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Muheyati A, Jiang S, Wang N, Yu G, Su R. Extrasynaptic GABA A receptors in central medial thalamus mediate anesthesia in rats. Eur J Pharmacol 2024; 972:176561. [PMID: 38580182 DOI: 10.1016/j.ejphar.2024.176561] [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: 10/11/2023] [Revised: 03/28/2024] [Accepted: 04/03/2024] [Indexed: 04/07/2024]
Abstract
Neuronal depression in the thalamus underlies anesthetic-induced loss of consciousness, while the precise sub-thalamus nuclei and molecular targets involved remain to be elucidated. The present study investigated the role of extrasynaptic GABAA receptors in the central medial thalamic nucleus (CM) in anesthesia induced by gaboxadol (THIP) and diazepam (DZP) in rats. Local lesion of the CM led to a decrease in the duration of loss of righting reflex induced by THIP and DZP. CM microinjection of THIP but not DZP induced anesthesia. The absence of righting reflex in THIP-treated rats was consistent with the increase of low frequency oscillations in the delta band in the medial prefrontal cortex. CM microinjection of GABAA receptor antagonist SR95531 significantly attenuated the anesthesia induced by systemically-administered THIP, but not DZP. Moreover, the rats with declined expression of GABAA receptor δ-subunit in the CM were less responsive to THIP or DZP. These findings explained a novel mechanism of THIP-induced loss of consciousness and highlighted the role of CM extrasynaptic GABAA receptors in mediating anesthesia.
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Affiliation(s)
- Alai Muheyati
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing, China
| | - Shanshan Jiang
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing, China
| | - Na Wang
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing, China
| | - Gang Yu
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing, China.
| | - Ruibin Su
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing, China.
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2
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Armijo-Weingart L, San Martin L, Gallegos S, Araya A, Konar-Nie M, Fernandez-Pérez E, Aguayo LG. Loss of glycine receptors in the nucleus accumbens and ethanol reward in an Alzheimer´s Disease mouse model. Prog Neurobiol 2024; 237:102616. [PMID: 38723884 PMCID: PMC11163974 DOI: 10.1016/j.pneurobio.2024.102616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 03/21/2024] [Accepted: 05/01/2024] [Indexed: 05/12/2024]
Abstract
Alterations in cognitive and non-cognitive cerebral functions characterize Alzheimer's disease (AD). Cortical and hippocampal impairments related to extracellular accumulation of Aβ in AD animal models have been extensively investigated. However, recent reports have also implicated intracellular Aβ in limbic regions, such as the nucleus accumbens (nAc). Accumbal neurons express high levels of inhibitory glycine receptors (GlyRs) that are allosterically modulated by ethanol and have a role in controlling its intake. In the present study, we investigated how GlyRs in the 2xTg mice (AD model) affect nAc functions and ethanol intake behavior. Using transgenic and control aged-matched litter mates, we found that the GlyRα2 subunit was significantly decreased in AD mice (6-month-old). We also examined intracellular calcium dynamics using the fluorescent calcium protein reporter GCaMP in slice photometry. We also found that the calcium signal mediated by GlyRs, but not GABAAR, was also reduced in AD neurons. Additionally, ethanol potentiation was significantly decreased in accumbal neurons in the AD mice. Finally, we performed drinking in the dark (DID) experiments and found that 2xTg mice consumed less ethanol on the last day of DID, in agreement with a lower blood ethanol concentration. 2xTg mice also showed lower sucrose consumption, indicating that overall food reward was altered. In conclusion, the data support the role of GlyRs in nAc neuron excitability and a decreased glycinergic activity in the 2xTg mice that might lead to impairment in reward processing at an early stage of the disease.
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Affiliation(s)
- Lorena Armijo-Weingart
- Laboratory of Neurophysiology, Department of Physiology, Universidad de Concepción, Chile; Programa de Neurociencia, Psiquiatría y Salud Mental (NEPSAM), Universidad de Concepción, Chile
| | - Loreto San Martin
- Laboratory of Neurophysiology, Department of Physiology, Universidad de Concepción, Chile; Programa de Neurociencia, Psiquiatría y Salud Mental (NEPSAM), Universidad de Concepción, Chile
| | - Scarlet Gallegos
- Laboratory of Neurophysiology, Department of Physiology, Universidad de Concepción, Chile
| | - Anibal Araya
- Laboratory of Neurophysiology, Department of Physiology, Universidad de Concepción, Chile
| | - Macarena Konar-Nie
- Laboratory of Neurophysiology, Department of Physiology, Universidad de Concepción, Chile
| | - Eduardo Fernandez-Pérez
- Laboratory of Neurophysiology, Department of Physiology, Universidad de Concepción, Chile; Programa de Neurociencia, Psiquiatría y Salud Mental (NEPSAM), Universidad de Concepción, Chile
| | - Luis G Aguayo
- Laboratory of Neurophysiology, Department of Physiology, Universidad de Concepción, Chile.
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3
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Mitchell SJ, Phillips GD, Tench B, Li Y, Belelli D, Martin SJ, Swinny JD, Kelly L, Atack JR, Paradowski M, Lambert JJ. Neurosteroid Modulation of Synaptic and Extrasynaptic GABA A Receptors of the Mouse Nucleus Accumbens. Biomolecules 2024; 14:460. [PMID: 38672476 PMCID: PMC11048561 DOI: 10.3390/biom14040460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 03/29/2024] [Accepted: 04/04/2024] [Indexed: 04/28/2024] Open
Abstract
The recent approval of formulations of the endogenous neurosteroid allopregnanolone (brexanolone) and the synthetic neuroactive steroid SAGE-217 (zuranolone) to treat postpartum depression (PPD) has encouraged further research to elucidate why these potent enhancers of GABAAR function are clinically effective in this condition. Dopaminergic projections from the ventral tegmental area (VTA) to the nucleus accumbens are associated with reward/motivation and brain imaging studies report that individuals with PPD show reduced activity of this pathway in response to reward and infant engagement. However, the influence of neurosteroids on GABA-ergic transmission in the nucleus accumbens has received limited attention. Here, we investigate, in the medium spiny neurons (MSNs) of the mouse nucleus accumbens core, the effect of allopregnanolone, SAGE-217 and other endogenous and synthetic steroids of interest on fast phasic and tonic inhibition mediated by synaptic (α1/2βγ2) and extrasynaptic (α4βδ) GABAARs, respectively. We present evidence suggesting the resident tonic current results from the spontaneous opening of δ-GABAARs, where the steroid-enhanced tonic current is GABA-dependent. Furthermore, we demonstrate local neurosteroid synthesis in the accumbal slice preparation and reveal that GABA-ergic neurotransmission of MSNs is influenced by an endogenous neurosteroid tone. Given the dramatic fluctuations in allopregnanolone levels during pregnancy and postpartum, this neurosteroid-mediated local fine-tuning of GABAergic transmission in the MSNs will probably be perturbed.
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Affiliation(s)
- Scott J. Mitchell
- Division of Cellular & Systems Medicine, School of Medicine, Medical Sciences Institute, Dundee University, Dow Street, Dundee DD1 5HL, UK; (S.J.M.); (G.D.P.); (B.T.); (Y.L.); (D.B.); (S.J.M.)
| | - Grant D. Phillips
- Division of Cellular & Systems Medicine, School of Medicine, Medical Sciences Institute, Dundee University, Dow Street, Dundee DD1 5HL, UK; (S.J.M.); (G.D.P.); (B.T.); (Y.L.); (D.B.); (S.J.M.)
| | - Becks Tench
- Division of Cellular & Systems Medicine, School of Medicine, Medical Sciences Institute, Dundee University, Dow Street, Dundee DD1 5HL, UK; (S.J.M.); (G.D.P.); (B.T.); (Y.L.); (D.B.); (S.J.M.)
| | - Yunkai Li
- Division of Cellular & Systems Medicine, School of Medicine, Medical Sciences Institute, Dundee University, Dow Street, Dundee DD1 5HL, UK; (S.J.M.); (G.D.P.); (B.T.); (Y.L.); (D.B.); (S.J.M.)
| | - Delia Belelli
- Division of Cellular & Systems Medicine, School of Medicine, Medical Sciences Institute, Dundee University, Dow Street, Dundee DD1 5HL, UK; (S.J.M.); (G.D.P.); (B.T.); (Y.L.); (D.B.); (S.J.M.)
| | - Stephen J. Martin
- Division of Cellular & Systems Medicine, School of Medicine, Medical Sciences Institute, Dundee University, Dow Street, Dundee DD1 5HL, UK; (S.J.M.); (G.D.P.); (B.T.); (Y.L.); (D.B.); (S.J.M.)
| | - Jerome D. Swinny
- School of Pharmacy & Biomedical Sciences, St. Michael’s Building, University of Portsmouth, White Swan Road, Portsmouth PO1 2DT, UK; (J.D.S.); (L.K.)
| | - Louise Kelly
- School of Pharmacy & Biomedical Sciences, St. Michael’s Building, University of Portsmouth, White Swan Road, Portsmouth PO1 2DT, UK; (J.D.S.); (L.K.)
| | - John R. Atack
- Main Building, Medicines Discovery Institute, Park Place, Cardiff University, Cardiff, CF10 3AT, UK; (J.R.A.); (M.P.)
| | - Michael Paradowski
- Main Building, Medicines Discovery Institute, Park Place, Cardiff University, Cardiff, CF10 3AT, UK; (J.R.A.); (M.P.)
| | - Jeremy J. Lambert
- Division of Cellular & Systems Medicine, School of Medicine, Medical Sciences Institute, Dundee University, Dow Street, Dundee DD1 5HL, UK; (S.J.M.); (G.D.P.); (B.T.); (Y.L.); (D.B.); (S.J.M.)
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4
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Macpherson T, Dixon CI, Robertson J, Sindarto MM, Janak PH, Belelli D, Lambert JJ, Stephens DN, King SL. α4-Containing GABA A Receptors on DRD2 Neurons of the Nucleus Accumbens Mediate Instrumental Responding for Conditioned Reinforcers and Its Potentiation by Cocaine. eNeuro 2023; 10:ENEURO.0236-23.2023. [PMID: 37553242 PMCID: PMC10470850 DOI: 10.1523/eneuro.0236-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 07/11/2023] [Indexed: 08/10/2023] Open
Abstract
Extrasynaptic GABAA receptors (GABAARs) composed of α4, β, and δ subunits mediate GABAergic tonic inhibition and are potential molecular targets in the modulation of behavioral responses to natural and drug rewards. These GABAARs are highly expressed within the nucleus accumbens (NAc), where they influence the excitability of the medium spiny neurons. Here, we explore their role in modulating behavioral responses to food-conditioned cues and the behavior-potentiating effects of cocaine. α4-Subunit constitutive knock-out mice (α4-/-) showed higher rates of instrumental responding for reward-paired stimuli in a test of conditioned reinforcement (CRf). A similar effect was seen following viral knockdown of GABAAR α4 subunits within the NAc. Local infusion of the α4βδ-GABAAR-preferring agonist THIP (4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol; Gaboxadol) into the NAc had no effect on responding when given alone but reduced cocaine potentiation of responding for conditioned reinforcers in wild-type, but not α4-/- mice. Finally, specific deletion of α4-subunits from dopamine D2, but not D1, receptor-expressing neurons (DRD2 and DRD1 neurons), mimicked the phenotype of the constitutive knockout, potentiating CRf responding, and blocking intra-accumbal THIP attenuation of cocaine-potentiated CRf responding. These data demonstrate that α4-GABAAR-mediated inhibition of DRD2 neurons reduces instrumental responding for a conditioned reinforcer and its potentiation by cocaine and emphasize the importance of GABAergic signaling within the NAc in mediating the effects of cocaine.
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Affiliation(s)
- Tom Macpherson
- Sussex Neuroscience, School of Psychology, University of Sussex, Brighton BN1 9QG, United Kingdom
- Laboratory for Advanced Brain Functions, Institute for Protein Research, Osaka University, Suita 565-0871, Japan
| | - Claire I. Dixon
- Sussex Neuroscience, School of Psychology, University of Sussex, Brighton BN1 9QG, United Kingdom
| | - Jonathan Robertson
- Sussex Neuroscience, School of Psychology, University of Sussex, Brighton BN1 9QG, United Kingdom
| | - Marsha M. Sindarto
- Sussex Neuroscience, School of Psychology, University of Sussex, Brighton BN1 9QG, United Kingdom
| | - Patricia H. Janak
- Department of Psychological and Brain Sciences, Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore, Maryland 21218
| | - Delia Belelli
- Division of Neuroscience, Medical Research Institute, Ninewells Hospital & Medical School, University of Dundee, Dundee DD1 9SY, United Kingdom
| | - Jeremy J. Lambert
- Division of Neuroscience, Medical Research Institute, Ninewells Hospital & Medical School, University of Dundee, Dundee DD1 9SY, United Kingdom
| | - David N. Stephens
- Sussex Neuroscience, School of Psychology, University of Sussex, Brighton BN1 9QG, United Kingdom
| | - Sarah L. King
- Sussex Neuroscience, School of Psychology, University of Sussex, Brighton BN1 9QG, United Kingdom
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5
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Konar-Nié M, Guzman-Castillo A, Armijo-Weingart L, Aguayo LG. Aging in nucleus accumbens and its impact on alcohol use disorders. Alcohol 2023; 107:73-90. [PMID: 36087859 DOI: 10.1016/j.alcohol.2022.08.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 08/01/2022] [Accepted: 08/04/2022] [Indexed: 02/06/2023]
Abstract
Ethanol is one of the most widely consumed drugs in the world and prolonged excessive ethanol intake might lead to alcohol use disorders (AUDs), which are characterized by neuroadaptations in different brain regions, such as in the reward circuitry. In addition, the global population is aging, and it appears that they are increasing their ethanol consumption. Although research involving the effects of alcohol in aging subjects is limited, differential effects have been described. For example, studies in human subjects show that older adults perform worse in tests assessing working memory, attention, and cognition as compared to younger adults. Interestingly, in the field of the neurobiological basis of ethanol actions, there is a significant dichotomy between what we know about the effects of ethanol on neurochemical targets in young animals and how it might affect them in the aging brain. To be able to understand the distinct effects of ethanol in the aging brain, the following questions need to be answered: (1) How does physiological aging impact the function of an ethanol-relevant region (e.g., the nucleus accumbens)? and (2) How does ethanol affect these neurobiological systems in the aged brain? This review discusses the available data to try to understand how aging affects the nucleus accumbens (nAc) and its neurochemical response to alcohol. The data show that there is little information on the effects of ethanol in aged mice and rats, and that many studies had considered 2-3-month-old mice as adults, which needs to be reconsidered since more recent literature defines 6 months as young adults and >18 months as an older mouse. Considering the actual relevance of an aged worldwide population and that this segment is drinking more frequently, it appears at least reasonable to explore how ethanol affects the brain in adult and aged models.
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Affiliation(s)
- Macarena Konar-Nié
- Laboratory of Neurophysiology, Department of Physiology, Universidad de Concepcion, Concepcion, Chile.
| | - Alejandra Guzman-Castillo
- Laboratory of Neurophysiology, Department of Physiology, Universidad de Concepcion, Concepcion, Chile; Programa en Neurociencia, Psiquiatría y Salud Mental, Universidad de Concepción, Concepcion, Chile.
| | - Lorena Armijo-Weingart
- Laboratory of Neurophysiology, Department of Physiology, Universidad de Concepcion, Concepcion, Chile; Programa en Neurociencia, Psiquiatría y Salud Mental, Universidad de Concepción, Concepcion, Chile.
| | - Luis Gerardo Aguayo
- Laboratory of Neurophysiology, Department of Physiology, Universidad de Concepcion, Concepcion, Chile; Programa en Neurociencia, Psiquiatría y Salud Mental, Universidad de Concepción, Concepcion, Chile.
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6
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Giacometti LL, Buck LA, Barker JM. Estrous cycle and hormone regulation of stress-induced reinstatement of reward seeking in female mice. ADDICTION NEUROSCIENCE 2022; 4:100035. [PMID: 36540408 PMCID: PMC9762733 DOI: 10.1016/j.addicn.2022.100035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Women are more vulnerable to stress-induced craving, which may be associated with increased vulnerability to relapse. Susceptibility to stress-induced craving also appears to be modulated by the menstrual cycle and is negatively correlated with circulating progesterone levels in women. However, the factors that contribute to relapse vulnerability are poorly characterized in female animals. In this study, we assessed whether chronic ethanol exposure, estrous cycle, or exogenous progesterone administration modulated vulnerability to stress-induced reinstatement. To model ethanol dependence, adult female C57Bl/6J mice underwent chronic intermittent ethanol (CIE) exposure via vapor inhalation. Seventy-two hours after the final ethanol exposure, food-restricted mice began training in a conditioned place preference paradigm (CPP) for a food reward, followed by extinction training. Mice were then subjected to forced swim stress and assessed for reinstatement of their preference for the reward-paired chamber. CIE did not affect stress-induced reinstatement. However, stress-induced reinstatement was attenuated during the diestrus phase, when endogenous levels of progesterone peak in female mice. Further, administration of exogenous progesterone mimicked the attenuated reinstatement observed in diestrus. These findings indicate that circulating hormone levels modulate susceptibility to relapse-like behaviors and implicate progesterone as a potential target for treating stress-induced relapse in women.
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7
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Floris G, Asuni GP, Talani G, Biggio F, Pisu MG, Zanda MT, Contu L, Maciocco E, Serra M, Follesa P. Increased Voluntary Alcohol Consumption in Mice Lacking GABA B(1) Is Associated With Functional Changes in Hippocampal GABA A Receptors. Front Behav Neurosci 2022; 16:893835. [PMID: 35755407 PMCID: PMC9218813 DOI: 10.3389/fnbeh.2022.893835] [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: 03/10/2022] [Accepted: 05/09/2022] [Indexed: 11/26/2022] Open
Abstract
Gamma-aminobutyric acid type B receptor (GABABR) has been extensively involved in alcohol use disorders; however, the mechanisms by which this receptor modulates alcohol drinking behavior remain murky. In this study, we investigate alcohol consumption and preference in mice lacking functional GABABR using the 2-bottle choice paradigm. We found that GABAB(1), knockout (KO), and heterozygous (HZ) mice drank higher amounts of an alcoholic solution, preferred alcohol to water, and reached higher blood alcohol concentrations (BACs) compared to wild-type (WT) littermates. The GABABR agonist GHB significantly reduced alcohol consumption in the GABAB(1) HZ and WT but not in the KO mice. Next, because of a functional crosstalk between GABABR and δ-containing GABAA receptor (δ-GABAAR), we profiled δ subunit mRNA expression levels in brain regions in which the crosstalk was characterized. We found a loss of the alcohol-sensitive GABAAR δ subunit in the hippocampus of the GABAB(1) KO alcohol-naïve mice that was associated with increased ɣ2 subunit abundance. Electrophysiological recordings revealed that these molecular changes were associated with increased phasic inhibition, suggesting a potential gain of synaptic GABAAR responsiveness to alcohol that has been previously described in an animal model of excessive alcohol drinking. Interestingly, voluntary alcohol consumption did not revert the dramatic loss of hippocampal δ-GABAAR occurring in the GABAB(1) KO mice but rather exacerbated this condition. Finally, we profiled hippocampal neuroactive steroids levels following acute alcohols administration in the GABAB(1) KO and WT mice because of previous involvement of GABABR in the regulation of cerebral levels of these compounds. We found that systemic administration of alcohol (1.5 g/kg) did not produce alcohol-induced neurosteroid response in the GABAB(1) KO mice but elicited an expected increase in the hippocampal level of progesterone and 3α,5α-THP in the WT controls. In conclusion, we show that genetic ablation of the GABAB(1) subunit results in increased alcohol consumption and preference that were associated with functional changes in hippocampal GABAAR, suggesting a potential mechanism by which preference for alcohol consumption is maintained in the GABAB(1) KO mice. In addition, we documented that GABAB(1) deficiency results in lack of alcohol-induced neurosteroids, and we discussed the potential implications of this finding in the context of alcohol drinking and dependence.
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Affiliation(s)
- Gabriele Floris
- Department of Life and Environment Sciences, Section of Neuroscience and Anthropology, University of Cagliari, Cagliari, Italy
| | - Gino Paolo Asuni
- Department of Life and Environment Sciences, Section of Neuroscience and Anthropology, University of Cagliari, Cagliari, Italy
| | - Giuseppe Talani
- Institute of Neuroscience-Cagliari, National Research Council, Cagliari, Italy
| | - Francesca Biggio
- Department of Life and Environment Sciences, Section of Neuroscience and Anthropology, University of Cagliari, Cagliari, Italy
| | | | - Mary Tresa Zanda
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Liliana Contu
- Department of Life and Environment Sciences, Section of Neuroscience and Anthropology, University of Cagliari, Cagliari, Italy
| | - Elisabetta Maciocco
- Institute of Neuroscience-Cagliari, National Research Council, Cagliari, Italy
| | - Mariangela Serra
- Department of Life and Environment Sciences, Section of Neuroscience and Anthropology, University of Cagliari, Cagliari, Italy
| | - Paolo Follesa
- Department of Life and Environment Sciences, Section of Neuroscience and Anthropology, University of Cagliari, Cagliari, Italy
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King CP, Meyer PJ. The incentive amplifying effects of nicotine: Roles in alcohol seeking and consumption. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2022; 93:171-218. [PMID: 35341566 DOI: 10.1016/bs.apha.2021.10.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Nicotine has a unique profile among drugs of abuse. To the noninitiated user, nicotine has powerful aversive effects and its relatively weak euphorigenic effects undergo rapid tolerance. Despite this, nicotine is commonly abused despite negative heath consequences, and nicotine users have enormous difficulty quitting. Further, nicotine is one of the most commonly co-abused substances, in that it is often taken in combination with other drugs. One explanation of this polydrug use is that nicotine has multiple appetitive and consummatory conditioning effects. For example, nicotine is a reinforcement enhancer in that it can potently increase the incentive value of other stimuli, including those surrounding drugs of abuse such as alcohol. In addition, nicotine also has a unique profile of neurobiological effects that alter regulation of alcohol intake and interoception. This review discusses the psychological and biological mechanisms surrounding nicotine's appetitive conditioning and consummatory effects, particularly its interactions with alcohol.
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Affiliation(s)
- Christopher P King
- Department of Psychology, State University of New York at Buffalo, Buffalo, NY, United States; Clinical and Research Institute on Addictions, State University of New York at Buffalo, Buffalo, NY, United States
| | - Paul J Meyer
- Department of Psychology, State University of New York at Buffalo, Buffalo, NY, United States.
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9
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Yorgason JT, Wadsworth HA, Anderson EJ, Williams BM, Brundage JN, Hedges DM, Stockard AL, Jones ST, Arthur SB, Hansen DM, Schilaty ND, Jang EY, Lee AM, Wallner M, Steffensen SC. Modulation of dopamine release by ethanol is mediated by atypical GABA A receptors on cholinergic interneurons in the nucleus accumbens. Addict Biol 2022; 27:e13108. [PMID: 34713509 DOI: 10.1111/adb.13108] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 08/31/2021] [Accepted: 09/24/2021] [Indexed: 12/18/2022]
Abstract
Previous studies indicate that moderate-to-high ethanol (EtOH) concentrations enhance dopamine (DA) neurotransmission in the mesolimbic DA system from the ventral tegmental area (VTA) and projecting to the nucleus accumbens core (NAc). However, voltammetry studies demonstrate that moderate-to-high EtOH concentrations decrease evoked DA release at NAc terminals. The involvement of γ-aminobutyric acid (GABA) receptors (GABAA Rs), glycine (GLY) receptors (GLYRs) and cholinergic interneurons (CINs) in mediating EtOH inhibition of evoked NAc DA release were examined. Fast scan cyclic voltammetry, electrophysiology, optogenetics and immunohistochemistry techniques were used to evaluate the effects of acute and chronic EtOH exposure on DA release and CIN activity in C57/BL6, CD-1, transgenic mice and δ-subunit knockout (KO) mice (δ-/-). Ethanol decreased DA release in mice with an IC50 of 80 mM ex vivo and 2.0 g/kg in vivo. GABA and GLY decreased evoked DA release at 1-10 mM. Typical GABAA R agonists inhibited DA release at high concentrations. Typical GABAA R antagonists had minimal effects on EtOH inhibition of evoked DA release. However, EtOH inhibition of DA release was blocked by the α4 β3 δ GABAA R antagonist Ro15-4513, the GLYR antagonist strychnine and by the GABA ρ1 (Rho-1) antagonist TPMPA (10 μM) and reduced significantly in GABAA R δ-/- mice. Rho-1 expression was observed in CINs. Ethanol inhibited GABAergic synaptic input to CINs from the VTA and enhanced firing rate, both of which were blocked by TPMPA. Results herein suggest that EtOH inhibition of DA release in the NAc is modulated by GLYRs and atypical GABAA Rs on CINs containing δ- and Rho-subunits.
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Affiliation(s)
- Jordan T Yorgason
- Department of Cellular Biology and Physiology, Brigham Young University, Provo, Utah, USA
| | - Hillary A Wadsworth
- Department of Psychology and Center for Neuroscience, Brigham Young University, Provo, Utah, USA
| | - Elizabeth J Anderson
- Department of Psychology and Center for Neuroscience, Brigham Young University, Provo, Utah, USA
| | - Benjamin M Williams
- Department of Psychology and Center for Neuroscience, Brigham Young University, Provo, Utah, USA
| | - James N Brundage
- Department of Psychology and Center for Neuroscience, Brigham Young University, Provo, Utah, USA
| | - David M Hedges
- Enterprise Information Management, Billings Clinic, Billings, Montana, USA
| | - Alyssa L Stockard
- Department of Psychology and Center for Neuroscience, Brigham Young University, Provo, Utah, USA
| | - Stephen T Jones
- Department of Psychology and Center for Neuroscience, Brigham Young University, Provo, Utah, USA
| | - Summer B Arthur
- Department of Psychology and Center for Neuroscience, Brigham Young University, Provo, Utah, USA
| | - David Micah Hansen
- Department of Psychology and Center for Neuroscience, Brigham Young University, Provo, Utah, USA
| | - Nathan D Schilaty
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States
| | - Eun Young Jang
- Research Center for Convergence Toxicology, Korea Institute of Toxicology, Daejeon, South Korea
| | - Anna M Lee
- Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Martin Wallner
- Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, California, USA
| | - Scott C Steffensen
- Department of Psychology and Center for Neuroscience, Brigham Young University, Provo, Utah, USA
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10
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Xie X, Gu J, Zhuang D, Chen X, Zhou Y, Shen W, Li L, Liu Y, Xu W, Hong Q, Chen W, Zhou W, Liu H. Association study of genetic polymorphisms in GABRD with treatment response and dose in methadone maintenance treatment. Per Med 2021; 18:423-430. [PMID: 34160285 DOI: 10.2217/pme-2021-0063] [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] [Indexed: 02/08/2023]
Abstract
Aim: This study determined if gene variants in the GABA receptor delta subunit (GABRD) are associated with treatment response and dose in methadone maintenance treatment (MMT) for heroin addiction. Materials & methods: A total of 286 MMT patients were recruited and divided into response and nonresponse groups based on retention time in therapy. A total of 177 responders were classified into low dose and high dose subgroups according to the stabilized methadone dose. Four (single nucleotide polymorphisms) SNPs (rs13303344, rs4481796, rs2376805 and rs2229110) in GABRD were genotyped using the TaqMan SNP assay. Logistic regression was used to assess the genetic effects of the SNPs in MMT. Results: No significant associations were observed between the SNPs and treatment response or dose, except the frequency of haplotype ACGC at the four SNPs significantly differed between responders and nonresponders. Conclusion: The results indicated that GABRD variants may play a small role in modulating methadone treatment response.
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Affiliation(s)
- Xiaohu Xie
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, Ningbo, Zhejiang, China
| | - Jun Gu
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, Ningbo, Zhejiang, China
| | - Dingding Zhuang
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, Ningbo, Zhejiang, China
| | - Xiaoyu Chen
- School of Medicine, Ningbo University, Ningbo, Zhejiang, China
| | - Yun Zhou
- School of Medicine, Ningbo University, Ningbo, Zhejiang, China
| | - Wenwen Shen
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, Ningbo, Zhejiang, China
| | - Longhui Li
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, Ningbo, Zhejiang, China
| | - Yue Liu
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, Ningbo, Zhejiang, China
| | - Wenjin Xu
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, Ningbo, Zhejiang, China
| | - Qingxiao Hong
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, Ningbo, Zhejiang, China
| | - Weisheng Chen
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, Ningbo, Zhejiang, China
| | - Wenhua Zhou
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, Ningbo, Zhejiang, China.,School of Medicine, Ningbo University, Ningbo, Zhejiang, China
| | - Huifen Liu
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, Ningbo, Zhejiang, China.,School of Medicine, Ningbo University, Ningbo, Zhejiang, China
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11
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Jovasevic V, Radulovic J. High ethanol preference and dissociated memory are co-occurring phenotypes associated with hippocampal GABA AR-δ receptor levels. Neurobiol Learn Mem 2021; 183:107459. [PMID: 34015441 DOI: 10.1016/j.nlm.2021.107459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 04/26/2021] [Accepted: 05/12/2021] [Indexed: 11/20/2022]
Abstract
Alcohol use disorder (AUD) frequently co-occurs with dissociative disorders and disorders with dissociative symptoms, suggesting a common neurobiological basis. It has been proposed that facilitated information processing under the influence of alcohol, resulting in the formation of dissociated memories, might be an important factor controlling alcohol use. Access to such memories is facilitated under the effect of alcohol, thus further reinforcing alcohol use. To interrogate possible mechanisms associated with these phenotypes, we used a mouse model of dissociative amnesia, combined with a high-alcohol preferring (HAP) model of AUD. Dissociated memory was induced by activation of hippocampal extrasynaptic GABA type A receptor delta subunits (GABAAR-δ), which control tonic inhibition and to which ethanol binds with high affinity. Increased ethanol preference was associated with increased propensity to form dissociated memories dependent on GABAAR-δ in the dorsal hippocampus (DH). Furthermore, the DH level of GABAAR-δ protein, but not mRNA, was increased in HAP mice, and was inversely correlated to the level of miR-365-3p, suggesting an miRNA-mediated post-transcriptional mechanism contributing to elevated GABAAR-δ. The observed changes of DH GABAAR-δ were associated with a severe reduction of excitatory projections stemming from GABAAR-δ-containing pyramidal neurons in the subiculum and terminating in the mammillary body. These results suggest that both molecular and circuit dysfunction involving hippocampal GABAAR-δ receptors might contribute to the co-occurrence of ethanol preference and dissociated information processing.
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Affiliation(s)
| | - Jelena Radulovic
- Department of Pharmacology, Northwestern University, Chicago, IL, USA; Department of Neuroscience and Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, Bronx, NY, USA.
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12
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Xie X, Gu J, Zhuang D, Shen W, Li L, Liu Y, Xu W, Hong Q, Chen W, Zhou W, Liu H. Association between GABA receptor delta subunit gene polymorphisms and heroin addiction. Neurosci Lett 2021; 755:135905. [PMID: 33887383 DOI: 10.1016/j.neulet.2021.135905] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 04/15/2021] [Accepted: 04/15/2021] [Indexed: 12/18/2022]
Abstract
Evidence suggests that γ-aminobutyric acid (GABA) receptors are involved in the development of drug dependence. Considering its exclusively extrasynaptic localization, GABA receptor delta subunit (GABRD) is likely involved in heroin addiction. The purpose of this study was to explore the association between the single nucleotide polymorphisms (SNPs) of GABRD and heroin addiction. Genotyping of five SNPs (rs13303344, rs4481796, rs2376805, rs2229110, and rs41307846) in GABRD gene was performed by using TaqMan SNP assay. The association between heroin addiction and these SNPs was assessed in 446 heroin dependent patients and 400 normal control subjects of male Han Chinese origin. Only the genotype and allele frequencies at rs13303344 differed significantly between the cases and controls (nominal P values were 0.028 and 0.019, respectively). The C allele of rs13303344 was associated with an increased risk of heroin addiction (OR = 1.281, 95 % CI: 1.042-1.575). After Bonferroni correction, the association lost significance. The frequencies of the haplotype C-C-A and A-C-A at GARBD (rs13303344-rs4481796- rs2376805) differed significantly between the cases and controls. The heroin craving score was significantly higher in patients with CC/AC genotypes at rs13303344 than in those with the AA genotype (nominal P = 0.017). The results suggest that GABRD rs13303344 may contribute to the susceptibility to heroin addiction and is associated with the drug cravings of heroin dependent patients.
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Affiliation(s)
- Xiaohu Xie
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, School of Medicine, Ningbo University, Ningbo, Zhejiang, China.
| | - Jun Gu
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, School of Medicine, Ningbo University, Ningbo, Zhejiang, China
| | - Dingding Zhuang
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, School of Medicine, Ningbo University, Ningbo, Zhejiang, China
| | - Wenwen Shen
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, School of Medicine, Ningbo University, Ningbo, Zhejiang, China
| | - Longhui Li
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, School of Medicine, Ningbo University, Ningbo, Zhejiang, China
| | - Yue Liu
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, School of Medicine, Ningbo University, Ningbo, Zhejiang, China
| | - Wenjin Xu
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, School of Medicine, Ningbo University, Ningbo, Zhejiang, China
| | - Qingxiao Hong
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, School of Medicine, Ningbo University, Ningbo, Zhejiang, China
| | - Weisheng Chen
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, School of Medicine, Ningbo University, Ningbo, Zhejiang, China
| | - Wenhua Zhou
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, School of Medicine, Ningbo University, Ningbo, Zhejiang, China.
| | - Huifen Liu
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, School of Medicine, Ningbo University, Ningbo, Zhejiang, China.
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13
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Radke AK, Sneddon EA, Frasier RM, Hopf FW. Recent Perspectives on Sex Differences in Compulsion-Like and Binge Alcohol Drinking. Int J Mol Sci 2021; 22:ijms22073788. [PMID: 33917517 PMCID: PMC8038761 DOI: 10.3390/ijms22073788] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/31/2021] [Accepted: 04/02/2021] [Indexed: 12/29/2022] Open
Abstract
Alcohol use disorder remains a substantial social, health, and economic problem and problem drinking levels in women have been increasing in recent years. Understanding whether and how the underlying mechanisms that drive drinking vary by sex is critical and could provide novel, more targeted therapeutic treatments. Here, we examine recent results from our laboratories and others which we believe provide useful insights into similarities and differences in alcohol drinking patterns across the sexes. Findings for binge intake and aversion-resistant, compulsion-like alcohol drinking are considered, since both are likely significant contributors to alcohol problems in humans. We also describe studies regarding mechanisms that may underlie sex differences in maladaptive alcohol drinking, with some focus on the importance of nucleus accumbens (NAcb) core and shell regions, several receptor types (dopamine, orexin, AMPA-type glutamate), and possible contributions of sex hormones. Finally, we discuss how stressors such as early life stress and anxiety-like states may interact with sex differences to contribute to alcohol drinking. Together, these findings underscore the importance and critical relevance of studying female and male mechanisms for alcohol and co-morbid conditions to gain a true and clinically useful understanding of addiction and neuropsychiatric mechanisms and treatment.
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Affiliation(s)
- Anna K. Radke
- Department of Psychology and Center for Neuroscience and Behavior, Miami University, Oxford, OH 45040, USA;
- Correspondence:
| | - Elizabeth A. Sneddon
- Department of Psychology and Center for Neuroscience and Behavior, Miami University, Oxford, OH 45040, USA;
| | - Raizel M. Frasier
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (R.M.F.); (F.W.H.)
| | - Frederic W. Hopf
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (R.M.F.); (F.W.H.)
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14
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Hong Q, Xu W, Lin Z, Liu J, Chen W, Zhu H, Lai M, Zhuang D, Xu Z, Fu D, Zhou W, Liu H. Role of GABRD Gene Methylation in the Nucleus Accumbens in Heroin-Seeking Behavior in Rats. Front Pharmacol 2021; 11:612200. [PMID: 33551813 PMCID: PMC7859445 DOI: 10.3389/fphar.2020.612200] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 11/27/2020] [Indexed: 11/13/2022] Open
Abstract
Epigenetic modifications such as DNA methylation play important roles in regulating gene expression and may mediate neuroplasticity and lead to drug-induced aberrant behaviors. Although several brain regions and neurobiological mechanisms have been suggested to be involved in these processes, there is remarkably little known about the effects of DNA methylation on heroin-seeking behavior. Using a Sprague-Dawley rat model, we show that heroin self-administration resulted in gamma-aminobutyric acid type A receptor subunit delta (GABRD) gene hypomethylation, which was associated with transcriptional upregulation of GABRD in the nucleus accumbens (NAc). Systemic l-methionine (MET) administration significantly strengthened the reinstatement of heroin-seeking behavior induced by heroin priming, whereas intra-NAc injections of the DNA methyltransferase (DNMT) inhibitor 5-aza-2'-deoxycytidine (5-Aza-dC) had the opposite effect on heroin-seeking. Meanwhile, 5-Aza-dC treatment decreased DNA methylation and upregulated the expression of GABRD in the NAc, whereas MET had the opposite effect. Our results also reveal that 5-Aza-dC might alter the methylation landscape of the GABRD gene by directly repressing DNMT1 and DNMT3A expression. Furthermore, reinstatement of heroin-seeking behavior was significantly inhibited by directly overexpressing GABRD and remarkably reinforced by GABRD gene silencing in the NAc. Collectively, these results suggest that targeting the GABRD gene and its methylation might represent a novel pharmacological strategy for treating heroin addiction and relapse.
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Affiliation(s)
- Qingxiao Hong
- Laboratory of Behavioral Neuroscience, Ningbo Kangning Hospital, Ningbo Institute of Microcirculation and Henbane, School of Medicine, Ningbo University, Ningbo, China
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo, China
| | - Wenjin Xu
- Laboratory of Behavioral Neuroscience, Ningbo Kangning Hospital, Ningbo Institute of Microcirculation and Henbane, School of Medicine, Ningbo University, Ningbo, China
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo, China
| | - Zi Lin
- Laboratory of Behavioral Neuroscience, Ningbo Kangning Hospital, Ningbo Institute of Microcirculation and Henbane, School of Medicine, Ningbo University, Ningbo, China
| | - Jing Liu
- Laboratory of Behavioral Neuroscience, Ningbo Kangning Hospital, Ningbo Institute of Microcirculation and Henbane, School of Medicine, Ningbo University, Ningbo, China
| | - Weisheng Chen
- Laboratory of Behavioral Neuroscience, Ningbo Kangning Hospital, Ningbo Institute of Microcirculation and Henbane, School of Medicine, Ningbo University, Ningbo, China
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo, China
| | - Huaqiang Zhu
- Laboratory of Behavioral Neuroscience, Ningbo Kangning Hospital, Ningbo Institute of Microcirculation and Henbane, School of Medicine, Ningbo University, Ningbo, China
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo, China
| | - Miaojun Lai
- Laboratory of Behavioral Neuroscience, Ningbo Kangning Hospital, Ningbo Institute of Microcirculation and Henbane, School of Medicine, Ningbo University, Ningbo, China
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo, China
| | - Dingding Zhuang
- Laboratory of Behavioral Neuroscience, Ningbo Kangning Hospital, Ningbo Institute of Microcirculation and Henbane, School of Medicine, Ningbo University, Ningbo, China
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo, China
| | - Zemin Xu
- Laboratory of Behavioral Neuroscience, Ningbo Kangning Hospital, Ningbo Institute of Microcirculation and Henbane, School of Medicine, Ningbo University, Ningbo, China
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo, China
| | - Dan Fu
- Laboratory of Behavioral Neuroscience, Ningbo Kangning Hospital, Ningbo Institute of Microcirculation and Henbane, School of Medicine, Ningbo University, Ningbo, China
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo, China
| | - Wenhua Zhou
- Laboratory of Behavioral Neuroscience, Ningbo Kangning Hospital, Ningbo Institute of Microcirculation and Henbane, School of Medicine, Ningbo University, Ningbo, China
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo, China
| | - Huifen Liu
- Laboratory of Behavioral Neuroscience, Ningbo Kangning Hospital, Ningbo Institute of Microcirculation and Henbane, School of Medicine, Ningbo University, Ningbo, China
- Key Laboratory of Addiction Research of Zhejiang Province, Ningbo, China
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15
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Vallöf D, Kalafateli AL, Jerlhag E. Brain region-specific neuromedin U signalling regulates alcohol-related behaviours and food intake in rodents. Addict Biol 2020; 25:e12764. [PMID: 31069918 PMCID: PMC7187236 DOI: 10.1111/adb.12764] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 03/26/2019] [Accepted: 03/27/2019] [Indexed: 12/21/2022]
Abstract
Albeit neuromedin U (NMU) attenuates alcohol‐mediated behaviours, its mechanisms of action are poorly defined. Providing that the behavioural effects of alcohol are processed within the nucleus accumbens (NAc) shell, anterior ventral tegmental area (aVTA), and laterodorsal tegmental area (LDTg), we assessed the involvement of NMU signalling in the aforementioned areas on alcohol‐mediated behaviours in rodents. We further examined the expression of NMU and NMU receptor 2 (NMUR2) in NAc and the dorsal striatum of high compared with low alcohol‐consuming rats, as this area is of importance in the maintenance of alcohol use disorder (AUD). Finally, we investigated the involvement of NAc shell, aVTA and LDTg in the consumption of chow and palatable peanut butter, to expand the link between NMU and reward‐related behaviours. We demonstrated here, that NMU into the NAc shell, but not aVTA or LDTg, blocked the ability of acute alcohol to cause locomotor stimulation and to induce memory retrieval of alcohol reward, as well as reduced peanut butter in mice. In addition, NMU into NAc shell decreased alcohol intake in rats. On a molecular level, we found increased NMU and decreased NMUR2 expression in the dorsal striatum in high compared with low alcohol‐consuming rats. Both aVTA and LDTg, rather than NAc shell, were identified as novel sites of action for NMU's anorexigenic properties in mice based on NMU's ability to selectively reduce chow intake when injected to these areas. Collectively, these data indicate that NMU signalling in different brain areas selectively modulates different behaviours.
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Affiliation(s)
- Daniel Vallöf
- Institute of Neuroscience and Physiology, Department of PharmacologyThe Sahlgrenska Academy at the University of Gothenburg Gothenburg Sweden
| | - Aimilia Lydia Kalafateli
- Institute of Neuroscience and Physiology, Department of PharmacologyThe Sahlgrenska Academy at the University of Gothenburg Gothenburg Sweden
| | - Elisabet Jerlhag
- Institute of Neuroscience and Physiology, Department of PharmacologyThe Sahlgrenska Academy at the University of Gothenburg Gothenburg Sweden
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16
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Landin JD, Gore-Langton JK, Varlinskaya EI, Spear LP, Werner DF. General Anesthetic Exposure During Early Adolescence Persistently Alters Ethanol Responses. Alcohol Clin Exp Res 2020; 44:611-619. [PMID: 32068904 PMCID: PMC7069780 DOI: 10.1111/acer.14291] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 01/15/2020] [Indexed: 11/26/2022]
Abstract
BACKGROUND Adolescent alcohol abuse can lead to behavioral dysfunction and chronic, relapsing alcohol use disorder (AUD) in adulthood. However, not all adolescents that consume alcohol will develop an AUD; therefore, it is critical to identify neural and environmental risk factors that contribute to increases in susceptibility to AUDs following adolescent alcohol (ethanol [EtOH]) exposure. We previously found that adolescent anesthetic exposure led to strikingly similar behavioral and neural effects as adolescent alcohol exposure. Therefore, we tested the hypothesis that general anesthetic exposure during early adolescence would alter EtOH responses consistent with an exacerbation of the adolescent alcohol phenotype. METHODS To test this hypothesis, early-adolescent male Sprague-Dawley rats were exposed for a short duration to the general anesthetic isoflurane and tested on multiple EtOH-induced behaviors in mid-late adolescence or adulthood. RESULTS Adolescent rats exposed to isoflurane exhibited decreases in sensitivity to negative properties of EtOH such as its aversive, hypnotic, and socially suppressive effects, as well as increases in voluntary EtOH intake and cognitive impairment. Select behaviors were noted to persist into adulthood following adolescent isoflurane exposure. Similar exposure in adults had no effects on EtOH sensitivity. CONCLUSIONS This study demonstrates for the first time that early-adolescent isoflurane exposure alters EtOH sensitivity in a manner consistent with an exacerbation of adolescent-typical alcohol responding. These findings suggest that general anesthetic exposure during adolescence may be an environmental risk factor contributing to an enhanced susceptibility to developing AUDs in an already vulnerable population.
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Affiliation(s)
- Justine D. Landin
- Department of Psychology and Center for Development and Behavioral Neuroscience, Binghamton University – State University of New York, Binghamton, NY, 13902 USA
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, 29425 USA
| | - Jonathan K. Gore-Langton
- Department of Psychology and Center for Development and Behavioral Neuroscience, Binghamton University – State University of New York, Binghamton, NY, 13902 USA
| | - Elena I. Varlinskaya
- Department of Psychology and Center for Development and Behavioral Neuroscience, Binghamton University – State University of New York, Binghamton, NY, 13902 USA
| | - Linda P. Spear
- Department of Psychology and Center for Development and Behavioral Neuroscience, Binghamton University – State University of New York, Binghamton, NY, 13902 USA
| | - David F. Werner
- Department of Psychology and Center for Development and Behavioral Neuroscience, Binghamton University – State University of New York, Binghamton, NY, 13902 USA
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17
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Bartolomé I, Llidó A, Darbra S, Pallarès M. Early postnatal allopregnanolone levels alteration and adult behavioral disruption in rats: Implication for drug abuse. Neurobiol Stress 2019; 12:100208. [PMID: 32435661 PMCID: PMC7231993 DOI: 10.1016/j.ynstr.2019.100208] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 11/14/2019] [Accepted: 12/23/2019] [Indexed: 02/01/2023] Open
Abstract
Several studies have highlighted the role that early postnatal levels of allopregnanolone play in the development of the CNS and adult behavior. Changes in allopregnanolone levels related to stress have been observed during early postnatal periods, and perinatal stress has been linked to neuropsychiatric disorders. The alteration of early postnatal allopregnanolone levels in the first weeks of life has been proven to affect adult behaviors, such as anxiety-related behaviors and the processing of sensory inputs. This review focuses on the first studies about the possible relationship between the early postnatal allopregnanolone levels and the vulnerability to abuse of drugs such as alcohol in adulthood, given that (1) changes in neonatal allopregnanolone levels affect novelty exploration and novelty seeking has been linked to vulnerability to drug abuse; (2) early postnatal administration of progesterone, the main allopregnanolone precursor, affects the maturation of dopaminergic meso-striatal systems, which have been related to novelty seeking and drug abuse; and (3) alcohol consumption increases plasma and brain allopregnanolone levels in animals and humans. Manipulating neonatal allopregnanolone by administering finasteride, an inhibitor of the 5α-reductase enzyme that participates in allopregnanolone synthesis, increases alcohol consumption and decreases the locomotor stimulant effects of low alcohol doses. At a molecular level, finasteride decreases dopamine and serotonin in ventral striatum and dopamine release in nucleus accumbens. Preliminary results suggest that serotonin 5HT3 receptors could also be affected. Although an in-depth study is necessary, evidence suggests that there is a relation between early postnatal allopregnanolone and vulnerability to drug use/abuse. Early postnatal AlloP levels alteration affects brain maturation and adult behavior. Early stress interacts to AlloP influencing neuropsychiatric disorders vulnerability. Fluctuations in neonatal AlloP levels play a role in alcohol abuse vulnerability. Neonatal finasteride induces novelty-seeking profile and increases ethanol intake.
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Affiliation(s)
- Iris Bartolomé
- Institut de Neurociències, Departament de Psicobiologia I Metodologia en Ciències de La Salut, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain
| | - Anna Llidó
- Institut de Neurociències, Departament de Psicobiologia I Metodologia en Ciències de La Salut, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain
| | - Sònia Darbra
- Institut de Neurociències, Departament de Psicobiologia I Metodologia en Ciències de La Salut, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain
| | - Marc Pallarès
- Institut de Neurociències, Departament de Psicobiologia I Metodologia en Ciències de La Salut, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain
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18
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Kardos J, Dobolyi Á, Szabó Z, Simon Á, Lourmet G, Palkovits M, Héja L. Molecular Plasticity of the Nucleus Accumbens Revisited-Astrocytic Waves Shall Rise. Mol Neurobiol 2019; 56:7950-7965. [PMID: 31134458 PMCID: PMC6834761 DOI: 10.1007/s12035-019-1641-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 05/06/2019] [Indexed: 12/11/2022]
Abstract
Part of the ventral striatal division, the nucleus accumbens (NAc) drives the circuit activity of an entire macrosystem about reward like a "flagship," signaling and leading diverse conducts. Accordingly, NAc neurons feature complex inhibitory phenotypes that assemble to process circuit inputs and generate outputs by exploiting specific arrays of opposite and/or parallel neurotransmitters, neuromodulatory peptides. The resulting complex combinations enable versatile yet specific forms of accumbal circuit plasticity, including maladaptive behaviors. Although reward signaling and behavior are elaborately linked to neuronal circuit activities, it is plausible to propose whether these neuronal ensembles and synaptic islands can be directly controlled by astrocytes, a powerful modulator of neuronal activity. Pioneering studies showed that astrocytes in the NAc sense citrate cycle metabolites and/or ATP and may induce recurrent activation. We argue that the astrocytic calcium, GABA, and Glu signaling and altered sodium and chloride dynamics fundamentally shape metaplasticity by providing active regulatory roles in the synapse- and network-level flexibility of the NAc.
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Affiliation(s)
- Julianna Kardos
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, Budapest, 1117, Hungary.
| | - Árpád Dobolyi
- Laboratory of Neuromorphology, Department of Anatomy, Histology and Embryology, Semmelweis University, Üllői út 26, Budapest, 1086, Hungary
- MTA-ELTE Laboratory of Molecular and Systems Neurobiology, Department of Physiology and Neurobiology, Eötvös Loránd University and the Hungarian Academy of Sciences, Pázmány Péter sétány 1C, Budapest, 1117, Hungary
| | - Zsolt Szabó
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, Budapest, 1117, Hungary
| | - Ágnes Simon
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, Budapest, 1117, Hungary
| | - Guillaume Lourmet
- Laboratory of Neuromorphology, Department of Anatomy, Histology and Embryology, Semmelweis University, Üllői út 26, Budapest, 1086, Hungary
| | - Miklós Palkovits
- Human Brain Tissue Bank, Semmelweis University, Tűzoltó utca 58, Budapest, H-1094, Hungary
| | - László Héja
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, Budapest, 1117, Hungary
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19
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Abstract
The term neurosteroid refers to rapid membrane actions of steroid hormones and their derivatives that can modulate physiological functions and behavior via their interactions with ligand-gated ion channels. This chapter will highlight recent advances pertaining to the modulatory effects of a select group of neurosteroids that are primarily potent positive allosteric modulators of γ-aminobutyric acidA receptors (GABAARs). Nanomolar concentrations of neurosteroids, which occur in vivo, potentiate phasic and tonic forms of GABAAR-mediated inhibition, indicating that both synaptic and extrasynaptic GABAARs possess sensitivity to neurosteroids and contribute to the overall ability of neurosteroids to modulate central nervous system excitability. Common effects of alcohol and neurosteroids at GABAARs have stimulated research on the ability of neurosteroids to modulate alcohol's acute and chronic effects. Background on neurosteroid pharmacology and biosynthetic enzymes will be provided as it relates to experimental findings. Data will be summarized on alcohol and neurosteroid interactions across neuroanatomical regions and models of intoxication, consumption, dependence, and withdrawal. Evidence supports independent regulation of neurosteroid synthesis between periphery and brain as well as across brain regions following acute alcohol administration and during withdrawal. Local mechanisms for fine-tuning neuronal excitability via manipulation of neurosteroid synthesis exert predicted behavioral and electrophysiological responses on GABAAR-mediated inhibition. Collectively, targeting neurosteroidogenesis may be a beneficial treatment strategy for alcohol use disorders.
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Darnieder LM, Melón LC, Do T, Walton NL, Miczek KA, Maguire JL. Female-specific decreases in alcohol binge-like drinking resulting from GABA A receptor delta-subunit knockdown in the VTA. Sci Rep 2019; 9:8102. [PMID: 31147611 PMCID: PMC6542821 DOI: 10.1038/s41598-019-44286-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 05/08/2019] [Indexed: 02/07/2023] Open
Abstract
Binge drinking is short-term drinking that achieves blood alcohol levels of 0.08 g/dl or above. It exhibits well-established sex differences in GABAergic inhibitory neurotransmission, including extrasynaptic δ subunit-containing GABAA receptors (δ-GABAARs) that mediate tonic inhibition, or synaptic γ2-containing GABAARs which underlie fast, synaptic, phasic inhibition have been implicated in sex differences in binge drinking. Ovarian hormones regulate δ-GABAARs, further implicating these receptors in potential sex differences. Here, we explored the contribution of extrasynaptic δ-GABAARs to male and female binge-like drinking in a critical area of mesolimbic circuitry-the ventral tegmental area (VTA). Quantitative PCR revealed higher Gabrd transcript levels and larger tonic currents in the VTA of females compared to males. In contrast, male and female Gabrg2 transcript levels and measures of phasic inhibition were equivalent. Intra-VTA infusion of AAV-Cre-GFP in floxed Gabrd mice downregulated δ-GABAARs and decreased binge-like drinking in females. There was no significant difference in either male or female mice after GABAAR γ2 subunit reduction in the VTA following AAV-Cre-GFP infusion in floxed Gabrg2 mice. Collectively, these findings suggest sex differences and GABAAR subunit specificity in alcohol intake.
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Affiliation(s)
- L M Darnieder
- Graduate Program in Neuroscience, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, MA, 02111, USA
| | - L C Melón
- Tufts University School of Medicine, Department of Neuroscience, Boston, MA, 02111, USA
| | - T Do
- Northeastern University, Bouvé College of Health Sciences, Boston, MA, 02115, USA
| | - N L Walton
- University of Massachusetts Boston, Honors College of Nursing and Health Sciences, Boston, MA, 02125, USA
| | - K A Miczek
- Tufts University School of Medicine, Department of Neuroscience, Boston, MA, 02111, USA
- Tufts University, Psychology Department, Medford, MA, 02155, USA
| | - J L Maguire
- Tufts University School of Medicine, Department of Neuroscience, Boston, MA, 02111, USA.
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General anesthetic exposure in adolescent rats causes persistent maladaptations in cognitive and affective behaviors and neuroplasticity. Neuropharmacology 2019; 150:153-163. [PMID: 30926450 DOI: 10.1016/j.neuropharm.2019.03.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 03/15/2019] [Accepted: 03/15/2019] [Indexed: 01/25/2023]
Abstract
Accumulating evidence indicates that exposure to general anesthetics during infancy and childhood can cause persistent cognitive impairment, alterations in synaptic plasticity, and, to a lesser extent, increased incidence of behavioral disorders. Unfortunately, the developmental parameters of susceptibility to general anesthetics are not well understood. Adolescence is a critical developmental period wherein multiple late developing brain regions may also be vulnerable to enduring general anesthetic effects. Given the breadth of the adolescent age span, this group potentially represents millions more individuals than those exposed during early childhood. In this study, isoflurane exposure within a well-characterized adolescent period in Sprague-Dawley rats elicited immediate and persistent anxiety- and impulsive-like responding, as well as delayed cognitive impairment into adulthood. These behavioral abnormalities were paralleled by atypical dendritic spine morphology in the prefrontal cortex (PFC) and hippocampus (HPC), suggesting delayed anatomical maturation, and shifts in inhibitory function that suggest hypermaturation of extrasynaptic GABAA receptor inhibition. Preventing this hypermaturation of extrasynaptic GABAA receptor-mediated function in the PFC selectively reversed enhanced impulsivity resulting from adolescent isoflurane exposure. Taken together, these data demonstrate that the developmental window for susceptibility to enduring untoward effects of general anesthetics may be much longer than previously appreciated, and those effects may include affective behaviors in addition to cognition.
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22
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Logrip ML. Molecular tools to elucidate factors regulating alcohol use. Alcohol 2019; 74:3-9. [PMID: 30033149 DOI: 10.1016/j.alcohol.2018.03.006] [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] [Received: 02/28/2018] [Revised: 03/15/2018] [Accepted: 03/15/2018] [Indexed: 12/20/2022]
Abstract
Alcohol use disorder (AUD) is a pervasive societal problem, marked by high levels of alcohol intake and recidivism. Despite these common disease traits, individuals diagnosed with AUD display a range of disordered drinking and alcohol-related behaviors. The diversity in disease presentation, as well as the established polygenic nature of the disorder and complex neurocircuitry, speaks to the variety of neurochemical changes resulting from alcohol intake that may differentially regulate alcohol-related behaviors. Investigations into the molecular adaptations responsible for maladaptive alcohol-related behavioral outcomes require an ever-evolving set of molecular tools to elucidate with increasing precision how alcohol alters behavior through neurochemical changes. This review highlights recent advances in molecular methodology, addressing how incorporation of these cutting-edge techniques not only may enhance current knowledge of the molecular bases of AUD, but also may facilitate identification of improved treatment targets that may be therapeutic in specific subpopulations of AUD individuals.
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Leggio GM, Di Marco R, Gulisano W, D'Ascenzo M, Torrisi SA, Geraci F, Lavanco G, Dahl K, Giurdanella G, Castorina A, Aitta-Aho T, Aceto G, Bucolo C, Puzzo D, Grassi C, Korpi ER, Drago F, Salomone S. Dopaminergic-GABAergic interplay and alcohol binge drinking. Pharmacol Res 2019; 141:384-391. [PMID: 30648615 DOI: 10.1016/j.phrs.2019.01.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 01/10/2019] [Accepted: 01/11/2019] [Indexed: 12/23/2022]
Abstract
The dopamine D3 receptor (D3R), in the nucleus accumbens (NAc), plays an important role in alcohol reward mechanisms. The major neuronal type within the NAc is the GABAergic medium spiny neuron (MSN), whose activity is regulated by dopaminergic inputs. We previously reported that genetic deletion or pharmacological blockade of D3R increases GABAA α6 subunit in the ventral striatum. Here we tested the hypothesis that D3R-dependent changes in GABAA α6 subunit in the NAc affect voluntary alcohol intake, by influencing the inhibitory transmission of MSNs. We performed in vivo and ex vivo experiments in D3R knockout (D3R -/-) mice and wild type littermates (D3R +/+). Ro 15-4513, a high affinity α6-GABAA ligand was used to study α6 activity. At baseline, NAc α6 expression was negligible in D3R+/+, whereas it was robust in D3R-/-; other relevant GABAA subunits were not changed. In situ hybridization and qPCR confirmed α6 subunit mRNA expression especially in the NAc. In the drinking-in-the-dark paradigm, systemic administration of Ro 15-4513 inhibited alcohol intake in D3R+/+, but increased it in D3R-/-; this was confirmed by intra-NAc administration of Ro 15-4513 and furosemide, a selective α6-GABAA antagonist. Whole-cell patch-clamp showed peak amplitudes of miniature inhibitory postsynaptic currents in NAc medium spiny neurons higher in D3R-/- compared to D3R+/+; Ro 15-4513 reduced the peak amplitude in the NAc of D3R-/-, but not in D3R+/+. We conclude that D3R-dependent enhanced expression of α6 GABAA subunit inhibits voluntary alcohol intake by increasing GABA inhibition in the NAc.
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Affiliation(s)
- Gian Marco Leggio
- Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, Catania, Italy
| | - Roberta Di Marco
- Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, Catania, Italy
| | - Walter Gulisano
- Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, Catania, Italy
| | - Marcello D'Ascenzo
- Institute of Human Physiology, Medical School, Università Cattolica, Rome, Italy; Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italia
| | - Sebastiano Alfio Torrisi
- Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, Catania, Italy
| | - Federica Geraci
- Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, Catania, Italy
| | - Gianluca Lavanco
- Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, Catania, Italy
| | - Kristiina Dahl
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Giovanni Giurdanella
- Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, Catania, Italy
| | - Alessandro Castorina
- Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, Catania, Italy
| | - Teemu Aitta-Aho
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Giuseppe Aceto
- Institute of Human Physiology, Medical School, Università Cattolica, Rome, Italy
| | - Claudio Bucolo
- Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, Catania, Italy
| | - Daniela Puzzo
- Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, Catania, Italy
| | - Claudio Grassi
- Institute of Human Physiology, Medical School, Università Cattolica, Rome, Italy; Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italia
| | - Esa R Korpi
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Filippo Drago
- Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, Catania, Italy
| | - Salvatore Salomone
- Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, Catania, Italy.
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Melón LC, Nasman JT, John AS, Mbonu K, Maguire JL. Interneuronal δ-GABA A receptors regulate binge drinking and are necessary for the behavioral effects of early withdrawal. Neuropsychopharmacology 2019; 44:425-434. [PMID: 30089884 PMCID: PMC6300562 DOI: 10.1038/s41386-018-0164-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 07/16/2018] [Accepted: 07/20/2018] [Indexed: 12/12/2022]
Abstract
Extensive evidence points to a role for GABAergic signaling in the amygdala in mediating the effects of alcohol, including presynaptic changes in GABA release, suggesting effects on GABAergic neurons. However, the majority of studies focus solely on the effects of alcohol on principal neurons. Here we demonstrate that δ-GABAARs, which have been suggested to confer ethanol sensitivity, are expressed at a high density on parvalbumin (PV) interneurons in the basolateral amygdala (BLA). Thus, we hypothesized that δ-GABAARs on PV interneurons may represent both an initial pharmacological target for alcohol and a site for plasticity associated with the expression of various behavioral maladaptations during withdrawal from binge drinking. To investigate this, we used a mouse model of voluntary alcohol intake (Drinking-in-the-Dark-Multiple Scheduled Access) to induce escalating heavy binge drinking and anxiety-like behavior in mice. This pattern of intake was associated with increased δ protein expression on parvalbumin positive interneurons in both the BLA and hippocampus. Loss of δ-GABAARs specifically in PV interneurons (PV:δ-/-) increased binge drinking behavior, reduced sensitivity to alcohol-induced motor incoordination, enhanced sensitivity to alcohol-induced hyperlocomotion and blocked the expression of withdrawal from binge drinking. This study is the first to demonstrate a role for δGABAARs specifically in PV-expressing interneurons in modulating binge alcohol intake and withdrawal-induced anxiety.
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Affiliation(s)
- Laverne C. Melón
- 0000 0000 8934 4045grid.67033.31Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111 USA
| | - James T. Nasman
- 0000 0000 8934 4045grid.67033.31Building Diversity in Biomedical Sciences, Tufts University School of Medicine, Boston, MA 02111 USA
| | - Ashley St. John
- 0000 0000 8934 4045grid.67033.31Building Diversity in Biomedical Sciences, Tufts University School of Medicine, Boston, MA 02111 USA
| | - Kenechukwu Mbonu
- 0000 0000 8934 4045grid.67033.31Building Diversity in Biomedical Sciences, Tufts University School of Medicine, Boston, MA 02111 USA
| | - Jamie L. Maguire
- 0000 0000 8934 4045grid.67033.31Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111 USA
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Ho AL, Salib AMN, Pendharkar AV, Sussman ES, Giardino WJ, Halpern CH. The nucleus accumbens and alcoholism: a target for deep brain stimulation. Neurosurg Focus 2018; 45:E12. [DOI: 10.3171/2018.5.focus18157] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Alcohol use disorder (AUD) is a difficult to treat condition with a significant global public health and cost burden. The nucleus accumbens (NAc) has been implicated in AUD and identified as an ideal target for deep brain stimulation (DBS). There are promising preclinical animal studies of DBS for alcohol consumption as well as some initial human clinical studies that have shown some promise at reducing alcohol-related cravings and, in some instances, achieving long-term abstinence. In this review, the authors discuss the evidence and concepts supporting the role of the NAc in AUD, summarize the findings from published NAc DBS studies in animal models and humans, and consider the challenges and propose future directions for neuromodulation of the NAc for the treatment of AUD.
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Affiliation(s)
| | - Anne-Mary N. Salib
- Departments of 1Neurosurgery and
- 2Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, California
| | | | | | - William J. Giardino
- 2Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, California
| | - Casey H. Halpern
- Departments of 1Neurosurgery and
- 2Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, California
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26
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The Cerebellar GABA AR System as a Potential Target for Treating Alcohol Use Disorder. Handb Exp Pharmacol 2018; 248:113-156. [PMID: 29736774 DOI: 10.1007/164_2018_109] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In the brain, fast inhibitory neurotransmission is mediated primarily by the ionotropic subtype of the gamma-aminobutyric acid (GABA) receptor subtype A (GABAAR). It is well established that the brain's GABAAR system mediates many aspects of neurobehavioral responses to alcohol (ethanol; EtOH). Accordingly, in both preclinical studies and some clinical scenarios, pharmacologically targeting the GABAAR system can alter neurobehavioral responses to acute and chronic EtOH consumption. However, many of the well-established interactions of EtOH and the GABAAR system have been identified at concentrations of EtOH ([EtOH]) that would only occur during abusive consumption of EtOH (≥40 mM), and there are still inadequate treatment options for prevention of or recovery from alcohol use disorder (AUD, including abuse and dependence). Accordingly, there is a general acknowledgement that more research is needed to identify and characterize: (1) neurobehavioral targets of lower [EtOH] and (2) associated brain structures that would involve such targets in a manner that may influence the development and maintenance of AUDs.Nearly 15 years ago it was discovered that the GABAAR system of the cerebellum is highly sensitive to EtOH, responding to concentrations as low as 10 mM (as would occur in the blood of a typical adult human after consuming 1-2 standard units of EtOH). This high sensitivity to EtOH, which likely mediates the well-known motor impairing effects of EtOH, combined with recent advances in our understanding of the role of the cerebellum in non-motor, cognitive/emotive/reward processes has renewed interest in this system in the specific context of AUD. In this chapter we will describe recent advances in our understanding of cerebellar processing, actions of EtOH on the cerebellar GABAAR system, and the potential relationship of such actions to the development of AUD. We will finish with speculation about how cerebellar specific GABAAR ligands might be effective pharmacological agents for treating aspects of AUD.
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Chandler CM, Overton JS, Rüedi-Bettschen D, Platt DM. GABA A Receptor Subtype Mechanisms and the Abuse-Related Effects of Ethanol: Genetic and Pharmacological Evidence. Handb Exp Pharmacol 2018; 248:3-27. [PMID: 29204713 DOI: 10.1007/164_2017_80] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Ethanol's reinforcing and subjective effects, as well as its ability to induce relapse, are powerful factors contributing to its widespread use and abuse. A significant mediator of these behavioral effects is the GABAA receptor system. GABAA receptors are the target for γ-aminobutyric acid (GABA), the major inhibitory neurotransmitter in the CNS. Structurally, they are pentameric, transmembrane chloride ion channels comprised of subunits from at least eight different families of distinct proteins. The contribution of different GABAA subunits to ethanol's diverse abuse-related effects is not clear and remains an area of research focus. This chapter details the clinical and preclinical findings supporting roles for different α, β, γ, and δ subunit-containing GABAA receptors in ethanol's reinforcing, subjective/discriminative stimulus, and relapse-inducing effects. The reinforcing properties of ethanol have been studied the most systematically, and convergent preclinical evidence suggests a key role for the α5 subunit in those effects. Regarding ethanol's subjective/discriminative stimulus effects, clinical and genetic findings support a primary role for the α2 subunit, whereas preclinical evidence implicates the α5 subunit. At present, too few studies investigating ethanol relapse exist to make any solid conclusions regarding the role of specific GABAA subunits in this abuse-related effect.
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Affiliation(s)
- Cassie M Chandler
- Graduate Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS, USA
| | - John S Overton
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, USA
| | - Daniela Rüedi-Bettschen
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, USA
| | - Donna M Platt
- Graduate Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS, USA.
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, USA.
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28
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Bowen MT, Neumann ID. Rebalancing the Addicted Brain: Oxytocin Interference with the Neural Substrates of Addiction. Trends Neurosci 2017; 40:691-708. [PMID: 29128108 DOI: 10.1016/j.tins.2017.10.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 10/05/2017] [Accepted: 10/06/2017] [Indexed: 12/21/2022]
Abstract
Drugs that act on the brain oxytocin (OXT) system may provide a much-needed treatment breakthrough for substance-use disorders. Targeting the brain OXT system has the potential to treat addiction to all major classes of addictive substance and to intervene across all stages of the addiction cycle. Emerging evidence suggests that OXT is able to interfere with such a wide range of addictive behaviours for such a wide range of addictive substances by rebalancing core neural systems that become dysregulated over the course of addiction. By improving our understanding of these interactions between OXT and the neural substrates of addiction, we will not only improve our understanding of addiction, but also our ability to effectively treat these devastating disorders.
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Affiliation(s)
- Michael T Bowen
- The University of Sydney, Faculty of Science, School of Psychology, Sydney, NSW, Australia; The University of Sydney, Brain and Mind Centre, Sydney, NSW, Australia
| | - Inga D Neumann
- Regensburg Center of Neuroscience, Department of Behavioural and Molecular Neurobiology, University of Regensburg, Regensburg, Germany.
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Millan EZ, Kim HA, Janak PH. Optogenetic activation of amygdala projections to nucleus accumbens can arrest conditioned and unconditioned alcohol consummatory behavior. Neuroscience 2017; 360:106-117. [PMID: 28757250 PMCID: PMC5752133 DOI: 10.1016/j.neuroscience.2017.07.044] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 07/13/2017] [Accepted: 07/19/2017] [Indexed: 11/25/2022]
Abstract
Following a Pavlovian pairing procedure, alcohol-paired cues come to elicit behavioral responses that lead to alcohol consumption. Here we used an optogenetic approach to activate basolateral amygdala (BLA) axonal terminals targeting the shell of nucleus accumbens (AcbSh) and investigated a possible influence over cue-conditioned alcohol seeking and alcohol drinking, based on the demonstrated roles of these areas in behavioral responding to Pavlovian cues and in feeding behavior. Rats were trained to anticipate alcohol or sucrose following the onset of a discrete conditioned stimulus (CS). Channelrhodopsin-mediated activation of the BLA-to-AcbSh pathway concurrent with each CS disrupted cued alcohol seeking. Activation of the same pathway caused rapid cessation of alcohol drinking from a sipper tube. Neither effect was accompanied by an overall change in locomotion. Finally, the suppressive effect of photoactivation on cued-triggered seeking was also evidenced in animals trained with sucrose. Together these findings suggest that photoactivation of BLA terminals in the AcbSh can override the conditioned motivational properties of reward-predictive cues as well as unconditioned consummatory responses necessary for alcohol drinking. The findings provide evidence for a limbic-striatal influence over motivated behavior for orally consumed rewards, including alcohol.
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Affiliation(s)
- E Zayra Millan
- Department of Psychological and Brain Sciences, Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore MD 21218, United States.
| | - H Amy Kim
- Department of Psychological and Brain Sciences, Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore MD 21218, United States
| | - Patricia H Janak
- Department of Psychological and Brain Sciences, Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore MD 21218, United States; Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore MD 21205, United States.
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Olsen RW, Liang J. Role of GABA A receptors in alcohol use disorders suggested by chronic intermittent ethanol (CIE) rodent model. Mol Brain 2017; 10:45. [PMID: 28931433 PMCID: PMC5605989 DOI: 10.1186/s13041-017-0325-8] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 09/05/2017] [Indexed: 11/10/2022] Open
Abstract
GABAergic inhibitory transmission is involved in the acute and chronic effects of ethanol on the brain and behavior. One-dose ethanol exposure induces transient plastic changes in GABAA receptor subunit levels, composition, and regional and subcellular localization. Rapid down-regulation of early responder δ subunit-containing GABAA receptor subtypes mediating ethanol-sensitive tonic inhibitory currents in critical neuronal circuits corresponds to rapid tolerance to ethanol's behavioral responses. Slightly slower, α1 subunit-containing GABAA receptor subtypes mediating ethanol-insensitive synaptic inhibition are down-regulated, corresponding to tolerance to additional ethanol behaviors plus cross-tolerance to other GABAergic drugs including benzodiazepines, anesthetics, and neurosteroids, especially sedative-hypnotic effects. Compensatory up-regulation of synaptically localized α4 and α2 subunit-containing GABAA receptor subtypes, mediating ethanol-sensitive synaptic inhibitory currents follow, but exhibit altered physio-pharmacology, seizure susceptibility, hyperexcitability, anxiety, and tolerance to GABAergic positive allosteric modulators, corresponding to heightened alcohol withdrawal syndrome. All these changes (behavioral, physiological, and biochemical) induced by ethanol administration are transient and return to normal in a few days. After chronic intermittent ethanol (CIE) treatment the same changes are observed but they become persistent after 30 or more doses, lasting for at least 120 days in the rat, and probably for life. We conclude that the ethanol-induced changes in GABAA receptors represent aberrant plasticity contributing critically to ethanol dependence and increased voluntary consumption. We suggest that the craving, drug-seeking, and increased consumption in the rat model are tied to ethanol-induced plastic changes in GABAA receptors, importantly the development of ethanol-sensitive synaptic GABAA receptor-mediating inhibitory currents that participate in maintained positive reward actions of ethanol on critical neuronal circuits. These probably disinhibit nerve endings of inhibitory GABAergic neurons on dopamine reward circuit cells, and limbic system circuits mediating anxiolysis in hippocampus and amygdala. We further suggest that the GABAA receptors contributing to alcohol dependence in the rat and presumably in human alcohol use disorders (AUD) are the ethanol-induced up-regulated subtypes containing α4 and most importantly α2 subunits. These mediate critical aspects of the positive reinforcement of ethanol in the dependent chronic user while alleviating heightened withdrawal symptoms experienced whenever ethanol is absent. The speculative conclusions based on firm observations are readily testable.
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Affiliation(s)
- Richard W. Olsen
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 USA
| | - Jing Liang
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095 USA
- Titus Family Department of Clinical Pharmacy, School of Pharmacy, University of Southern California, Los Angeles, CA 90089 USA
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31
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Melón LC, Nolan ZT, Colar D, Moore EM, Boehm SL. Activation of extrasynaptic δ-GABA A receptors globally or within the posterior-VTA has estrous-dependent effects on consumption of alcohol and estrous-independent effects on locomotion. Horm Behav 2017; 95:65-75. [PMID: 28765080 PMCID: PMC5623082 DOI: 10.1016/j.yhbeh.2017.07.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 07/26/2017] [Accepted: 07/26/2017] [Indexed: 11/21/2022]
Abstract
Recent reports support higher than expected rates of binge alcohol consumption among women and girls. Unfortunately, few studies have assessed the mechanisms underlying this pattern of intake in females. Studies in males suggest that alcohol concentrations relevant to the beginning stages of binge intoxication may selectively target tonic GABAergic inhibition mediated by GABAA receptor subtypes expressing the δ-subunit protein (δ-GABAARs). Indeed, administration of agonists that interact with these δ-GABAARs prior to alcohol access can abolish binge drinking behavior in male mice. These δ-GABAARs have also been shown to exhibit estrous-dependent plasticity in regions relevant to drug taking behavior, like the hippocampus and periaqueductal gray. The present experiments were designed to determine whether the estrous cycle would alter binge drinking, or our ability to modulate this pattern of alcohol use with THIP, an agonist with high selectivity and efficacy at δ-GABAARs. Using the Drinking-in-the-Dark (DID) binge-drinking model, regularly cycling female mice were given 2h of daily access to alcohol (20%v/v). Vaginal cytology or vaginal impedance was assessed after drinking sessions to track estrous status. There was no fluctuation in binge drinking associated with the estrous cycle. Both Intra-posterior-VTA administration of THIP and systemic administration of the drug was also associated with an estrous cycle dependent reduction in drinking behavior. Pre-treatment with finasteride to inhibit synthesis of 5α-reduced neurosteroids did not disrupt THIP's effects. Analysis of δ-subunit mRNA from posterior-VTA enriched tissue samples revealed that expression of this GABAA receptor subunit is elevated during diestrus in this region. Taken together, these studies demonstrate that δGABAARs in the VTA are an important target for binge drinking in females and confirm that the estrous cycle is an important moderator of the pharmacology of this GABAA receptor subtype.
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Affiliation(s)
- Laverne C Melón
- Addiction Neuroscience, Department of Psychology, Indiana University/Purdue University-Indianapolis, Indianapolis, IN 46202, USA; Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA
| | | | - Delphine Colar
- Addiction Neuroscience, Department of Psychology, Indiana University/Purdue University-Indianapolis, Indianapolis, IN 46202, USA
| | - Eileen M Moore
- Center for Behavioral Teratology, Department of Psychology, San Diego State University, San Diego, CA 92120, USA
| | - Stephen L Boehm
- Addiction Neuroscience, Department of Psychology, Indiana University/Purdue University-Indianapolis, Indianapolis, IN 46202, USA.
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32
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Effects of neonatal and adolescent neuroactive steroid manipulation on locomotor activity induced by ethanol in male wistar rats. Behav Brain Res 2017; 330:68-74. [DOI: 10.1016/j.bbr.2017.05.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 04/24/2017] [Accepted: 05/03/2017] [Indexed: 11/20/2022]
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Wright WJ, Dong Y. Tipping the Scales Toward Addiction. Biol Psychiatry 2017; 81:903-904. [PMID: 28502390 PMCID: PMC5792301 DOI: 10.1016/j.biopsych.2017.02.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Accepted: 02/13/2017] [Indexed: 12/23/2022]
Affiliation(s)
| | - Yan Dong
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania.
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Cheng Y, Huang CCY, Ma T, Wei X, Wang X, Lu J, Wang J. Distinct Synaptic Strengthening of the Striatal Direct and Indirect Pathways Drives Alcohol Consumption. Biol Psychiatry 2017; 81:918-929. [PMID: 27470168 PMCID: PMC5124556 DOI: 10.1016/j.biopsych.2016.05.016] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 05/20/2016] [Accepted: 05/23/2016] [Indexed: 12/14/2022]
Abstract
BACKGROUND Repeated exposure to addictive drugs or alcohol triggers glutamatergic and gamma-aminobutyric acidergic (GABAergic) plasticity in many neuronal populations. The dorsomedial striatum (DMS), a brain region critically involved in addiction, contains medium spiny neurons (MSNs) expressing dopamine D1 or D2 receptors, which form direct and indirect pathways, respectively. It is unclear how alcohol-evoked plasticity in the DMS contributes to alcohol consumption in a cell type-specific manner. METHODS Mice were trained to consume alcohol using an intermittent-access two-bottle-choice drinking procedure. Slice electrophysiology was used to measure glutamatergic and GABAergic strength in DMS D1- and D2-MSNs of alcohol-drinking mice and control mice. In vivo chemogenetic and pharmacologic approaches were employed to manipulate MSN activity, and their consequences on alcohol consumption were measured. RESULTS Repeated cycles of alcohol consumption and withdrawal in mice strengthened glutamatergic transmission in D1-MSNs and GABAergic transmission in D2-MSNs. In vivo chemogenetic excitation of D1-MSNs, mimicking glutamatergic strengthening, promoted alcohol consumption; the same effect was induced by D2-MSN inhibition, mimicking GABAergic strengthening. Importantly, suppression of GABAergic transmission via D2 receptor-glycogen synthase kinase-3β signaling dramatically reduced excessive alcohol consumption, as did selective inhibition of D1-MSNs or excitation of D2-MSNs. CONCLUSIONS Our results suggest that repeated cycles of excessive alcohol intake and withdrawal potentiate glutamatergic strength exclusively in D1-MSNs and GABAergic strength specifically in D2-MSNs of the DMS, which concurrently contribute to alcohol consumption. These results provide insight into the synaptic and cell type-specific mechanisms underlying alcohol addiction and identify targets for the development of new therapeutic approaches to alcohol abuse.
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Affiliation(s)
- Yifeng Cheng
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M Health Science Center, Bryan, Texas
| | - Cathy C Y Huang
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M Health Science Center, Bryan, Texas
| | - Tengfei Ma
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M Health Science Center, Bryan, Texas
| | - Xiaoyan Wei
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M Health Science Center, Bryan, Texas
| | - Xuehua Wang
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M Health Science Center, Bryan, Texas
| | - Jiayi Lu
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M Health Science Center, Bryan, Texas
| | - Jun Wang
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M Health Science Center, Bryan, Texas.
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Peters ST, Bowen MT, Bohrer K, McGregor IS, Neumann ID. Oxytocin inhibits ethanol consumption and ethanol-induced dopamine release in the nucleus accumbens. Addict Biol 2017; 22:702-711. [PMID: 26810371 DOI: 10.1111/adb.12362] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 12/04/2015] [Accepted: 12/07/2015] [Indexed: 11/29/2022]
Abstract
Alcohol (EtOH) is one of the most widely abused recreational drugs and is arguably the most harmful. However, current treatment options for alcohol-use disorders generally have limited efficacy and poor uptake in the community. In this context, the neuropeptide oxytocin (OXT) has emerged as a promising potential treatment option for a number of substance-use disorders, including alcoholism. The utility of OXT in reducing consumption of and craving for a wide range of substances may lie in its ability to modulate drug-induced neurochemical effects within the mesolimbic dopamine pathway. However, the impact of OXT on EtOH actions in this pathway has yet to be explored. Here, we reveal that an acute intracerebroventricular (icv) infusion of OXT (1 µg/5 µl) attenuated voluntary EtOH (20 percent) self-administration after chronic intermittent access to EtOH for 59 days (28 drinking sessions) in male Wistar rats. Next, we demonstrated that an acute intraperitoneal (ip) injection of EtOH (1.5 g/kg, 15 percent w/v) increased dopamine release within the nucleus accumbens in both EtOH-naive rats and rats that had received 10 daily ip injections of EtOH. Icv OXT completely blocked the EtOH-induced dopamine release in both EtOH-naive and chronically treated rats. The attenuation of EtOH-induced dopamine release by OXT may help to explain the reduced EtOH self-administration observed following icv OXT infusion.
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Affiliation(s)
- Sebastian T. Peters
- Department of Behavioral and Molecular Neurobiology; University of Regensburg; Germany
- Current address: Department of Neurology; University Clinic Regensburg; Germany
| | | | - Kathrin Bohrer
- Department of Behavioral and Molecular Neurobiology; University of Regensburg; Germany
| | | | - Inga D. Neumann
- Department of Behavioral and Molecular Neurobiology; University of Regensburg; Germany
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Lesscher HMB, Bailey A, Vanderschuren LJMJ. Genetic Variability in Adenosine Deaminase-Like Contributes to Variation in Alcohol Preference in Mice. Alcohol Clin Exp Res 2017; 41:1271-1279. [PMID: 28449374 DOI: 10.1111/acer.13409] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 04/20/2017] [Indexed: 11/29/2022]
Abstract
BACKGROUND A substantial part of the risk for alcohol use disorder is determined by genetic factors. We previously used chromosome substitution (CSS) mice, to identify a quantitative trait loci (QTL) for alcohol preference on mouse chromosome 2. The aim of this study was to identify candidate genes within this QTL that confer the risk for alcohol preference. METHODS In order to delineate the neurobiological underpinnings of alcohol consumption, we expanded on the QTL approach to identify candidate genes for high alcohol preference in mice. We narrowed down a QTL for alcohol preference on mouse chromosome 2, that we previously identified using CSS mice, to 4 candidate genes in silico. Expression levels of these candidate genes in prefrontal cortex, amygdala, and nucleus accumbens-brain regions implicated in reward and addiction-were subsequently compared for the CSS-2 and the C57BL/6J host strain. RESULTS We observed increased expression of adenosine deaminase-like (Adal) in all 3 regions in CSS-2 mice. Moreover, we found that the adenosine deaminase inhibitor EHNA reduced the difference in alcohol preference between CSS-2 and C57BL/6J mice. CONCLUSIONS This study identifies Adal as a genetically protective factor against alcohol consumption in mice, in which elevated Adal levels contribute to low alcohol preference.
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Affiliation(s)
- Heidi M B Lesscher
- Division of Behavioural Neuroscience , Department of Animals in Science and Society, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Alexis Bailey
- Institute of Medical and Biomedical Education , St George's University of London, London, UK
| | - Louk J M J Vanderschuren
- Division of Behavioural Neuroscience , Department of Animals in Science and Society, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
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Lovinger DM, Alvarez VA. Alcohol and basal ganglia circuitry: Animal models. Neuropharmacology 2017; 122:46-55. [PMID: 28341206 DOI: 10.1016/j.neuropharm.2017.03.023] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 03/16/2017] [Accepted: 03/20/2017] [Indexed: 01/18/2023]
Abstract
Brain circuits that include the cortex and basal ganglia make up the bulk of the forebrain, and influence behaviors related to almost all aspects of affective, cognitive and sensorimotor functions. The learning of new actions as well as association of existing action repertoires with environmental events are key functions of this circuitry. Unfortunately, the cortico-basal ganglia circuitry is also the target for all drugs of abuse, including alcohol. This makes the circuitry susceptible to the actions of chronic alcohol exposure that impairs circuit function in ways that contribute to cognitive dysfunction and drug use disorders. In the present review, we describe the connectivity and functions of the associative, limbic and sensorimotor cortico-basal ganglia circuits. We then review the effects of acute and chronic alcohol exposure on circuit function. Finally, we review studies examining the roles of the different circuits and circuit elements in alcohol use and abuse. We attempt to synthesize information from a variety of studies in laboratory animals and humans to generate hypotheses about how the three circuits interact with each other and with the other brain circuits during exposure to alcohol and during the development of alcohol use disorders. This article is part of the Special Issue entitled "Alcoholism".
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Affiliation(s)
- David M Lovinger
- Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, United States.
| | - Veronica A Alvarez
- Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, United States
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Bowen MT, Neumann ID. The Multidimensional Therapeutic Potential of Targeting the Brain Oxytocin System for the Treatment of Substance Use Disorders. Curr Top Behav Neurosci 2017; 35:269-287. [PMID: 28942596 DOI: 10.1007/7854_2017_17] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The neuropeptide oxytocin is released both into the blood and within the brain in response to reproductive stimuli, such as birth, suckling and sex, but also in response to social interaction and stressors. Substance use disorders, or addictions, are chronic, relapsing brain disorders and are one of the major causes of global burden of disease. Unfortunately, current treatment options for substance use disorders are extremely limited and a treatment breakthrough is sorely needed. There is mounting preclinical evidence that targeting the brain oxytocin system may provide that breakthrough. Substance use disorders are characterised by a viscous cycle of bingeing and intoxication, followed by withdrawal and negative affect, and finally preoccupation and anticipation that triggers relapse and further consumption. Administration of oxytocin has been shown to have a potential therapeutic benefit at each stage of this addiction cycle for numerous drugs of abuse. This multidimensional therapeutic utility is likely due to oxytocin's interactions with key biological systems that underlie the development and maintenance of addiction. Only a few human trials of oxytocin in addicted populations have been completed with the results thus far being mixed. There are numerous other trials underway, and the results are eagerly awaited. However, the ability to fully harness the potential therapeutic benefit of targeting the brain oxytocin system may depend on the development of molecules that selectively stimulate the oxytocin system, but that have superior pharmacokinetic properties to oxytocin itself.
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Affiliation(s)
- Michael T Bowen
- School of Psychology, Faculty of Science, University of Sydney, Sydney, NSW, Australia.,Brain and Mind Centre, University of Sydney, Sydney, NSW, Australia
| | - Inga D Neumann
- Department of Behavioural and Molecular Neurobiology, Regensburg Center of Neuroscience, University of Regensburg, 93053, Regensburg, Germany.
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Stephens DN, King SL, Lambert JJ, Belelli D, Duka T. GABAAreceptor subtype involvement in addictive behaviour. GENES BRAIN AND BEHAVIOR 2016; 16:149-184. [DOI: 10.1111/gbb.12321] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 07/19/2016] [Accepted: 08/15/2016] [Indexed: 12/17/2022]
Affiliation(s)
| | - S. L. King
- School of Psychology; University of Sussex; Brighton UK
| | - J. J. Lambert
- Division of Neuroscience; University of Dundee; Dundee UK
| | - D. Belelli
- Division of Neuroscience; University of Dundee; Dundee UK
| | - T. Duka
- School of Psychology; University of Sussex; Brighton UK
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40
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Fu R, Chen X, Zuo W, Li J, Kang S, Zhou LH, Siegel A, Bekker A, Ye JH. Ablation of μ opioid receptor-expressing GABA neurons in rostromedial tegmental nucleus increases ethanol consumption and regulates ethanol-related behaviors. Neuropharmacology 2016; 107:58-67. [PMID: 26921770 PMCID: PMC4912850 DOI: 10.1016/j.neuropharm.2016.02.027] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 02/19/2016] [Accepted: 02/22/2016] [Indexed: 01/02/2023]
Abstract
There has been increasing interest in the rostromedial tegmental nucleus (RMTg), given its potential regulatory role in many aversion-related behaviors. The RMTg contains mostly GABAergic neurons, sends a dense inhibitory projection to dopamine neurons in the midbrain, and is rich with μ-opioid receptors (MOR). Like most addictive drugs, ethanol has both aversive and rewarding properties. However, the cellular mechanisms underlying the effects of ethanol, particularly the aversive effect that limits its intake are not well understood. Recent studies have linked aversion with synaptic inhibition of dopamine neurons in the ventral tegmental area. To determine a potential role that the RMTg plays in the effect of ethanol, in this study, we employed a neurotoxin, dermorphin-saporin (DS), to lesion RMTg neurons prior to assessing ethanol-related behaviors. Rats were infused with DS bilaterally into the RMTg. This manipulation substantially increased the intake and preference for ethanol but not sucrose. It also reduced the number of neurons with MOR and glutamic acid decarboxylase 67 immunoreactivity within the RMTg. These changes did not occur after intra-RMTg infusion of blank saporin or vehicle. Importantly, intra-RMTg DS infusion significantly enhanced expression of conditioned place preference induced by ethanol (2 g/kg, i.p.), and slowed the extinction process. These results suggest that MOR-expressing GABAergic neurons in the RMTg contribute significantly to the regulation of ethanol consumption and related behaviors.
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Affiliation(s)
- Rao Fu
- Departments of Anesthesiology, Pharmacology and Physiology, (RF, XC, WZ, JL, SK, AB JHY), Psychiatry (AS) Rutgers-New Jersey Medical School, Newark, NJ, USA
| | - Xing Chen
- Departments of Anesthesiology, Pharmacology and Physiology, (RF, XC, WZ, JL, SK, AB JHY), Psychiatry (AS) Rutgers-New Jersey Medical School, Newark, NJ, USA
| | - Wanhong Zuo
- Departments of Anesthesiology, Pharmacology and Physiology, (RF, XC, WZ, JL, SK, AB JHY), Psychiatry (AS) Rutgers-New Jersey Medical School, Newark, NJ, USA
| | - Jing Li
- Departments of Anesthesiology, Pharmacology and Physiology, (RF, XC, WZ, JL, SK, AB JHY), Psychiatry (AS) Rutgers-New Jersey Medical School, Newark, NJ, USA
| | - Seungwoo Kang
- Departments of Anesthesiology, Pharmacology and Physiology, (RF, XC, WZ, JL, SK, AB JHY), Psychiatry (AS) Rutgers-New Jersey Medical School, Newark, NJ, USA
| | - Li-Hua Zhou
- Department of Anatomy, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China, (LHZ)
| | - Allan Siegel
- Departments of Anesthesiology, Pharmacology and Physiology, (RF, XC, WZ, JL, SK, AB JHY), Psychiatry (AS) Rutgers-New Jersey Medical School, Newark, NJ, USA
| | - Alex Bekker
- Departments of Anesthesiology, Pharmacology and Physiology, (RF, XC, WZ, JL, SK, AB JHY), Psychiatry (AS) Rutgers-New Jersey Medical School, Newark, NJ, USA
| | - Jiang-Hong Ye
- Departments of Anesthesiology, Pharmacology and Physiology, (RF, XC, WZ, JL, SK, AB JHY), Psychiatry (AS) Rutgers-New Jersey Medical School, Newark, NJ, USA.
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41
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Llidó A, Bartolomé I, Darbra S, Pallarès M. Effects of neonatal allopregnanolone manipulations and early maternal separation on adult alcohol intake and monoamine levels in ventral striatum of male rats. Horm Behav 2016; 82:11-20. [PMID: 27090561 DOI: 10.1016/j.yhbeh.2016.04.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 03/22/2016] [Accepted: 04/14/2016] [Indexed: 01/10/2023]
Abstract
Changes in endogenous neonatal levels of the neurosteroid allopregnanolone (AlloP) as well as a single 24h period of early maternal separation (EMS) on postnatal day (PND) 9 affect the development of the central nervous system (CNS), causing adolescent/adult alterations including systems and behavioural traits that could be related to vulnerability to drug abuse. In rats, some behavioural alterations caused by EMS can be neutralised by previous administration of AlloP. Thus, the aim of the present work is to analyse if manipulations of neonatal AlloP could increase adult alcohol consumption, and if EMS could change these effects. We administered AlloP or finasteride, a 5α-reductase inhibitor, from PND5 to PND9, followed by 24h of EMS at PND9. At PND70 we measured alcohol consumption using a two-bottle free-choice model (ethanol 10% (v/v)+glucose 3% (w/v), and glucose 3% (w/v)) for 15days. Ventral striatum samples were obtained to determine monoamine levels. Results revealed that neonatal finasteride increased both ethanol and glucose consumption, and AlloP increased alcohol intake compared with neonatal vehicle-injected animals. The differences between neonatal groups in alcohol consumption were not found in EMS animals. In accordance, both finasteride and AlloP animals that did not suffer EMS showed lower levels of dopamine and serotonin in ventral striatum. Taken together, these results reveal that neonatal neurosteroids alterations affect alcohol intake; an effect which can be modified by subsequent EMS. Thus, these data corroborate the importance of the relationship between neonatal neurosteroids and neonatal stress for the correct CNS development.
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Affiliation(s)
- Anna Llidó
- Departament de Psicobiologia i Metodologia de les Ciències de la Salut, Institut de Neurociències, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain
| | - Iris Bartolomé
- Departament de Psicobiologia i Metodologia de les Ciències de la Salut, Institut de Neurociències, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain
| | - Sònia Darbra
- Departament de Psicobiologia i Metodologia de les Ciències de la Salut, Institut de Neurociències, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain
| | - Marc Pallarès
- Departament de Psicobiologia i Metodologia de les Ciències de la Salut, Institut de Neurociències, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain.
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42
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Förstera B, Castro PA, Moraga-Cid G, Aguayo LG. Potentiation of Gamma Aminobutyric Acid Receptors (GABAAR) by Ethanol: How Are Inhibitory Receptors Affected? Front Cell Neurosci 2016; 10:114. [PMID: 27199667 PMCID: PMC4858537 DOI: 10.3389/fncel.2016.00114] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 04/20/2016] [Indexed: 01/10/2023] Open
Abstract
In recent years there has been an increase in the understanding of ethanol actions on the type A γ-aminobutyric acid chloride channel (GABAAR), a member of the pentameric ligand gated ion channels (pLGICs). However, the mechanism by which ethanol potentiates the complex is still not fully understood and a number of publications have shown contradictory results. Thus many questions still remain unresolved requiring further studies for a better comprehension of this effect. The present review concentrates on the involvement of GABAAR in the acute actions of ethanol and specifically focuses on the immediate, direct or indirect, synaptic and extra-synaptic modulatory effects. To elaborate on the immediate, direct modulation of GABAAR by acute ethanol exposure, electrophysiological studies investigating the importance of different subunits, and data from receptor mutants will be examined. We will also discuss the nature of the putative binding sites for ethanol based on structural data obtained from other members of the pLGICs family. Finally, we will briefly highlight the glycine gated chloride channel (GlyR), another member of the pLGIC family, as a suitable target for the development of new pharmacological tools.
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Affiliation(s)
- Benjamin Förstera
- Laboratory of Neurophysiology, Department of Physiology, University of Concepcion Concepcion, Chile
| | - Patricio A Castro
- Laboratory of Environmental Neurotoxicology, Department of Biomedical Sciences, Faculty of Medicine, Universidad Católica del Norte Coquimbo, Chile
| | - Gustavo Moraga-Cid
- Hindbrain Integrative Neurobiology Laboratory, Institut de Neurobiologie Alfred Fessard Gif-Sur-Yvette, France
| | - Luis G Aguayo
- Laboratory of Neurophysiology, Department of Physiology, University of Concepcion Concepcion, Chile
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43
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Quoilin C, Boehm SL. Involvement of the GABAA Receptor in Age-Dependent Differences in Binge-Like Ethanol Intake. Alcohol Clin Exp Res 2016; 40:408-17. [PMID: 26833274 DOI: 10.1111/acer.12953] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 11/04/2015] [Indexed: 11/27/2022]
Abstract
BACKGROUND Binge alcohol (ethanol [EtOH]) drinking is common during adolescence, a time characterized by many behavioral and neurobiological changes. Among them, the GABAA receptor system undergoes substantial modifications, including changes in the density, distribution, and subunit composition of the receptor. Based on its demonstrated role in EtOH consumption, this study aimed to investigate the effects of 2 different GABAA receptor agonists on binge-like EtOH intake in adolescent and adult mice using the Drinking-in-the-Dark model. METHODS Three hours into their dark cycle, adolescent (postnatal day 28 [P28]) and adult (P63) male C57BL/6J mice were given daily access to 20% EtOH for 2 hours during 8 consecutive days. Immediately before the access on day 8, mice (P35 and P70) were systemically injected with 1 of 2 different GABAergic drugs. The effects of muscimol, a full GABAA agonist, were assessed in a first experiment. The second experiment tested for the more specific involvement of δ-containing extrasynaptic GABAA receptors through the administration of THIP (4,5,6,7-tetrahydroisoxazolo(5,4-c)pyridin-3-ol). RESULTS Adolescent mice consumed more EtOH than their adult counterparts. Following the administration of GABAA agonists, levels of EtOH intake were reduced at both ages. However, age-dependent differences were revealed following the administration of THIP, with adolescents exhibiting greater sensitivity to its suppressant effects, especially during the first 30 minutes of binge EtOH access. CONCLUSIONS This study adds to the existing literature demonstrating the crucial role of the GABAA receptor in alcohol consumption. In addition, it suggests that age differences in the GABAA receptor modulation of binge alcohol drinking might be more dependent on extrasynaptic GABAA receptors.
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Affiliation(s)
- Caroline Quoilin
- Addiction Neuroscience, Department of Psychology, Indiana University - Purdue University Indianapolis, Indianapolis, Indiana
| | - Stephen L Boehm
- Addiction Neuroscience, Department of Psychology, Indiana University - Purdue University Indianapolis, Indianapolis, Indiana
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Mayfield J, Arends MA, Harris RA, Blednov YA. Genes and Alcohol Consumption: Studies with Mutant Mice. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2016; 126:293-355. [PMID: 27055617 PMCID: PMC5302130 DOI: 10.1016/bs.irn.2016.02.014] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In this chapter, we review the effects of global null mutant and overexpressing transgenic mouse lines on voluntary self-administration of alcohol. We examine approximately 200 publications pertaining to the effects of 155 mouse genes on alcohol consumption in different drinking models. The targeted genes vary in function and include neurotransmitter, ion channel, neuroimmune, and neuropeptide signaling systems. The alcohol self-administration models include operant conditioning, two- and four-bottle choice continuous and intermittent access, drinking in the dark limited access, chronic intermittent ethanol, and scheduled high alcohol consumption tests. Comparisons of different drinking models using the same mutant mice are potentially the most informative, and we will highlight those examples. More mutants have been tested for continuous two-bottle choice consumption than any other test; of the 137 mouse genes examined using this model, 97 (72%) altered drinking in at least one sex. Overall, the effects of genetic manipulations on alcohol drinking often depend on the sex of the mice, alcohol concentration and time of access, genetic background, as well as the drinking test.
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Affiliation(s)
- J Mayfield
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, United States
| | - M A Arends
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA, United States
| | - R A Harris
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, United States.
| | - Y A Blednov
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, United States
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Cigarettes and alcohol: The influence of nicotine on operant alcohol self-administration and the mesolimbic dopamine system. Biochem Pharmacol 2015; 97:550-557. [PMID: 26253689 DOI: 10.1016/j.bcp.2015.07.038] [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: 06/26/2015] [Accepted: 07/30/2015] [Indexed: 12/11/2022]
Abstract
Studies in human populations consistently demonstrate an interaction between nicotine and ethanol use, each drug influencing the use of the other. Here we present data and review evidence from animal studies that nicotine influences operant self-administration of ethanol. The operant reinforcement paradigm has proven to be a behaviorally relevant and quantitative model for studying ethanol-seeking behavior. Exposure to nicotine can modify the reinforcing properties of ethanol during different phases of ethanol self-administration, including acquisition, maintenance, and reinstatement. Our data suggest that non-daily intermittent nicotine exposure can trigger a long-lasting increase in ethanol self-administration. The biological basis for interactions between nicotine and ethanol is not well understood but may involve the stress hormone systems and adaptations in the mesolimbic dopamine system. Future studies that combine operant self-administration with techniques for monitoring or manipulating in vivo neurophysiology may provide new insights into the neuronal mechanisms that link nicotine and alcohol use.
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46
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Prosser RA, Glass JD. Assessing ethanol's actions in the suprachiasmatic circadian clock using in vivo and in vitro approaches. Alcohol 2015; 49:321-339. [PMID: 25457753 DOI: 10.1016/j.alcohol.2014.07.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 07/07/2014] [Accepted: 07/09/2014] [Indexed: 12/18/2022]
Abstract
Research over the past decade has demonstrated substantial interactions between the circadian system and the processes through which alcohol affects behavior and physiology. Here we summarize the results of our collaborative efforts focused on this intersection. Using a combination of in vivo and in vitro approaches, we have shown that ethanol affects many aspects of the mammalian circadian system, both acutely as well as after chronic administration. Conversely, we have shown circadian influences on ethanol consumption. Importantly, we are beginning to delve into the cellular mechanisms associated with these effects. We are also starting to form a picture of the neuroanatomical bases for many of these actions. Finally, we put our current findings into perspective by suggesting new avenues of inquiry for our future efforts.
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47
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Ramaker MJ, Strong-Kaufman MN, Ford MM, Phillips TJ, Finn DA. Effect of nucleus accumbens shell infusions of ganaxolone or gaboxadol on ethanol consumption in mice. Psychopharmacology (Berl) 2015; 232:1415-26. [PMID: 25342197 PMCID: PMC4412309 DOI: 10.1007/s00213-014-3777-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 10/10/2014] [Indexed: 01/16/2023]
Abstract
RATIONALE Allopregnanolone (ALLO) is an endogenous neuroactive steroid thought to alter the reinforcement value of alcohol (ethanol) due to its actions as a positive modulator of the GABAA receptor (GABAAR). Extrasynaptic GABAARs may be a particularly sensitive target of ethanol and neuroactive steroids. Previous work showed that systemic injections of an ALLO analog, ganaxolone (GAN), or an extrasynaptic GABAAR agonist (gaboxadol; THIP) decreased ethanol intake in male mice with limited access to ethanol. OBJECTIVES The present studies tested whether activation of GABAARs in the nucleus accumbens (NAc) shell by GAN or THIP was sufficient to reduce ethanol intake. C57BL/6J male mice had 2-h access to 10 % ethanol (10E) and water, and 10E intake was measured following site-specific infusions of GAN or THIP. RESULTS Decreases in limited-access 10E consumption were observed following site-specific bilateral infusions of either drug into the NAc shell. Significant changes in intake were absent when the drugs were infused in a region dorsal to the target site (GAN) or into the lateral ventricle (THIP). Locomotor data confirmed that the decreases in intake were not due to a sedative effect of the drugs. CONCLUSIONS These data demonstrate the sufficiency of GABAAR activation by a positive allosteric modulator or an agonist with selectivity for extrasynaptic GABAARs to decrease ethanol consumption in mice. Importantly, more refined GABAAR-active targets that decrease ethanol intake may enhance our understanding and ability to treat alcohol use disorders.
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Affiliation(s)
- Marcia J. Ramaker
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239
| | | | - Matthew M. Ford
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239
| | - Tamara J. Phillips
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239,Department of Veterans Affairs Medical Research, Portland, OR 97239
| | - Deborah A. Finn
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239,Department of Veterans Affairs Medical Research, Portland, OR 97239
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Oxytocin prevents ethanol actions at δ subunit-containing GABAA receptors and attenuates ethanol-induced motor impairment in rats. Proc Natl Acad Sci U S A 2015; 112:3104-9. [PMID: 25713389 DOI: 10.1073/pnas.1416900112] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Even moderate doses of alcohol cause considerable impairment of motor coordination, an effect that substantially involves potentiation of GABAergic activity at δ subunit-containing GABA(A) receptors (δ-GABA(A)Rs). Here, we demonstrate that oxytocin selectively attenuates ethanol-induced motor impairment and ethanol-induced increases in GABAergic activity at δ-GABA(A)Rs and that this effect does not involve the oxytocin receptor. Specifically, oxytocin (1 µg i.c.v.) given before ethanol (1.5 g/kg i.p.) attenuated the sedation and ataxia induced by ethanol in the open-field locomotor test, wire-hanging test, and righting-reflex test in male rats. Using two-electrode voltage-clamp electrophysiology in Xenopus oocytes, oxytocin was found to completely block ethanol-enhanced activity at α4β1δ and α4β3δ recombinant GABA(A)Rs. Conversely, ethanol had no effect when applied to α4β1 or α4β3 cells, demonstrating the critical presence of the δ subunit in this effect. Oxytocin had no effect on the motor impairment or in vitro effects induced by the δ-selective GABA(A)R agonist 4,5,6,7-tetrahydroisoxazolo(5,4-c)pyridin-3-ol, which binds at a different site on δ-GABA(A)Rs than ethanol. Vasopressin, which is a nonapeptide with substantial structural similarity to oxytocin, did not alter ethanol effects at δ-GABA(A)Rs. This pattern of results confirms the specificity of the interaction between oxytocin and ethanol at δ-GABA(A)Rs. Finally, our in vitro constructs did not express any oxytocin receptors, meaning that the observed interactions occur directly at δ-GABA(A)Rs. The profound and direct interaction observed between oxytocin and ethanol at the behavioral and cellular level may have relevance for the development of novel therapeutics for alcohol intoxication and dependence.
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Olsen RW. Allosteric ligands and their binding sites define γ-aminobutyric acid (GABA) type A receptor subtypes. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2015; 73:167-202. [PMID: 25637441 DOI: 10.1016/bs.apha.2014.11.005] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
GABAA receptors (GABA(A)Rs) mediate rapid inhibitory transmission in the brain. GABA(A)Rs are ligand-gated chloride ion channel proteins and exist in about a dozen or more heteropentameric subtypes exhibiting variable age and brain regional localization and thus participation in differing brain functions and diseases. GABA(A)Rs are also subject to modulation by several chemotypes of allosteric ligands that help define structure and function, including subtype definition. The channel blocker picrotoxin identified a noncompetitive channel blocker site in GABA(A)Rs. This ligand site is located in the transmembrane channel pore, whereas the GABA agonist site is in the extracellular domain at subunit interfaces, a site useful for low energy coupled conformational changes of the functional channel domain. Two classes of pharmacologically important allosteric modulatory ligand binding sites reside in the extracellular domain at modified agonist sites at other subunit interfaces: the benzodiazepine site and the high-affinity, relevant to intoxication, ethanol site. The benzodiazepine site is specific for certain GABA(A)R subtypes, mainly synaptic, while the ethanol site is found at a modified benzodiazepine site on different, extrasynaptic, subtypes. In the transmembrane domain are allosteric modulatory ligand sites for diverse chemotypes of general anesthetics: the volatile and intravenous agents, barbiturates, etomidate, propofol, long-chain alcohols, and neurosteroids. The last are endogenous positive allosteric modulators. X-ray crystal structures of prokaryotic and invertebrate pentameric ligand-gated ion channels, and the mammalian GABA(A)R protein, allow homology modeling of GABA(A)R subtypes with the various ligand sites located to suggest the structure and function of these proteins and their pharmacological modulation.
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Affiliation(s)
- Richard W Olsen
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.
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Lovinger DM. Mechanisms of Neuroplasticity and Ethanol's Effects on Plasticity in the Striatum and Bed Nucleus of the Stria Terminalis. Alcohol Res 2015; 37:109-24. [PMID: 26259092 PMCID: PMC4476598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Long-lasting changes in synaptic function (i.e., synaptic plasticity) have long been thought to contribute to information storage in the nervous system. Although synaptic plasticity mainly has adaptive functions that allow the organism to function in complex environments, it is now clear that certain events or exposure to various substances can produce plasticity that has negative consequences for organisms. Exposure to drugs of abuse, in particular ethanol, is a life experience that can activate or alter synaptic plasticity, often resulting in increased drug seeking and taking and in many cases addiction.Two brain regions subject to alcohol's effects on synaptic plasticity are the striatum and bed nucleus of the stria terminalis (BNST), both of which have key roles in alcohol's actions and control of intake. The specific effects depend on both the brain region analyzed (e.g., specific subregions of the striatum and BNST) and the duration of ethanol exposure (i.e., acute vs. chronic). Plastic changes in synaptic transmission in these two brain regions following prolonged ethanol exposure are thought to contribute to excessive alcohol drinking and relapse to drinking. Understanding the mechanisms underlying this plasticity may lead to new therapies for treatment of these and other aspects of alcohol use disorder.
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