence of brain area specific HTR2C mRNA editing opens a debate about how the brain can differently modulate stress events, and process antidepressant treatments, in different brain areas. The mRNA editing activity on HTR2C may play a major role for the negative association results.
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Affiliation(s)
- Antonio Drago
- Institute of Psychiatry, University of Bologna, Italy
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Hashimoto K, Kita H. Serotonin Activates Presynaptic and Postsynaptic Receptors in Rat Globus Pallidus. J Neurophysiol 2008; 99:1723-32. [DOI: 10.1152/jn.01143.2007] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although recent histological, behavioral, and clinical studies suggest that serotonin (5-HT) plays significant roles in the control of pallidal activity, only little is known about the physiological action of 5-HT in the pallidum. Our recent unit recording study in monkeys suggested that 5-HT provides both presynaptic and postsynaptic modulations of pallidal neurons. The present study using rat brain slice preparations further explored these presynaptic and postsynaptic actions of 5-HT. Bath application of 5-HT or the 5-HT1A/1B/1D/5/7 receptor (R) agonist 5-carboxamidotryptamine maleate (5-CT) depolarized some and hyperpolarized other pallidal neurons. Pretreatments of slices with blockers of the hyperpolarization–cyclic nucleotide-activated current or with the 5-HT2/7R–selective antagonist mesulergine occluded 5-CT–induced depolarization. The 5-HT1AR–selective blocker N-[2[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]- N-2-pyridinylcyclohex- anecarboxamide maleate occluded the 5-CT–induced hyperpolarization. These results suggested involvement of 5-HT7R and 5-HT1AR in the postsynaptic depolarization and hyperpolarization, respectively. 5-CT presynaptically suppressed both internal capsule stimulation–induced excitatory postsynaptic currents (EPSCs) and striatal stimulation–induced inhibitory postsynaptic currents (IPSCs). The potencies of 5-CT on the presynaptic effects were 20- to 25-fold higher than on postsynaptic effects, suggesting that 5-HT mainly modulates presynaptic sites in the globus pallidus. Experiments with several antagonists suggested involvement of 5-HT1B/DR in the presynaptic suppression of EPSCs. However, the receptor type involved in the presynaptic suppression of IPSCs was inconclusive. The present results provided evidence that 5-HT exerts significant control over the synaptic inputs and the autonomous activity of pallidal neurons.
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Chen L, Yung KKL, Chan YS, Yung WH. 5-HT excites globus pallidus neurons by multiple receptor mechanisms. Neuroscience 2007; 151:439-51. [PMID: 18082329 DOI: 10.1016/j.neuroscience.2007.11.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Revised: 10/31/2007] [Accepted: 11/30/2007] [Indexed: 11/26/2022]
Abstract
Anatomical and neurochemical studies indicated that the globus pallidus receives serotonergic innervation from raphe nuclei but the membrane effects of 5-HT on globus pallidus neurons are not entirely clear. We address this question by applying whole-cell patch-clamp recordings on globus pallidus neurons in immature rat brain slices. Under current-clamp recording, 5-HT depolarized globus pallidus neurons and increased their firing rate, an action blocked by both 5-HT(4) and 5-HT(7) receptor antagonists and attributable to an increase in cation conductance(s). Further experiments indicated that 5-HT enhanced the hyperpolarization-activated inward conductance which is blocked by 5-HT(7) receptor antagonist. To determine if 5-HT exerts any presynaptic effects on GABAergic and glutamatergic inputs, the actions of 5-HT on synaptic currents were studied. At 10 microM, 5-HT increased the frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) but had no effect on both the frequency and amplitude of miniature inhibitory postsynaptic currents (mIPSCs). However, 5-HT at a higher concentration (50 microM) decreased the frequency but not the amplitude of the mIPSCs, indicating an inhibition of GABA release from the presynaptic terminals. This effect was sensitive to 5-HT(1B) receptor antagonist. In addition to the presynaptic effects on GABAergic neurotransmission, 5-HT at 50 microM had no consistent effects on glutamatergic neurotransmission, significantly increased the frequency of miniature excitatory postsynaptic currents (mEPSCs) in 4 of 11 neurons and decreased the frequency of mEPSCs in 3 of 11 neurons. In conclusion, we found that 5-HT could modulate the excitability of globus pallidus neurons by both pre- and post-synaptic mechanisms. In view of the extensive innervation by globus pallidus neurons on other basal ganglia nuclei, this action of 5-HT originated from the raphe may have a profound effect on the operation of the entire basal ganglia network.
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Affiliation(s)
- L Chen
- Department of Physiology, The Chinese University of Hong Kong, Shatin, Hong Kong, China
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Kita H, Chiken S, Tachibana Y, Nambu A. Serotonin modulates pallidal neuronal activity in the awake monkey. J Neurosci 2007; 27:75-83. [PMID: 17202474 PMCID: PMC6672275 DOI: 10.1523/jneurosci.4058-06.2007] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Serotonin (5-HT)-containing neurons in the dorsal raphe project to the external and internal segments of the pallidum, which express several 5-HT receptors. Although the involvement of 5-HT in basal ganglia movement control has been suggested, little is known about the physiological action of 5-HT in the pallidum. Previous anatomical studies and in vitro physiological studies in other brain areas have suggested the following possibilities: (1) 5-HT suppresses GABAergic inhibition through presynaptic 5-HT1B receptors; (2) 5-HT decreases the firing of pallidal neurons through postsynaptic 5-HT1A receptors; and (3) 5-HT postsynaptically excites pallidal neurons through activation of 5-HT2C, 5-HT4, or 5-HT7 receptors. To test these possibilities, we examined the effects of locally applied agonists and antagonists of 5-HT on spontaneous neuronal firing and on excitatory and inhibitory responses of pallidal neurons to electrical stimulation of the motor cortex in awake monkeys. Although in vivo experiments could not conclusively determine the receptor types or the active sites involved in the observed effects, the results suggested the following possibilities: (1) 5-HT strongly suppresses GABAergic inhibition probably through 5-HT1B receptors; (2) in the external pallidal segment, the suppression may involve additional receptors or mechanisms; and (3) 5-HT suppresses glutamatergic excitation probably through 5-HT1A (and not 5-HT1B) receptors. The present study did not isolate or identify the existence of strong, direct postsynaptic inhibitory or excitatory effects of 5-HT. Thus, present results imply that 5-HT modulates synaptic inputs of both pallidal segments and exerts a significant role in movement control.
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Affiliation(s)
- Hitoshi Kita
- Department of Anatomy and Neurobiology, College of Medicine, University of Tennessee Memphis, Memphis, Tennessee 38163, USA.
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McDaid J, Tedford CE, Mackie AR, Dallimore JE, Mickiewicz AL, Shen F, Angle JM, Napier TC. Nullifying drug-induced sensitization: behavioral and electrophysiological evaluations of dopaminergic and serotonergic ligands in methamphetamine-sensitized rats. Drug Alcohol Depend 2007; 86:55-66. [PMID: 16762517 DOI: 10.1016/j.drugalcdep.2006.05.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2006] [Revised: 04/28/2006] [Accepted: 05/09/2006] [Indexed: 01/20/2023]
Abstract
Repeated exposure to methamphetamine produces a persistent enhancement of the acute motor effects of the drug, commonly referred to as behavioral sensitization. Behavioral sensitization involves monoaminergic projections to several forebrain nuclei. We recently revealed that the ventral pallidum (VP) may also be involved. In this study, we sought to establish if treatments with antagonists or partial agonists to monoaminergic receptors could "reverse" methamphetamine-induced behavioral and VP neuronal sensitization. Behavioral sensitization was obtained in rats with five once-daily s.c. injections of 2.5mg/kg methamphetamine, an effect that persisted for at least 60 days. After the development of sensitization, 15 once-daily treatments of mirtazapine (a 5-HT(2/3), alpha(2) and H(1) antagonist), SKF38393 (D(1) partial agonist) or SCH23390 (dopamine D(1) antagonist) nullified indices of motor sensitization as assessed by measuring the motoric response to an acute methamphetamine challenge 30 days after the fifth repeated methamphetamine treatment. VP neurons recorded in vivo from methamphetamine-sensitized rats at the 30-day withdrawal time also showed a robust downward shift in the excitatory responses observed to an acute i.v. methamphetamine challenge in non-sensitized rats. This decreased excitatory effect was reversed by mirtazapine, but not by other antagonists that were tested. These data suggest a potential therapeutic benefit for mirtazapine in the treatment of methamphetamine addiction, and point to a possible role for the VP in the sensitization process to methamphetamine.
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Affiliation(s)
- J McDaid
- Department of Pharmacology and Experimental Therapeutics, Loyola University Chicago Medical Center, 2160 South First Ave., Maywood, IL 60153-5515, USA
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Otmakhova NA, Lewey J, Asrican B, Lisman JE. Inhibition of perforant path input to the CA1 region by serotonin and noradrenaline. J Neurophysiol 2005; 94:1413-22. [PMID: 15888529 DOI: 10.1152/jn.00217.2005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Bath-applied monoamines-dopamine (DA), serotonin (5-HT), and noradrenaline (NE)-strongly suppress the perforant path (PP) input to CA1 hippocampal region with very little effect on the Schaffer collaterals (SC) input. The effect of DA action on PP field excitatory postsynaptic potential (fEPSP) has been characterized in detail, but relatively little is known about the NE and 5-HT effects. Here we show that the maximal inhibition of the PP fEPSP by NE is approximately 55%, whereas 5-HT inhibition is weaker ( approximately 35%). The half-maximal inhibitory concentration of both 5-HT and NE is approximately 1 muM. Neither NE nor 5-HT affected paired-pulse facilitation, suggesting that the effect is not presynaptic. This is in contrast to DA, which does have a presynaptic effect. The NE effect was blocked by alpha2 antagonists, whereas the alpha1 antagonist corynanthine and beta-antagonist propranolol were ineffective. The effect of 5-HT was mimicked by the agonist, 5-carboxamidotryptamine maleate (5-CT), and not affected by adrenergic and dopaminergic antagonists. To determine the 5-HT receptors involved, we tested a number of 5-HT antagonists, but none produced a complete suppression of the 5-HT effect. Of these, only the 5-HT7 and 5-HT2 antagonists produced weak but significant inhibition of 5-HT effect. We conclude that NE inhibits the PP fEPSP through postsynaptic action on alpha2-adrenoceptors and that 5-HT7, 5-HT2, and some other receptor may be involved in 5-HT action in PP.
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Affiliation(s)
- Nonna A Otmakhova
- Department of Biology and Volen Center for Complex Systems, Brandeis University, Waltham, MA 02454, USA
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Liu J, Jordan LM. Stimulation of the parapyramidal region of the neonatal rat brain stem produces locomotor-like activity involving spinal 5-HT7 and 5-HT2A receptors. J Neurophysiol 2005; 94:1392-404. [PMID: 15872068 DOI: 10.1152/jn.00136.2005] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Locomotion can be induced in rodents by direct application 5-hydroxytryptamine (5-HT) onto the spinal cord. Previous studies suggest important roles for 5-HT7 and 5-HT2A receptors in the locomotor effects of 5-HT. Here we show for the first time that activation of a discrete population of 5-HT neurons in the rodent brain stem produces locomotion and that the evoked locomotion requires 5-HT7 and 5-HT2A receptors. Cells localized in the parapyramidal region (PPR) of the mid-medulla produced locomotor-like activity as a result of either electrical or chemical stimulation, and PPR-evoked locomotor-like activity was blocked by antagonists to 5-HT2A and 5-HT7 receptors located on separate populations of neurons concentrated in different rostro-caudal regions. 5-HT7 receptor antagonists blocked locomotor-like activity when applied above the L3 segment; 5-HT2A receptor antagonists blocked locomotor-like activity only when applied below the L2 segment. 5-HT7 receptor antagonists decreased step cycle duration, consistent with an action on neurons involved in the rhythm-generating function of the central pattern generator (CPG) for locomotion. 5-HT2A antagonists reduced the amplitude of ventral root activity with only small effects on step cycle duration, suggesting an action directly on cells involved in the output stage of the pattern generator for locomotion, including motoneurons and premotor cells. Experiments with selective antagonists show that dopaminergic (D1, D2) and noradrenergic (alpha1, alpha2) receptors are not critical for PPR-evoked locomotor-like activity.
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Affiliation(s)
- Jun Liu
- Department of Physiology, Spinal Cord Research Centre, University of Manitoba Winnipeg, Winnipeg, Canada
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