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Nicholas CR, Banks MI, Lennertz RC, Wenthur CJ, Krause BM, Riedner BA, Smith RF, Hutson PR, Sauder CJ, Dunne JD, Roseman L, Raison CL. Co-administration of midazolam and psilocybin: differential effects on subjective quality versus memory of the psychedelic experience. Transl Psychiatry 2024; 14:372. [PMID: 39266503 PMCID: PMC11393325 DOI: 10.1038/s41398-024-03059-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 08/19/2024] [Accepted: 08/22/2024] [Indexed: 09/14/2024] Open
Abstract
Aspects of the acute experience induced by the serotonergic psychedelic psilocybin predict symptomatic relief in multiple psychiatric disorders and improved well-being in healthy participants, but whether these therapeutic effects are immediate or are based on memories of the experience is unclear. To examine this, we co-administered psilocybin (25 mg) with the amnestic benzodiazepine midazolam in 8 healthy participants and assayed the subjective quality of, and memory for, the dosing-day experience. We identified a midazolam dose that allowed a conscious psychedelic experience to occur while partially impairing memory for the experience. Furthermore, midazolam dose and memory impairment tended to associate inversely with salience, insight, and well-being induced by psilocybin. These data suggest a role for memory in therapeutically relevant behavioral effects occasioned by psilocybin. Because midazolam blocks memory by blocking cortical neural plasticity, it may also be useful for evaluating the contribution of the pro-neuroplastic properties of psychedelics to their therapeutic activity.
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Affiliation(s)
- Christopher R Nicholas
- Department of Family Medicine and Community Health, School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53706, USA
- Transdisciplinary Center for Research in Psychoactive Substances, University of Wisconsin, Madison, WI, 53705, USA
| | - Matthew I Banks
- Transdisciplinary Center for Research in Psychoactive Substances, University of Wisconsin, Madison, WI, 53705, USA.
- Department of Anesthesiology, School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53706, USA.
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53706, USA.
| | - Richard C Lennertz
- Transdisciplinary Center for Research in Psychoactive Substances, University of Wisconsin, Madison, WI, 53705, USA
- Department of Anesthesiology, School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53706, USA
| | - Cody J Wenthur
- Transdisciplinary Center for Research in Psychoactive Substances, University of Wisconsin, Madison, WI, 53705, USA
- School of Pharmacy, University of Wisconsin, Madison, WI, 53705, USA
| | - Bryan M Krause
- Department of Anesthesiology, School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53706, USA
| | - Brady A Riedner
- Department of Psychiatry, School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53706, USA
- Wisconsin Institute for Sleep and Consciousness, University of Wisconsin, Madison, WI, 53706, USA
| | - Richard F Smith
- Department of Psychiatry, School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53706, USA
- Wisconsin Institute for Sleep and Consciousness, University of Wisconsin, Madison, WI, 53706, USA
| | - Paul R Hutson
- Transdisciplinary Center for Research in Psychoactive Substances, University of Wisconsin, Madison, WI, 53705, USA
- School of Pharmacy, University of Wisconsin, Madison, WI, 53705, USA
| | - Christina J Sauder
- Department of Psychiatry, School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53706, USA
| | - John D Dunne
- Transdisciplinary Center for Research in Psychoactive Substances, University of Wisconsin, Madison, WI, 53705, USA
- Center for Healthy Minds, University of Wisconsin-Madison, Madison, WI, 53706, USA
- Department of Asian Languages and Cultures, University of Wisconsin-Madison, Madison, WI, 53726, USA
| | - Leor Roseman
- Department of Psychology, University of Exeter, Exeter, UK
- Centre for Psychedelic Research, Imperial College London, London, UK
| | - Charles L Raison
- Transdisciplinary Center for Research in Psychoactive Substances, University of Wisconsin, Madison, WI, 53705, USA.
- Department of Psychiatry, School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53706, USA.
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2
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Cardona-Acosta AM, Meisser N, Vardeleon NI, Steiner H, Bolaños-Guzmán CA. Mother's little helper turned a foe: Alprazolam use, misuse, and abuse. Prog Neuropsychopharmacol Biol Psychiatry 2024; 136:111137. [PMID: 39260815 DOI: 10.1016/j.pnpbp.2024.111137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 08/27/2024] [Accepted: 09/04/2024] [Indexed: 09/13/2024]
Abstract
Benzodiazepines are effective in managing anxiety and related disorders when used properly (short-term). Their inappropriate use, however, carries significant risks, involving amnesia, rebound insomnia, rebound anxiety, depression, dependence, abuse, addiction, and an intense and exceedingly prolonged withdrawal, among other complications. Benzodiazepines also amplify the effects of opioids and, consequently, have been implicated in approximately 30 % of opioid overdose deaths. Despite their unfavorable profile, sharp increases in medical and non-medical use of benzodiazepines have been steadily reported worldwide. Alprazolam (Xanax®), a potent, short-acting benzodiazepine, is among the most prescribed and abused anxiolytics in the United States. This medication is commonly co-abused with opioids, increasing the likelihood for oversedation, overdose, and death. Notwithstanding these risks, it is surprising that research investigating how benzodiazepines, such as alprazolam, interact with opioids is severely lacking in clinical and preclinical settings. This review therefore aims to present our current knowledge of benzodiazepine use and misuse, with an emphasis on alprazolam when data is available, and particularly in populations at higher risk for developing substance use disorders. Additionally, the potential mechanism(s) surrounding tolerance, dependence and abuse liability are discussed. Despite their popularity, our understanding of how benzodiazepines and opioids interact is less than adequate. Therefore, it is now more important than ever to understand the short- and long-term consequences of benzodiazepine/alprazolam use.
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Affiliation(s)
- Astrid M Cardona-Acosta
- Department of Psychological and Brain Sciences, and Institute for Neuroscience, Texas A&M University, College Station, TX 77843, USA
| | - Noelle Meisser
- Department of Psychological and Brain Sciences, and Institute for Neuroscience, Texas A&M University, College Station, TX 77843, USA
| | - Nathan I Vardeleon
- Department of Psychological and Brain Sciences, and Institute for Neuroscience, Texas A&M University, College Station, TX 77843, USA
| | - Heinz Steiner
- Stanson Toshok Center for Brain Function and Repair, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA; Discipline of Cellular and Molecular Pharmacology, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
| | - Carlos A Bolaños-Guzmán
- Department of Psychological and Brain Sciences, and Institute for Neuroscience, Texas A&M University, College Station, TX 77843, USA.
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3
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Moraru MV, Stoleru S, Zugravu A, Coman OA, Fulga I. New Insights Into Pharmacology of GABAA Receptor Alpha Subunits-Selective Modulators. Am J Ther 2024:00045391-990000000-00218. [PMID: 39240716 DOI: 10.1097/mjt.0000000000001810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/08/2024]
Abstract
BACKGROUND Benzodiazepines have long held a leading position in medical therapeutics, known for their multiple common therapeutic properties and primarily being prescribed for anxiety and insomnia. However, their lack of specificity and various side effects have led to a reevaluation of their long-term use, resulting in a rapid growth in the literature focusing on targeted therapies. AREAS OF UNCERTAINTY Despite many efforts, uncertainties persist and there are heterogeneous findings across studies regarding the pharmacological effects attributed to gamma-aminobutyric acid type A (GABAA) receptor subunits. Selective compounds targeting GABAA receptor alpha subunits are currently under active research and definitive conclusions have not been reached yet. Some compounds have not progressed to clinical trials, while others, if advanced, have been halted. These challenges emphasize the difficulty in translating preclinical findings into clinical use. DATA SOURCES A literature review was conducted using the PubMed database, searching for articles discussing GABAA receptor subunits. The search was refined by including only selective compounds with potential anxiolytic and cognitive enhancement properties. RESULTS Findings reveal compounds with promising anxiolytic and antidepressant effects with minimal sedation and absence of tolerance development. Moreover, some compounds show potential in alleviating cognitive dysfunction. There is a broad spectrum of potential therapeutic applications for selective compounds, ranging from neurological disorders such as epilepsy and neuropathic pain to cognitive dysfunction-related conditions. Currently, the leading selective compounds with the most promising results in ongoing clinical trials are basmisanil and darigabat. Basmisanil holds further exploration potential in the treatment of cognitive impairment and related conditions, while darigabat shows progress in the advancement of adjunctive therapy of focal onset seizures and for the treatment of panic disorder, respectively. CONCLUSIONS Future drug discovery efforts are encouraged to focus on positive allosteric modulators that selectively target the α2, α3 subunits and negative/positive allosteric modulators that target the α5 subunit of the GABAA receptor. The pursuit of ligands possessing only anxiolytic effects or those enhancing cognition continues to be an important focus for future research, with promising advancements depicted in recent studies.
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Lorenz-Guertin JM, Povysheva N, Chapman CA, MacDonald ML, Fazzari M, Nigam A, Nuwer JL, Das S, Brady ML, Vajn K, Bambino MJ, Weintraub ST, Johnson JW, Jacob TC. Inhibitory and excitatory synaptic neuroadaptations in the diazepam tolerant brain. Neurobiol Dis 2023; 185:106248. [PMID: 37536384 PMCID: PMC10578451 DOI: 10.1016/j.nbd.2023.106248] [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: 05/12/2023] [Revised: 07/20/2023] [Accepted: 07/31/2023] [Indexed: 08/05/2023] Open
Abstract
Benzodiazepine (BZ) drugs treat seizures, anxiety, insomnia, and alcohol withdrawal by potentiating γ2 subunit containing GABA type A receptors (GABAARs). BZ clinical use is hampered by tolerance and withdrawal symptoms including heightened seizure susceptibility, panic, and sleep disturbances. Here, we investigated inhibitory GABAergic and excitatory glutamatergic plasticity in mice tolerant to benzodiazepine sedation. Repeated diazepam (DZP) treatment diminished sedative effects and decreased DZP potentiation of GABAAR synaptic currents without impacting overall synaptic inhibition. While DZP did not alter γ2-GABAAR subunit composition, there was a redistribution of extrasynaptic GABAARs to synapses, resulting in higher levels of synaptic BZ-insensitive α4-containing GABAARs and a concomitant reduction in tonic inhibition. Conversely, excitatory glutamatergic synaptic transmission was increased, and NMDAR subunits were upregulated at synaptic and total protein levels. Quantitative proteomics further revealed cortex neuroadaptations of key pro-excitatory mediators and synaptic plasticity pathways highlighted by Ca2+/calmodulin-dependent protein kinase II (CAMKII), MAPK, and PKC signaling. Thus, reduced inhibitory GABAergic tone and elevated glutamatergic neurotransmission contribute to disrupted excitation/inhibition balance and reduced BZ therapeutic power with benzodiazepine tolerance.
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Affiliation(s)
- Joshua M Lorenz-Guertin
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Nadya Povysheva
- Department of Neuroscience and Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
| | - Caitlyn A Chapman
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Matthew L MacDonald
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Marco Fazzari
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Aparna Nigam
- Department of Neuroscience and Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jessica L Nuwer
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Sabyasachi Das
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Megan L Brady
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Katarina Vajn
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Matthew J Bambino
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Susan T Weintraub
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antoni, TX, USA
| | - Jon W Johnson
- Department of Neuroscience and Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
| | - Tija C Jacob
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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Cardona-Acosta AM, Sial OK, Parise LF, Gnecco T, Enriquez Marti G, Bolaños-Guzmán CA. Alprazolam exposure during adolescence induces long-lasting dysregulation in reward sensitivity to morphine and second messenger signaling in the VTA-NAc pathway. Sci Rep 2023; 13:10872. [PMID: 37407659 DOI: 10.1038/s41598-023-37696-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 06/26/2023] [Indexed: 07/07/2023] Open
Abstract
Increased use of benzodiazepines in adolescents have been reported, with alprazolam (ALP) being the most abused. Drug abuse during adolescence can induce changes with lasting consequences. This study investigated the neurobiological consequences of ALP exposure during adolescence in C57BL/6J male mice. Mice received ALP (0, 0.5, 1.0 mg/kg) once/daily (postnatal day 35-49). Changes in responsiveness to morphine (2.5, 5.0 mg/kg), using the conditioned place preference paradigm, were assessed 24-h and 1-month after ALP exposure. In a separate experiment, mice received ALP (0, 0.5 mg/kg) and then sacrificed 24-h or 1-month after treatment to assess levels of extracellular signal regulated kinase 1/2 (ERK1/2) gene expression, protein phosphorylation, and downstream targets (CREB, AKT) within the ventral tegmental area (VTA) and nucleus accumbens (NAc). ALP-pretreated mice developed a strong preference to the compartment(s) paired with a subthreshold dose (2.5 mg/kg) of MOR short-term, and this effect was also present in the 1-month group. Adolescent ALP exposure resulted in dysregulation of ERK-signaling within the VTA-NAc pathway 24-h and 1-month after ALP exposure. Results indicate ALP exposure during adolescence potentiates the rewarding properties of MOR and induces persistent changes in ERK-signaling within the VTA-NAc pathway, a brain circuit highly implicated in the regulation of both drug reward and mood- related behaviors.
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Affiliation(s)
- Astrid M Cardona-Acosta
- Department of Psychological and Brain Sciences and Program in Neuroscience, Texas A&M University, College Station, TX, 77843, USA
| | - Omar K Sial
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL, USA
| | - Lyonna F Parise
- Fishberg Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Tamara Gnecco
- Department of Psychological and Brain Sciences and Program in Neuroscience, Texas A&M University, College Station, TX, 77843, USA
| | - Giselle Enriquez Marti
- Department of Psychological and Brain Sciences and Program in Neuroscience, Texas A&M University, College Station, TX, 77843, USA
| | - Carlos A Bolaños-Guzmán
- Department of Psychological and Brain Sciences and Program in Neuroscience, Texas A&M University, College Station, TX, 77843, USA.
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Cai J, Tong Q. Anatomy and Function of Ventral Tegmental Area Glutamate Neurons. Front Neural Circuits 2022; 16:867053. [PMID: 35669454 PMCID: PMC9164627 DOI: 10.3389/fncir.2022.867053] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 03/30/2022] [Indexed: 11/29/2022] Open
Abstract
The ventral tegmental area (VTA) is well known for regulating reward consumption, learning, memory, and addiction behaviors through mediating dopamine (DA) release in downstream regions. Other than DA neurons, the VTA is known to be heterogeneous and contains other types of neurons, including glutamate neurons. In contrast to the well-studied and established functions of DA neurons, the role of VTA glutamate neurons is understudied, presumably due to their relatively small quantity and a lack of effective means to study them. Yet, emerging studies have begun to reveal the importance of glutamate release from VTA neurons in regulating diverse behavioral repertoire through a complex intra-VTA and long-range neuronal network. In this review, we summarize the features of VTA glutamate neurons from three perspectives, namely, cellular properties, neural connections, and behavioral functions. Delineation of VTA glutamatergic pathways and their interactions with VTA DA neurons in regulating behaviors may reveal previously unappreciated functions of the VTA in other physiological processes.
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Affiliation(s)
- Jing Cai
- Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, UTHealth McGovern Medical School, Houston, TX, United States
- Neuroscience Program, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States
| | - Qingchun Tong
- Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, UTHealth McGovern Medical School, Houston, TX, United States
- Neuroscience Program, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States
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7
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Engin E. GABA A receptor subtypes and benzodiazepine use, misuse, and abuse. Front Psychiatry 2022; 13:1060949. [PMID: 36713896 PMCID: PMC9879605 DOI: 10.3389/fpsyt.2022.1060949] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 12/29/2022] [Indexed: 01/14/2023] Open
Abstract
Benzodiazepines have been in use for over half a century. While they remain highly prescribed, their unfavorable side-effect profile and abuse liability motivated a search for alternatives. Most of these efforts focused on the development of benzodiazepine-like drugs that are selective for specific GABAA receptor subtypes. While there is ample evidence that subtype-selective GABAA receptor ligands have great potential for providing symptom relief without typical benzodiazepine side-effects, it is less clear whether subtype-selective targeting strategies can also reduce misuse and abuse potential. This review focuses on the three benzodiazepine properties that are relevant to the DSM-5-TR criteria for Sedative, Hypnotic, or Anxiolytic Use Disorder, namely, reinforcing properties of benzodiazepines, maladaptive behaviors related to benzodiazepine use, and benzodiazepine tolerance and dependence. We review existing evidence regarding the involvement of different GABAA receptor subtypes in each of these areas. The reviewed studies suggest that α1-containing GABAA receptors play an integral role in benzodiazepine-induced plasticity in reward-related brain areas and might be involved in the development of tolerance and dependence to benzodiazepines. However, a systematic comparison of the contributions of all benzodiazepine-sensitive GABAA receptors to these processes, a mechanistic understanding of how the positive modulation of each receptor subtype might contribute to the brain mechanisms underlying each of these processes, and a definitive answer to the question of whether specific chronic modulation of any given subtype would result in some or all of the benzodiazepine effects are currently lacking from the literature. Moreover, how non-selective benzodiazepines might lead to the maladaptive behaviors listed in DSM and how different GABAA receptor subtypes might be involved in the development of these behaviors remains unexplored. Considering the increasing burden of benzodiazepine abuse, the common practice of benzodiazepine misuse that leads to severe dependence, and the current efforts to generate side-effect free benzodiazepine alternatives, there is an urgent need for systematic, mechanistic research that provides a better understanding of the brain mechanisms of benzodiazepine misuse and abuse, including the involvement of specific GABAA receptor subtypes in these processes, to establish an informed foundation for preclinical and clinical efforts.
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Affiliation(s)
- Elif Engin
- Stress Neurobiology Laboratory, Division of Basic Neuroscience, McLean Hospital, Belmont, MA, United States.,Department of Psychiatry, Harvard Medical School, Boston, MA, United States
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Abstract
Addictive drugs are habit-forming. Addiction is a learned behavior; repeated exposure to addictive drugs can stamp in learning. Dopamine-depleted or dopamine-deleted animals have only unlearned reflexes; they lack learned seeking and learned avoidance. Burst-firing of dopamine neurons enables learning-long-term potentiation (LTP)-of search and avoidance responses. It sets the stage for learning that occurs between glutamatergic sensory inputs and GABAergic motor-related outputs of the striatum; this learning establishes the ability to search and avoid. Independent of burst-firing, the rate of single-spiking-or "pacemaker firing"-of dopaminergic neurons mediates motivational arousal. Motivational arousal increases during need states and its level determines the responsiveness of the animal to established predictive stimuli. Addictive drugs, while usually not serving as an external stimulus, have varying abilities to activate the dopamine system; the comparative abilities of different addictive drugs to facilitate LTP is something that might be studied in the future.
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Affiliation(s)
- Roy A Wise
- Intramural Research Program, National Institute on Drug Abuse, 250 Mason Lord Drive, Baltimore, MD, USA.
- Behavior Genetics Laboratory, McLean Hospital, Harvard Medical School, 115 Mill Street, Belmont, MA, 02478, USA.
| | - Chloe J Jordan
- Division of Alcohol, Drugs and Addiction, Department of Psychiatry, Harvard Medical School, McLean Hospital, 115 Mill Street, Belmont, MA, 02478, USA
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Jara CP, de Andrade Berti B, Mendes NF, Engel DF, Zanesco AM, Pereira de Souza GF, de Medeiros Bezerra R, de Toledo Bagatin J, Maria-Engler SS, Morari J, Velander WH, Velloso LA, Araújo EP. Glutamic acid promotes hair growth in mice. Sci Rep 2021; 11:15453. [PMID: 34326383 PMCID: PMC8322389 DOI: 10.1038/s41598-021-94816-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Accepted: 07/14/2021] [Indexed: 02/07/2023] Open
Abstract
Glutamic acid is the main excitatory neurotransmitter acting both in the brain and in peripheral tissues. Abnormal distribution of glutamic acid receptors occurs in skin hyperproliferative conditions such as psoriasis and skin regeneration; however, the biological function of glutamic acid in the skin remains unclear. Using ex vivo, in vivo and in silico approaches, we showed that exogenous glutamic acid promotes hair growth and keratinocyte proliferation. Topical application of glutamic acid decreased the expression of genes related to apoptosis in the skin, whereas glutamic acid increased cell viability and proliferation in human keratinocyte cultures. In addition, we identified the keratinocyte glutamic acid excitotoxic concentration, providing evidence for the existence of a novel skin signalling pathway mediated by a neurotransmitter that controls keratinocyte and hair follicle proliferation. Thus, glutamic acid emerges as a component of the peripheral nervous system that acts to control cell growth in the skin. These results raise the perspective of the pharmacological and nutritional use of glutamic acid to treat skin diseases.
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Affiliation(s)
- Carlos Poblete Jara
- Faculty of Nursing, University of Campinas, UNICAMP, Tessalia Vieira de Camargo St., 126, Campinas, SP, 13083-887, Brazil.
- Laboratory of Cell Signalling, Obesity and Comorbidities Research Center, University of Campinas, UNICAMP, Campinas, Brazil.
- University of Campinas, Campinas, Brazil.
- Department of Chemical and Biomolecular Engineering, University of Nebraska, Lincoln, NE, USA.
| | - Beatriz de Andrade Berti
- Faculty of Nursing, University of Campinas, UNICAMP, Tessalia Vieira de Camargo St., 126, Campinas, SP, 13083-887, Brazil
- Laboratory of Cell Signalling, Obesity and Comorbidities Research Center, University of Campinas, UNICAMP, Campinas, Brazil
- University of Campinas, Campinas, Brazil
| | - Natália Ferreira Mendes
- Faculty of Nursing, University of Campinas, UNICAMP, Tessalia Vieira de Camargo St., 126, Campinas, SP, 13083-887, Brazil
- Laboratory of Cell Signalling, Obesity and Comorbidities Research Center, University of Campinas, UNICAMP, Campinas, Brazil
- University of Campinas, Campinas, Brazil
| | - Daiane Fátima Engel
- Faculty of Medical Sciences, University of Campinas, UNICAMP, Campinas, Brazil
- Laboratory of Cell Signalling, Obesity and Comorbidities Research Center, University of Campinas, UNICAMP, Campinas, Brazil
- University of Campinas, Campinas, Brazil
| | - Ariane Maria Zanesco
- Faculty of Medical Sciences, University of Campinas, UNICAMP, Campinas, Brazil
- Laboratory of Cell Signalling, Obesity and Comorbidities Research Center, University of Campinas, UNICAMP, Campinas, Brazil
- University of Campinas, Campinas, Brazil
| | - Gabriela Freitas Pereira de Souza
- Department of Organic Chemistry, Institute of Chemistry, University of Campinas, UNICAMP, Campinas, Brazil
- University of Campinas, Campinas, Brazil
| | - Renan de Medeiros Bezerra
- Faculty of Nursing, University of Campinas, UNICAMP, Tessalia Vieira de Camargo St., 126, Campinas, SP, 13083-887, Brazil
- Laboratory of Cell Signalling, Obesity and Comorbidities Research Center, University of Campinas, UNICAMP, Campinas, Brazil
- University of Campinas, Campinas, Brazil
| | - Julia de Toledo Bagatin
- School of Pharmaceutical Sciences, Clinical Chemistry and Toxicology Department, University of São Paulo, São Paulo, Brazil
| | - Silvya Stuchi Maria-Engler
- School of Pharmaceutical Sciences, Clinical Chemistry and Toxicology Department, University of São Paulo, São Paulo, Brazil
| | - Joseane Morari
- Faculty of Medical Sciences, University of Campinas, UNICAMP, Campinas, Brazil
- Laboratory of Cell Signalling, Obesity and Comorbidities Research Center, University of Campinas, UNICAMP, Campinas, Brazil
- University of Campinas, Campinas, Brazil
| | - William H Velander
- Department of Chemical and Biomolecular Engineering, University of Nebraska, Lincoln, NE, USA
| | - Lício A Velloso
- Faculty of Medical Sciences, University of Campinas, UNICAMP, Campinas, Brazil
- Laboratory of Cell Signalling, Obesity and Comorbidities Research Center, University of Campinas, UNICAMP, Campinas, Brazil
- University of Campinas, Campinas, Brazil
| | - Eliana Pereira Araújo
- Faculty of Nursing, University of Campinas, UNICAMP, Tessalia Vieira de Camargo St., 126, Campinas, SP, 13083-887, Brazil
- Laboratory of Cell Signalling, Obesity and Comorbidities Research Center, University of Campinas, UNICAMP, Campinas, Brazil
- University of Campinas, Campinas, Brazil
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10
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Chen APF, Chen L, Kim TA, Xiong Q. Integrating the Roles of Midbrain Dopamine Circuits in Behavior and Neuropsychiatric Disease. Biomedicines 2021; 9:biomedicines9060647. [PMID: 34200134 PMCID: PMC8228225 DOI: 10.3390/biomedicines9060647] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/01/2021] [Accepted: 06/03/2021] [Indexed: 01/11/2023] Open
Abstract
Dopamine (DA) is a behaviorally and clinically diverse neuromodulator that controls CNS function. DA plays major roles in many behaviors including locomotion, learning, habit formation, perception, and memory processing. Reflecting this, DA dysregulation produces a wide variety of cognitive symptoms seen in neuropsychiatric diseases such as Parkinson’s, Schizophrenia, addiction, and Alzheimer’s disease. Here, we review recent advances in the DA systems neuroscience field and explore the advancing hypothesis that DA’s behavioral function is linked to disease deficits in a neural circuit-dependent manner. We survey different brain areas including the basal ganglia’s dorsomedial/dorsolateral striatum, the ventral striatum, the auditory striatum, and the hippocampus in rodent models. Each of these regions have different reported functions and, correspondingly, DA’s reflecting role in each of these regions also has support for being different. We then focus on DA dysregulation states in Parkinson’s disease, addiction, and Alzheimer’s Disease, emphasizing how these afflictions are linked to different DA pathways. We draw upon ideas such as selective vulnerability and region-dependent physiology. These bodies of work suggest that different channels of DA may be dysregulated in different sets of disease. While these are great advances, the fine and definitive segregation of such pathways in behavior and disease remains to be seen. Future studies will be required to define DA’s necessity and contribution to the functional plasticity of different striatal regions.
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Affiliation(s)
- Allen PF Chen
- Department of Neurobiology and Behavior, Renaissance School of Medicine at Stony Brook University, Stony Brook, NY 11794, USA; (A.P.C.); (L.C.); (T.A.K.)
- Medical Scientist Training Program, Renaissance School of Medicine at Stony Brook University, Stony Brook, NY 11794, USA
| | - Lu Chen
- Department of Neurobiology and Behavior, Renaissance School of Medicine at Stony Brook University, Stony Brook, NY 11794, USA; (A.P.C.); (L.C.); (T.A.K.)
| | - Thomas A. Kim
- Department of Neurobiology and Behavior, Renaissance School of Medicine at Stony Brook University, Stony Brook, NY 11794, USA; (A.P.C.); (L.C.); (T.A.K.)
- Medical Scientist Training Program, Renaissance School of Medicine at Stony Brook University, Stony Brook, NY 11794, USA
| | - Qiaojie Xiong
- Department of Neurobiology and Behavior, Renaissance School of Medicine at Stony Brook University, Stony Brook, NY 11794, USA; (A.P.C.); (L.C.); (T.A.K.)
- Correspondence:
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11
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Drug-Evoked Synaptic Plasticity of Excitatory Transmission in the Ventral Tegmental Area. Cold Spring Harb Perspect Med 2021; 11:cshperspect.a039701. [PMID: 32341062 DOI: 10.1101/cshperspect.a039701] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cocaine leads to a strong euphoria, which is at the origin of its recreational use. Past the acute effects, the drug leaves traces in the brain that persist long after it has been cleared from the body. These traces eventually shape behavior such that drug use may become compulsive, and addiction develops. Here, we discuss cocaine-evoked synaptic plasticity of glutamatergic transmission onto dopamine (DA) neurons of the ventral tegmental area (VTA) as one of the earliest traces after a first injection of cocaine. We review the literature that has examined the induction requirements, as well as the expression mechanism of this form of plasticity, and ask the question about its functional significance.
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12
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Kramer PF, Twedell EL, Shin JH, Zhang R, Khaliq ZM. Axonal mechanisms mediating γ-aminobutyric acid receptor type A (GABA-A) inhibition of striatal dopamine release. eLife 2020; 9:e55729. [PMID: 32870779 PMCID: PMC7462615 DOI: 10.7554/elife.55729] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 08/15/2020] [Indexed: 01/03/2023] Open
Abstract
Axons of dopaminergic neurons innervate the striatum where they contribute to movement and reinforcement learning. Past work has shown that striatal GABA tonically inhibits dopamine release, but whether GABA-A receptors directly modulate transmission or act indirectly through circuit elements is unresolved. Here, we use whole-cell and perforated-patch recordings to test for GABA-A receptors on the main dopaminergic neuron axons and branching processes within the striatum of adult mice. Application of GABA depolarized axons, but also decreased the amplitude of axonal spikes, limited propagation and reduced striatal dopamine release. The mechanism of inhibition involved sodium channel inactivation and shunting. Lastly, we show the positive allosteric modulator diazepam enhanced GABA-A currents on dopaminergic axons and directly inhibited release, but also likely acts by reducing excitation from cholinergic interneurons. Thus, we reveal the mechanisms of GABA-A receptor modulation of dopamine release and provide new insights into the actions of benzodiazepines within the striatum.
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Affiliation(s)
- Paul F Kramer
- Cellular Neurophysiology Unit, National Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaUnited States
| | - Emily L Twedell
- Cellular Neurophysiology Unit, National Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaUnited States
| | - Jung Hoon Shin
- Laboratory on Neurobiology of Compulsive Behaviors, National Institute of Alcohol Abuse and Alcoholism, National Institutes of HealthBethesdaUnited States
| | - Renshu Zhang
- Cellular Neurophysiology Unit, National Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaUnited States
| | - Zayd M Khaliq
- Cellular Neurophysiology Unit, National Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaUnited States
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13
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Understanding the effects of chronic benzodiazepine use in depression: a focus on neuropharmacology. Int Clin Psychopharmacol 2020; 35:243-253. [PMID: 32459725 DOI: 10.1097/yic.0000000000000316] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Benzodiazepines are frequently prescribed on an ongoing basis to individuals with depression, mainly to alleviate anxiety or insomnia, despite current guideline recommendations that continuous use should not exceed 4 weeks. Currently, there are no efficacy trials published beyond 8 weeks. Several antidepressant trials demonstrate that the concomitant use of a benzodiazepine is associated with poorer depressive outcomes and functional status; however, it is unclear why this is the case. Patients with depression receiving a benzodiazepine may reflect a more ill or high anxiety group, although even within anxiety disorders, the use of a benzodiazepine is associated with poorer outcomes. The neuroadaptive consequences of long-term benzodiazepine use may be a factor underlying these findings. Chronic benzodiazepine use results in decreased gamma-aminobutyric acid and monoaminergic function, as well as interference with neurogenesis, which are all purported to play a role in antidepressant efficacy. This review will discuss the oppositional neuropharmacological interactions between chronic benzodiazepine use and antidepressant mechanism of action, which could result in reduced antidepressant efficacy and function in depression.
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14
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Nagaeva E, Zubarev I, Bengtsson Gonzales C, Forss M, Nikouei K, de Miguel E, Elsilä L, Linden AM, Hjerling-Leffler J, Augustine GJ, Korpi ER. Heterogeneous somatostatin-expressing neuron population in mouse ventral tegmental area. eLife 2020; 9:59328. [PMID: 32749220 PMCID: PMC7440918 DOI: 10.7554/elife.59328] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 08/01/2020] [Indexed: 12/17/2022] Open
Abstract
The cellular architecture of the ventral tegmental area (VTA), the main hub of the brain reward system, remains only partially characterized. To extend the characterization to inhibitory neurons, we have identified three distinct subtypes of somatostatin (Sst)-expressing neurons in the mouse VTA. These neurons differ in their electrophysiological and morphological properties, anatomical localization, as well as mRNA expression profiles. Importantly, similar to cortical Sst-containing interneurons, most VTA Sst neurons express GABAergic inhibitory markers, but some of them also express glutamatergic excitatory markers and a subpopulation even express dopaminergic markers. Furthermore, only some of the proposed marker genes for cortical Sst neurons were expressed in the VTA Sst neurons. Physiologically, one of the VTA Sst neuron subtypes locally inhibited neighboring dopamine neurons. Overall, our results demonstrate the remarkable complexity and heterogeneity of VTA Sst neurons and suggest that these cells are multifunctional players in the midbrain reward circuitry.
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Affiliation(s)
- Elina Nagaeva
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Ivan Zubarev
- Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland
| | | | - Mikko Forss
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Kasra Nikouei
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Elena de Miguel
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Lauri Elsilä
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Anni-Maija Linden
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Jens Hjerling-Leffler
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - George J Augustine
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Esa R Korpi
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
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15
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Nagaeva E, Zubarev I, Bengtsson Gonzales C, Forss M, Nikouei K, de Miguel E, Elsilä L, Linden AM, Hjerling-Leffler J, Augustine GJ, Korpi ER. Heterogeneous somatostatin-expressing neuron population in mouse ventral tegmental area. eLife 2020. [PMID: 32749220 DOI: 10.1038/gene] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The cellular architecture of the ventral tegmental area (VTA), the main hub of the brain reward system, remains only partially characterized. To extend the characterization to inhibitory neurons, we have identified three distinct subtypes of somatostatin (Sst)-expressing neurons in the mouse VTA. These neurons differ in their electrophysiological and morphological properties, anatomical localization, as well as mRNA expression profiles. Importantly, similar to cortical Sst-containing interneurons, most VTA Sst neurons express GABAergic inhibitory markers, but some of them also express glutamatergic excitatory markers and a subpopulation even express dopaminergic markers. Furthermore, only some of the proposed marker genes for cortical Sst neurons were expressed in the VTA Sst neurons. Physiologically, one of the VTA Sst neuron subtypes locally inhibited neighboring dopamine neurons. Overall, our results demonstrate the remarkable complexity and heterogeneity of VTA Sst neurons and suggest that these cells are multifunctional players in the midbrain reward circuitry.
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Affiliation(s)
- Elina Nagaeva
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Ivan Zubarev
- Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland
| | | | - Mikko Forss
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Kasra Nikouei
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Elena de Miguel
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Lauri Elsilä
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Anni-Maija Linden
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Jens Hjerling-Leffler
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - George J Augustine
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Esa R Korpi
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
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16
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Berro LF, Rowlett JK. GABA A Receptor Subtypes and the Reinforcing Effects of Benzodiazepines in Remifentanil-Experienced Rhesus Monkeys. Drug Alcohol Depend 2020; 213:108076. [PMID: 32474260 PMCID: PMC7371532 DOI: 10.1016/j.drugalcdep.2020.108076] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 05/12/2020] [Accepted: 05/13/2020] [Indexed: 12/20/2022]
Abstract
BACKGROUND Opioid-use disorder is associated with a high degree of co-abuse with benzodiazepines. While the mechanisms underlying the co-abuse of opioids and benzodiazepines remain unknown, α1 subunit-containing GABAA receptors may play a critical role in the reinforcing effects of benzodiazepine-type compounds, depending on whether the monkeys have a history of benzodiazepine or stimulant self-administration. The present study extended our prior research by comparing the reinforcing effects of a compound lacking activity at α1 subunit-containing GABAA receptors with the reinforcing effects of non-selective GABAA receptor positive allosteric modulators in monkeys with a history of opioid self-administration. METHODS The reinforcing effects of L-838,417 (partial intrinsic efficacy at α2, α3, and α5 subunit-containing GABAA receptors, but no efficacy at α1 subunit-containing GABAA receptors, i.e., "α1-sparing compound") were compared with those of the non-selective GABAA receptor partial modulator MRK-696, and non-selective GABAA receptor full modulators, triazolam and lorazepam, in rhesus monkeys (n = 3) experienced in remifentanil self-administration under a progressive-ratio schedule of intravenous drug injection. RESULTS Neither the partial modulator nor the α1-sparing compound were self-administered above vehicle levels. The full modulators triazolam and lorazepam were self-administered significantly above vehicle levels, albeit at lower levels than remifentanil. CONCLUSIONS Our findings suggest that relatively high efficacy at one or more GABAA receptor subtypes is required for a compound to have reinforcing effects in monkeys with a history of remifentanil self-administration, in contrast to monkeys with benzodiazepine or stimulant self-administration histories.
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Affiliation(s)
- Lais F Berro
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, 2500 N State St, Jackson, MS, 39216, USA.
| | - James K Rowlett
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, 2500 N State St, Jackson, MS, 39216, USA
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17
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Pantazis CB, Aston‐Jones G. Lateral septum inhibition reduces motivation for cocaine: Reversal by diazepam. Addict Biol 2020; 25:e12742. [PMID: 30896079 DOI: 10.1111/adb.12742] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 01/20/2019] [Accepted: 02/05/2019] [Indexed: 12/17/2022]
Abstract
The lateral septum (LS) is a brain region implicated in motivation, addiction, anxiety, and affect. We recently found that LS is necessary for cocaine-seeking behaviors including conditioned place preference and reinstatement of extinguished drug seeking, which involve LS input to limbic regions including ventral tegmental area (VTA) and orexin neurons in hypothalamus. Here, we microinjected baclofen-muscimol (B-M) in LS prior to testing in a behavioral economics (BE) paradigm. We found that intra-LS B-M decreased motivation (increased demand elasticity; α) for cocaine, but did not change consumption at low effort (Q0 ). We also compared the effects of LS inhibition with the effects of treatment with the benzodiazepine diazepam, which has been shown to facilitate reward pathways and disinhibit VTA dopamine neurons. Pretreatment with diazepam blocked the effects of LS inhibition and restored cocaine demand to that following vehicle treatment. These changes in cocaine demand after LS inhibition or diazepam were not due to effects on anxiety, as both manipulations produced similar effects on anxiety measures but opposing effects on drug taking. Collectively, these studies point to LS as a critical region driving motivation for cocaine, likely through its interactions with the mesolimbic dopamine system.
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Affiliation(s)
- Caroline B. Pantazis
- Brain Health InstituteRutgers University/Rutgers Biomedical and Health Sciences Piscataway NJ USA
| | - Gary Aston‐Jones
- Brain Health InstituteRutgers University/Rutgers Biomedical and Health Sciences Piscataway NJ USA
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18
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de Miguel E, Vekovischeva O, Elsilä LV, Panhelainen A, Kankuri E, Aitta-Aho T, Korpi ER. Conditioned Aversion and Neuroplasticity Induced by a Superagonist of Extrasynaptic GABA A Receptors: Correlation With Activation of the Oval BNST Neurons and CRF Mechanisms. Front Mol Neurosci 2019; 12:130. [PMID: 31178693 PMCID: PMC6543524 DOI: 10.3389/fnmol.2019.00130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 05/03/2019] [Indexed: 11/13/2022] Open
Abstract
THIP (gaboxadol), a superagonist of the δ subunit-containing extrasynaptic GABAA receptors, produces persistent neuroplasticity in dopamine (DA) neurons of the ventral tegmental area (VTA), similarly to rewarding drugs of abuse. However, unlike them THIP lacks abuse potential and induces conditioned place aversion in mice. The mechanism underlying the aversive effects of THIP remains elusive. Here, we show that mild aversive effects of THIP were detected 2 h after administration likely reflecting an anxiety-like state with increased corticosterone release and with central recruitment of corticotropin-releasing factor corticotropin-releasing factor receptor 1 (CRF1) receptors. A detailed immunohistochemical c-Fos expression mapping for THIP-activated brain areas revealed a correlation between the activation of CRF-expressing neurons in the oval nucleus of the bed nuclei of stria terminalis and THIP-induced aversive effects. In addition, the neuroplasticity of mesolimbic DA system (24 h after administration) and conditioned place aversion by THIP after four daily acute sessions were dependent on extrasynaptic GABAA receptors (abolished in δ-GABAA receptor knockout mice) and activation of the CRF1 receptors (abolished in wildtype mice by a CRF1 receptor antagonist). A selective THIP-induced activation of CRF-expressing neurons in the oval part of the bed nucleus of stria terminalis may constitute a novel mechanism for inducing plasticity in a population of VTA DA neurons and aversive behavioral states.
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Affiliation(s)
- Elena de Miguel
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Olga Vekovischeva
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Lauri V Elsilä
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Anne Panhelainen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Esko Kankuri
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Teemu Aitta-Aho
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Esa R Korpi
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
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19
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Ueno F, Suzuki T, Nakajima S, Matsushita S, Mimura M, Miyazaki T, Takahashi T, Uchida H. Alteration in AMPA receptor subunit expression and receptor binding among patients with addictive disorders: A systematic review of human postmortem studies. Neuropsychopharmacol Rep 2019; 39:148-155. [PMID: 31070872 PMCID: PMC7292281 DOI: 10.1002/npr2.12058] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 03/12/2019] [Accepted: 04/02/2019] [Indexed: 02/06/2023] Open
Abstract
Background and Objectives Altered trafficking of α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid (AMPA) receptors has been reported in postmortem studies and suggested the involvement of AMPA receptors in the pathophysiology underpinning addictive disorders. However, these findings seemed mixed. Methods A systematic literature search was conducted, using PubMed and Embase (last search, August 2018), to identify human postmortem studies that examined the expression of proteins and mRNA of AMPA receptor subunits in patients with addictive disorders in comparison with healthy controls. Results Twelve (18 studies) out of 954 articles were identified to be relevant. Eight studies included alcohol use disorders, and four studies included heroin/cocaine abusers. The most frequently investigated regions were the hippocampus (three studies), amygdala (three studies), and putamen (three studies). In summary, two out of the three studies showed an increase in the expression of AMPA receptors in the hippocampus, while the other study found no change. Two studies to examine the amygdala demonstrated either a decreased or no change in receptor expression or binding. Concerning putamen, two studies showed no significant change whereas an overexpression of receptors was observed in the other. Conclusions and Scientific Significance The hippocampus and amygdala may be pertinent to addictive disorders through their functions on learning and memory, whereas findings in other regions were inconsistent across the studies. Human postmortem studies are prone to degenerative changes after death. Moreover, only qualitative assessment was conducted because of the limited, heterogenous data. These limitations emphasize the need to investigate AMPA receptors in the living human brains. Postmortem studies on AMPA receptors in patients with addiction show that the hippocampus and amygdala may be pertinent to addictive disorders through their functions on learning and memory, whereas findings in other regions were inconsistent across the studies. Human postmortem studies are prone to degenerative changes after death, which emphasizes the need to investigate AMPA receptors in the living human brains.![]()
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Affiliation(s)
- Fumihiko Ueno
- National Hospital Organization Kurihama Medical and Addiction Center, Yokosuka, Japan.,Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - Takefumi Suzuki
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan.,Department of Neuropsychiatry and Clinical Ethics, University of Yamanashi, Kofu, Japan
| | - Shinichiro Nakajima
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - Sachio Matsushita
- National Hospital Organization Kurihama Medical and Addiction Center, Yokosuka, Japan
| | - Masaru Mimura
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - Tomoyuki Miyazaki
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Takuya Takahashi
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama, Japan.,Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, New York
| | - Hiroyuki Uchida
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan.,Geriatric Mental Health Program, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
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20
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Abstract
OBJECTIVES Anxiety and adjustment disorders are among the most prevalent mental health conditions. This review focuses on γ-aminobutyric acid receptor type A (GABAAR)-mediated anxiolysis, describing the action of both endogenous and exogenous modulators of GABAAR. Future directions and innovative strategies to alleviate anxiety symptoms are discussed, with a particular emphasis on etifoxine. METHODS We used available data from the recent literature to update the mode of action of anxiolytics. We focussed our search on anxiolytics acting at GABAARs, as well as on the pharmacological properties of formerly and currently prescribed anxiolytics. RESULTS Considering the adverse effects of current treatments aimed at increasing inhibitory controls, optimisation of existing pharmacotherapies is of crucial importance. Among the alternative compounds targeting the GABAergic system, translocator protein (TSPO) ligands, such as etifoxine (EFX), which promote endogenous neurosteroidogenesis, are emerging as promising candidates for anxiety relief. In several papers comparing the efficacy of benzodiazepines and EFX, EFX showed interesting properties with limited side effects. Indeed, neurosteroids are potent GABAAR modulators with highly underrated anxiolytic properties. CONCLUSIONS Novel therapeutic strategies have been emerging following the recognition of neurosteroids as potent anxiolytics. Featured at the top of the list for well-tolerated anxiety relief, TSPO ligands such as etifoxine appear promising.
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Affiliation(s)
- Pierrick Poisbeau
- a Centre National de la Recherche Scientifique and University of Strasbourg, Institute for Cellular and Integrative Neuroscience (INCI) , Strasbourg , France
| | - Geraldine Gazzo
- a Centre National de la Recherche Scientifique and University of Strasbourg, Institute for Cellular and Integrative Neuroscience (INCI) , Strasbourg , France
| | - Laurent Calvel
- a Centre National de la Recherche Scientifique and University of Strasbourg, Institute for Cellular and Integrative Neuroscience (INCI) , Strasbourg , France
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21
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Normal extinction and reinstatement of morphine-induced conditioned place preference in the GluA1-KO mouse line. Behav Pharmacol 2018; 30:405-411. [PMID: 30376459 DOI: 10.1097/fbp.0000000000000449] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Extinction and reinstatement of morphine-induced conditioned place preference were studied in glutamate α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-receptor GluA1 subunit-deficient mice (global GluA1-KO mice). In line with previous findings, both acquisition and expression of conditioned place preference to morphine (20 mg/kg, subcutaneously) were fully functional in GluA1 KO mice compared with wild-type littermate controls (GluA1-WT), thus enabling the study of extinction. With a 10-session extinction paradigm, the GluA1 KO mice showed complete extinction similar to that of the GluA1-WT mice. Morphine-induced reinstatement (10 mg/kg, subcutaneously) was detected in both mouse lines. GluA1 KO mice moved more during all the phases of the experiment, including the place conditioning trials, extinction sessions, and place preference tests. The results suggest that the GluA1 subunit may be dispensable or prone to compensation at the neural circuitries delineating extinction and reinstatement. The GluA1 KO mice show altered long-term between-session habituation, which extends longer than previously anticipated.
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22
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Role of glutamatergic system and mesocorticolimbic circuits in alcohol dependence. Prog Neurobiol 2018; 171:32-49. [PMID: 30316901 DOI: 10.1016/j.pneurobio.2018.10.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 09/08/2018] [Accepted: 10/08/2018] [Indexed: 02/06/2023]
Abstract
Emerging evidence demonstrates that alcohol dependence is associated with dysregulation of several neurotransmitters. Alterations in dopamine, glutamate and gamma-aminobutyric acid release are linked to chronic alcohol exposure. The effects of alcohol on the glutamatergic system in the mesocorticolimbic areas have been investigated extensively. Several studies have demonstrated dysregulation in the glutamatergic systems in animal models exposed to alcohol. Alcohol exposure can lead to an increase in extracellular glutamate concentrations in mesocorticolimbic brain regions. In addition, alcohol exposure affects the expression and functions of several glutamate receptors and glutamate transporters in these brain regions. In this review, we discussed the effects of alcohol exposure on glutamate receptors, glutamate transporters and glutamate homeostasis in each area of the mesocorticolimbic system. In addition, we discussed the genetic aspect of alcohol associated with glutamate and reward circuitry. We also discussed the potential therapeutic role of glutamate receptors and glutamate transporters in each brain region for the treatment of alcohol dependence. Finally, we provided some limitations on targeting the glutamatergic system for potential therapeutic options for the treatment alcohol use disorders.
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23
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Siivonen MS, de Miguel E, Aaltio J, Manner AK, Vahermo M, Yli-Kauhaluoma J, Linden AM, Aitta-Aho T, Korpi ER. Conditioned Reward of Opioids, but not Psychostimulants, is Impaired in GABA-A Receptor δ Subunit Knockout Mice. Basic Clin Pharmacol Toxicol 2018; 123:558-566. [PMID: 29781560 DOI: 10.1111/bcpt.13043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 05/07/2018] [Indexed: 12/17/2022]
Abstract
Extrasynaptic δ subunit-containing γ-aminobutyric acid type A receptors (δ-GABAA Rs) are emerging as targets for a number of neuropsychopharmacological drugs, including the direct GABA site agonist gaboxadol and neuroactive steroids. Among other regions, these δ-GABAA Rs are functionally expressed in the ventral tegmental area (VTA), the cell body region of mesocorticolimbic dopamine (DA) system important for motivated behaviours, and in the target region, the nucleus accumbens. Gaboxadol and neurosteroids induce VTA DA neuron plasticity ex vivo, by inhibiting the VTA GABA neurons, and aversive place conditioning, which are absent in the δ-GABAA R knockout mice (δ-KO). It is not known whether δ-GABAA Rs are important for the effects of other drugs, such as opioids (that also inhibit GABA neurons) and stimulants (that primarily elevate monoamine levels). Here, we used δ-KO mice and conditioned place preference (CPP) test to study the rewarding effects of morphine (20 mg/kg), methamphetamine (1 mg/kg) and mephedrone (5 mg/kg). Morphine-induced nociception was also assessed using tail-flick and hot-plate tests. We found that the δ-KO mice failed to express morphine-induced CPP, but that they were more sensitive to morphine-induced analgesia in the tail-flick test. In contrast, stimulant-induced CPP in the δ-KO mice was similar to that in the wild-type controls. Thus, the conditioned rewarding effect by opioids, but not that of stimulants, was impaired in the absence of δ-GABAA Rs. Further studies are warranted to assess the potential of δ-GABAA R antagonists as possible targets for reducing morphine reward and potentiating morphine analgesia.
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Affiliation(s)
- Milo S Siivonen
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Elena de Miguel
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Juho Aaltio
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Aino K Manner
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Mikko Vahermo
- Drug Discovery Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Jari Yli-Kauhaluoma
- Drug Discovery Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Anni-Maija Linden
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Teemu Aitta-Aho
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Esa R Korpi
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
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24
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Vashchinkina E, Piippo O, Vekovischeva O, Krupitsky E, Ilyuk R, Neznanov N, Kazankov K, Zaplatkin I, Korpi ER. Addiction-related interactions of pregabalin with morphine in mice and humans: reinforcing and inhibiting effects. Addict Biol 2018; 23:945-958. [PMID: 28741741 DOI: 10.1111/adb.12538] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 06/15/2017] [Accepted: 06/26/2017] [Indexed: 12/11/2022]
Abstract
The gabapentinoid pregabalin is a rapid-acting anxiolytic and analgesic, possibly suitable in supervised opioid detoxification. However, clinicians have been cautious in using it because of its unknown addictive risk and rising number of mortalities after pregabalin self-medication in opioid abusers. Here, we studied interactions of pregabalin and morphine on reward functions of the dopamine system in mice and the efficacy of pregabalin on withdrawal in opioid addicts. After the treatment of mice with pregabalin and morphine, we used electrophysiology to study neuroplasticity in midbrain slices, self-administration and conditioned place preference tests to investigate the rewarding potential of pregabalin and naloxone-precipitated morphine withdrawal to evaluate opioid withdrawal symptoms. Further, we ran a pilot single-blind, randomized, controlled trial (34 heroin addicts) to evaluate the efficacy and safety of pregabalin in the treatment of opioid withdrawal syndrome. Pregabalin alone did not induce glutamate receptor neuroplasticity of dopamine neurons in the ventral tegmental area, but pre-treatment with pregabalin suppressed morphine-induced neuroplasticity, hyperlocomotion and morphine self-administration. Pregabalin administration after chronic morphine exposure failed to induce any rewarding effects. Instead, pregabalin suppressed withdrawal symptoms in both morphine-treated mice and opioid addicts and was well tolerated. Intriguingly, pregabalin administration after a low dose of morphine strongly facilitated ventral tegmental area neuroplasticity and led to increased conditioned place preference. Pregabalin appears to have the efficacy to counteract both reinforcing and withdrawal effects of opioids, but it also has a potentiating effect when given to mice with existing opioid levels.
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Affiliation(s)
- Elena Vashchinkina
- Department of Pharmacology, Faculty of Medicine; University of Helsinki; Helsinki Finland
| | - Ossi Piippo
- Department of Pharmacology, Faculty of Medicine; University of Helsinki; Helsinki Finland
| | - Olga Vekovischeva
- Department of Pharmacology, Faculty of Medicine; University of Helsinki; Helsinki Finland
| | - Evgeny Krupitsky
- Department of Addictions; St. Petersburg Bekhterev Research Psychoneurological Institute; St. Petersburg Russia
| | - Ruslan Ilyuk
- Department of Addictions; St. Petersburg Bekhterev Research Psychoneurological Institute; St. Petersburg Russia
| | - Nikholay Neznanov
- Department of Addictions; St. Petersburg Bekhterev Research Psychoneurological Institute; St. Petersburg Russia
| | | | | | - Esa R. Korpi
- Department of Pharmacology, Faculty of Medicine; University of Helsinki; Helsinki Finland
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Cheng T, Wallace DM, Ponteri B, Tuli M. Valium without dependence? Individual GABA A receptor subtype contribution toward benzodiazepine addiction, tolerance, and therapeutic effects. Neuropsychiatr Dis Treat 2018; 14:1351-1361. [PMID: 29872302 PMCID: PMC5973310 DOI: 10.2147/ndt.s164307] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Benzodiazepines are one of the most prescribed medications as first-line treatment of anxiety, insomnia, and epilepsy around the world. Over the past two decades, advances in the neuropharmacological understanding of gamma aminobutyric acid (GABA)A receptors revealed distinct contributions from each subtype and produced effects. Recent findings have highlighted the importance of α1 containing GABAA receptors in the mechanisms of addiction and tolerance in benzodiazepine treatments. This has shown promise in the development of tranquilizers with minimal side effects such as cognitive impairment, dependence, and tolerance. A valium-like drug without its side effects, as repeatedly demonstrated in animals, is achievable.
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Affiliation(s)
| | | | | | - Mahir Tuli
- University of British Columbia, Vancouver, BC, Canada
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26
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Cocaine Selectively Reorganizes Excitatory Inputs to Substantia Nigra Pars Compacta Dopamine Neurons. J Neurosci 2017; 38:1151-1159. [PMID: 29263240 DOI: 10.1523/jneurosci.1975-17.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 11/28/2017] [Accepted: 12/09/2017] [Indexed: 01/05/2023] Open
Abstract
Substantia nigra pars compacta (SNc) dopamine neurons and their targets are involved in addiction and cue-induced relapse. However, afferents onto SNc dopamine neurons themselves appear insensitive to drugs of abuse, such as cocaine, when afferents are collectively stimulated electrically. This contrasts with ventral tegmental area (VTA) dopamine neurons, whose glutamate afferents react robustly to cocaine. We used an optogenetic strategy to isolate identified SNc inputs and determine whether cocaine sensitivity in the mouse SNc circuit is conferred at the level of three glutamate afferents: dorsal raphé nucleus (DR), pedunculopontine nucleus (PPN), and subthalamic nucleus (STN). We found that excitatory afferents to SNc dopamine neurons are sensitive to cocaine in an afferent-specific manner. A single exposure to cocaine in vivo led to PPN-innervated synapses reducing the AMPA-to-NMDA receptor-mediated current ratio. In contrast to work in the VTA, this was due to increased NMDA receptor function with no change in AMPA receptor function. STN synapses showed a decrease in calcium-permeable AMPA receptors after cocaine, but no change in the AMPA-to-NMDA ratio. Cocaine also increased the release probability at DR-innervated and STN-innervated synapses, quantified by decreases in paired-pulse ratios. However, release probability at PPN-innervated synapses remained unaffected. By examining identified inputs, our results demonstrate a functional distribution among excitatory SNc afferent nuclei in response to cocaine, and suggest a compelling architecture for differentiation and separate parsing of inputs within the nigrostriatal system.SIGNIFICANCE STATEMENT Prior studies have established that substantia nigra pars compacta (SNc) dopamine neurons are a key node in the circuitry that drives addiction and relapse, yet cocaine apparently has no effect on electrically stimulated excitatory inputs. Our study is the first to demonstrate the functional impact of a drug of abuse on synaptic mechanisms of identified afferents to the SNc. Optogenetic dissection of inputs originating from dorsal raphé, pedunculopontine, and subthalamic nuclei were tested for synaptic modifications following in vivo cocaine exposure. Our results demonstrate that cocaine differentially induces modifications to SNc synapses depending on input origin. This presents implications for understanding dopamine processing of motivated behavior; most critically, it indicates that dopamine neurons selectively modulate signal reception processed by afferent nuclei.
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27
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Ostroumov A, Dani JA. Convergent Neuronal Plasticity and Metaplasticity Mechanisms of Stress, Nicotine, and Alcohol. Annu Rev Pharmacol Toxicol 2017; 58:547-566. [PMID: 28977763 DOI: 10.1146/annurev-pharmtox-010617-052735] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Stress and tobacco smoking are risk factors for alcoholism, but the underlying neural mechanisms are not well understood. Although stress, nicotine, and alcohol have broad, individual effects in the brain, some of their actions converge onto the same mechanisms and circuits. Stress and nicotine augment alcohol-related behaviors, in part via modulation of alcohol-evoked neuronal plasticity and metaplasticity mechanisms. Stress modulates alcohol-evoked plasticity via the release of signaling molecules that influence synaptic transmission. Nicotine also activates some of the same signaling molecules, cells, and circuits, producing a convergence of both stress and nicotine onto common plasticity mechanisms that influence alcohol self-administration. We describe several forms of alcohol-induced plasticity, including classic Hebbian plasticity at glutamatergic synapses, and we highlight less appreciated forms, such as non-Hebbian and GABAergic synaptic plasticity. Risk factors such as stress and nicotine initiate lasting neural changes that modify subsequent alcohol-induced synaptic plasticity and increase the vulnerability to alcohol addiction.
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Affiliation(s)
- Alexey Ostroumov
- Department of Neuroscience, Mahoney Institute for Neurosciences, Perelman School for Medicine, Philadelphia, Pennsylvania 19104, USA; ,
| | - John A Dani
- Department of Neuroscience, Mahoney Institute for Neurosciences, Perelman School for Medicine, Philadelphia, Pennsylvania 19104, USA; ,
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28
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Baimel C, Borgland SL. Hypocretin/Orexin and Plastic Adaptations Associated with Drug Abuse. Curr Top Behav Neurosci 2017; 33:283-304. [PMID: 28303403 DOI: 10.1007/7854_2016_44] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Dopamine neurons in the ventral tegmental area (VTA) are a critical part of the neural circuits that underlie reward learning and motivation. Dopamine neurons send dense projections throughout the brain and recent observations suggest that both the intrinsic properties and the functional output of dopamine neurons are dependent on projection target and are subject to neuromodulatory influences. Lateral hypothalamic hypocretin (also termed orexin) neurons project to the VTA and contain both hypocretin and dynorphin peptides in the same dense core vesicles suggesting they may be co-released. Hypocretin peptides act at excitatory Gαq protein-coupled receptors and dynorphin acts at inhibitory Gαi/o protein-coupled receptors, which are both expressed on subpopulations of dopamine neurons. This review describes a role for neuromodulation of dopamine neurons and the influence on motivated behaviour in response to natural and drug rewards.
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Affiliation(s)
- Corey Baimel
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, 2176 Health Sciences Mall, Vancouver, BC, Canada, V6T 1Z3
- Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Dr. NW, Calgary, AB, Canada, T2N 4N1
| | - Stephanie L Borgland
- Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Dr. NW, Calgary, AB, Canada, T2N 4N1.
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Manchester KR, Lomas EC, Waters L, Dempsey FC, Maskell PD. The emergence of new psychoactive substance (NPS) benzodiazepines: A review. Drug Test Anal 2017; 10:37-53. [DOI: 10.1002/dta.2211] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 04/11/2017] [Accepted: 04/26/2017] [Indexed: 01/17/2023]
Affiliation(s)
- Kieran R. Manchester
- School of Applied Sciences, Queensgate Campus; University of Huddersfield; Huddersfield UK
| | - Emma C. Lomas
- School of Applied Sciences, Queensgate Campus; University of Huddersfield; Huddersfield UK
| | - Laura Waters
- School of Applied Sciences, Queensgate Campus; University of Huddersfield; Huddersfield UK
| | - Fiona C. Dempsey
- MedAnnex Ltd, 1 Summerhall Place; Techcube 3.5; Edinburgh EH9 1PL UK
| | - Peter D. Maskell
- School of Science, Engineering and Technology; Abertay University; Dundee UK
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30
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Kumar M, Kumar M, Freund JM, Dillon GH. A Single Amino Acid Residue at Transmembrane Domain 4 of the α Subunit Influences Carisoprodol Direct Gating Efficacy at GABA A Receptors. J Pharmacol Exp Ther 2017. [PMID: 28642232 DOI: 10.1124/jpet.117.242156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The muscle relaxant carisoprodol has recently been controlled at the federal level as a Schedule IV drug due to its high abuse potential and consequences of misuse, such as withdrawal syndrome, delusions, seizures, and even death. Recent work has shown that carisoprodol can directly gate and allosterically modulate the type A GABA (GABAA) receptor. These actions are subunit-dependent; compared with other GABAA receptors, carisoprodol has nominal direct gating effects in α3β2γ2 receptors. Here, using site-directed mutagenesis and whole-cell patch-clamp electrophysiology in transiently transfected human embryonic kidney 293 cells, we examined the role of GABAA receptor α subunit transmembrane domain 4 (TM4) amino acids in direct gating and allosteric modulatory actions of carisoprodol. Mutation of α3 valine at position 440 to leucine (present in the equivalent position in the α1 subunit) significantly increased the direct gating effects of carisoprodol without affecting its allosteric modulatory effects. The corresponding reverse mutation, α1(L415V), decreased carisoprodol direct gating potency and efficacy. Analysis of a series of amino acid mutations at the 415 position demonstrated that amino acid volume correlated positively with carisoprodol efficacy, whereas polarity inversely correlated with carisoprodol efficacy. We conclude that α1(415) of TM4 is involved in the direct gating, but not allosteric modulatory, actions of carisoprodol. In addition, the orientation of alkyl or hydroxyl groups at this position influences direct gating effects. These findings support the likelihood that the direct gating and allosteric modulatory effects of carisoprodol are mediated via distinct binding sites.
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Affiliation(s)
- Manoj Kumar
- Department of Physiology and Pharmacology, Center for Neuroscience, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia (Mo.K., Mi.K., J.M.F., G.H.D.); and Center for Neuroscience Discovery, Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, Texas (Mi.K., G.H.D.)
| | - Manish Kumar
- Department of Physiology and Pharmacology, Center for Neuroscience, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia (Mo.K., Mi.K., J.M.F., G.H.D.); and Center for Neuroscience Discovery, Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, Texas (Mi.K., G.H.D.)
| | - John M Freund
- Department of Physiology and Pharmacology, Center for Neuroscience, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia (Mo.K., Mi.K., J.M.F., G.H.D.); and Center for Neuroscience Discovery, Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, Texas (Mi.K., G.H.D.)
| | - Glenn H Dillon
- Department of Physiology and Pharmacology, Center for Neuroscience, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia (Mo.K., Mi.K., J.M.F., G.H.D.); and Center for Neuroscience Discovery, Institute for Healthy Aging, University of North Texas Health Science Center, Fort Worth, Texas (Mi.K., G.H.D.)
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31
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Differential depression of neuronal network activity by midazolam and its main metabolite 1-hydroxymidazolam in cultured neocortical slices. Sci Rep 2017; 7:3503. [PMID: 28615640 PMCID: PMC5471240 DOI: 10.1038/s41598-017-03154-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 04/25/2017] [Indexed: 11/12/2022] Open
Abstract
The benzodiazepine midazolam is widely used in critical care medicine. Midazolam has a clinically active metabolite, 1-hydroxymidazolam. The contribution of 1-hydroxymidazolam to the effects of midazolam is controversial. The aim of the current study was to compare the actions of midazolam and 1-hydroxymidazolam on network activity of cortical neurons. Midazolam depressed neuronal activity at a low concentration of 5 nM. When midazolam concentration was increased, it depressed neuronal discharge rates in a biphasic manner. In comparison, 1-hydroxymidazolam did not depress the cortical network activity at low nanomolar concentrations. Higher concentrations of 1-hydroxymidazolam consistently inhibited neuronal activity. Moreover, midazolam shortened cortical up states at low, but not at high concentrations, while the opposite effect was observed with 1-hydroxymidazolam. The network depressant action of midazolam at low concentrations was absent in slices from GABAA receptor α1(H101R)mutant mice. The α1(H101R)mutation renders α1-subunit containing GABAA receptors insensitive towards benzodiazepines. This GABAA receptor subtype is thought to mediate sedation. As midazolam is more potent than its metabolite 1-hydroxymidazolam, the major clinical effects are thus likely caused by midazolam itself. However, 1-hydroxymidazolam could add to the effects of midazolam, especially after the application of high doses of midazolam, and in case of impaired drug metabolism.
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32
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Mazzitelli JY, Bonnafe E, Klopp C, Escudier F, Geret F. De novo transcriptome sequencing and analysis of freshwater snail (Radix balthica) to discover genes and pathways affected by exposure to oxazepam. ECOTOXICOLOGY (LONDON, ENGLAND) 2017; 26:127-140. [PMID: 27981403 DOI: 10.1007/s10646-016-1748-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/16/2016] [Indexed: 06/06/2023]
Abstract
Pharmaceuticals are increasingly found in aquatic ecosystems due to the non-efficiency of waste water treatment plants. Therefore, aquatic organisms are frequently exposed to a broad diversity of pharmaceuticals. Freshwater snail Radix balthica has been chosen as model to study the effects of oxazepam (psychotropic drug) on developmental stages ranging from trochophore to hatching. In order to provide a global insight of these effects, a transcriptome deep sequencing has been performed on exposed embryos. Eighteen libraries were sequenced, six libraries for three conditions: control, exposed to the lowest oxazepam concentration with a phenotypic effect (delayed hatching) (TA) and exposed to oxazepam concentration found in freshwater (TB). A total of 39,759,772 filtered raw reads were assembled into 56,435 contigs having a mean length of 1579.68 bp and mean depth of 378.96 reads. 44.91% of the contigs have at least one annotation. The differential expression analysis between the control condition and the two exposure conditions revealed 146 contigs differentially expressed of which 144 for TA and two for TB. 34.0% were annotated with biological function. There were four mainly impacted processes: two cellular signalling systems (Notch and JNK) and two biosynthesis pathways (Polyamine and Catecholamine pathways). This work reports a large-scale analysis of differentially transcribed genes of R. balthica exposed to oxazepam during egg development until hatching. In addition, these results enriched the de novo database of potential ecotoxicological models.
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Affiliation(s)
- Jean-Yves Mazzitelli
- Biochimie et Toxicologie des Substances Bioactives (BTSB), EA7417, Université de Toulouse, INU Champollion, Albi, France.
| | - Elsa Bonnafe
- Biochimie et Toxicologie des Substances Bioactives (BTSB), EA7417, Université de Toulouse, INU Champollion, Albi, France
| | - Christophe Klopp
- Unité de Mathématique et Informatique Appliquées de Toulouse, UR0875, INRA Toulouse, Castanet-Tolosan, France
| | - Frédéric Escudier
- Unité de Mathématique et Informatique Appliquées de Toulouse, UR0875, INRA Toulouse, Castanet-Tolosan, France
| | - Florence Geret
- Biochimie et Toxicologie des Substances Bioactives (BTSB), EA7417, Université de Toulouse, INU Champollion, Albi, France
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33
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Chagraoui A, Skiba M, Thuillez C, Thibaut F. To what extent is it possible to dissociate the anxiolytic and sedative/hypnotic properties of GABAA receptors modulators? Prog Neuropsychopharmacol Biol Psychiatry 2016; 71:189-202. [PMID: 27495357 DOI: 10.1016/j.pnpbp.2016.08.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 07/21/2016] [Accepted: 08/01/2016] [Indexed: 01/16/2023]
Abstract
The relatively common view indicates a possible dissociation between the anxiolytic and sedative/hypnotic properties of benzodiazepines (BZs). Indeed, GABAA receptor (GABAAR) subtypes have specific cerebral distribution in distinct neural circuits. Thus, GABAAR subtype-selective drugs may be expected to perform distinct functions. However, standard behavioral test assays provide limited direction towards highlighting new action mechanisms of ligands targeting GABAARs. Automated behavioral tests, lack sensitivity as some behavioral characteristics or subtle behavioral changes of drug effects or that are not considered in the overall analysis (Ohl et al., 2001) and observation-based analyses are not always performed. In addition, despite the use of genetically engineered mice, any possible dissociation between the anxiolytic and sedative properties of BZs remains controversial. Moreover, the involvement the different subtypes of GABAAR subtypes in the anxious behavior and the mechanism of action of anxiolytic agents remains unclear since there has been little success in the pharmacological investigations so far. This raises the question of the involvement of the different subunits in anxiolytic-like and/or sedative effects; and the actual implication of these subunits, particularly, α-subunits in the modulation of sedation and/or anxiety-related disorders. This present review was prompted by several conflicting studies on the degree of involvement of these subunits in anxiolytic-like and/or sedative effects. To this end, we explored the GABAergic system, particularly, the role of different subunits containing synaptic GABAARs. We report herein the targeting gene encoding the different subunits and their contribution in anxiolytic-like and/or sedative actions, as well as, the mechanism underlying tolerance to BZs.
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Affiliation(s)
- A Chagraoui
- Inserm U982, Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Institute for Research and Innovation in Biomedecine, Normandy University, France; Department of Medical Biochemistry, Rouen University Hospital, Rouen, France.
| | - M Skiba
- Inserm U982, Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Institute for Research and Innovation in Biomedecine, Normandy University, France
| | - C Thuillez
- Department of Pharmacology, Rouen University Hospital, Rouen, and INSERM U1096, Laboratory of New Pharmacological Targets for Endothelial Protection and Heart Failure, Institute for Research and Innovation in Biomedicine, Normandy University, France
| | - F Thibaut
- Department of Psychiatry, University Hospital Cochin (site Tarnier), University of Paris-Descartes and INSERM U 894 Laboratory of Psychiatry and Neurosciences, Paris, France
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Abstract
Addiction is a disease of altered behavior. Addicts use drugs compulsively and will continue to do so despite negative consequences. Even after prolonged periods of abstinence, addicts are at risk of relapse, particularly when cues evoke memories that are associated with drug use. Rodent models mimic many of the core components of addiction, from the initial drug reinforcement to cue-associated relapse and continued drug intake despite negative consequences. Rodent models have also enabled unprecedented mechanistic insight into addiction, revealing plasticity of glutamatergic synaptic transmission evoked by the strong activation of mesolimbic dopamine-a defining feature of all addictive drugs-as a neural substrate for these drug-adaptive behaviors. Cell type-specific optogenetic manipulations have allowed both identification of the relevant circuits and design of protocols to reverse drug-evoked plasticity and to establish links of causality with drug-adaptive behaviors. The emergence of a circuit model for addiction will open the door for novel therapies, such as deep brain stimulation.
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Affiliation(s)
- Christian Lüscher
- Department of Basic Neurosciences, Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland; .,Clinic of Neurology, Department of Clinical Neurosciences, Geneva University Hospital, CH-1211 Geneva, Switzerland
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Koskela M, Bäck S, Võikar V, Richie CT, Domanskyi A, Harvey BK, Airavaara M. Update of neurotrophic factors in neurobiology of addiction and future directions. Neurobiol Dis 2016; 97:189-200. [PMID: 27189755 DOI: 10.1016/j.nbd.2016.05.010] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 05/09/2016] [Accepted: 05/13/2016] [Indexed: 02/07/2023] Open
Abstract
Drug addiction is a chronic brain disease and drugs of abuse cause long lasting neuroadaptations. Addiction is characterized by the loss of control over drug use despite harmful consequences, and high rates of relapse even after long periods of abstinence. Neurotrophic factors (NTFs) are well known for their actions on neuronal survival in the peripheral nervous system. Moreover, NTFs have been shown to be involved in synaptic plasticity in the brain. Brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) are two of the most studied NTFs and both of them have been reported to increase craving when administered into the mesocorticolimbic dopaminergic system after drug self-administration. Here we review recent data on BDNF and GDNF functions in addiction-related behavior and discuss them in relation to previous findings. Finally, we give an insight into how new technologies could aid in further elucidating the role of these factors in drug addiction.
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Affiliation(s)
- Maryna Koskela
- Institute of Biotechnology, P.O. Box 56, 00014, University of Helsinki, Finland
| | - Susanne Bäck
- Intramural Research Program, National Institute on Drug Abuse, NIH, Baltimore, MD, USA
| | - Vootele Võikar
- Neuroscience Center, P.O. Box 56, 00014, University of Helsinki, Helsinki, Finland
| | - Christopher T Richie
- Intramural Research Program, National Institute on Drug Abuse, NIH, Baltimore, MD, USA
| | - Andrii Domanskyi
- Institute of Biotechnology, P.O. Box 56, 00014, University of Helsinki, Finland
| | - Brandon K Harvey
- Intramural Research Program, National Institute on Drug Abuse, NIH, Baltimore, MD, USA
| | - Mikko Airavaara
- Institute of Biotechnology, P.O. Box 56, 00014, University of Helsinki, Finland.
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36
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Lüscher C, Pascoli V, Creed M. Optogenetic dissection of neural circuitry: from synaptic causalities to blue prints for novel treatments of behavioral diseases. Curr Opin Neurobiol 2015; 35:95-100. [DOI: 10.1016/j.conb.2015.07.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Accepted: 07/21/2015] [Indexed: 11/26/2022]
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37
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Korpi ER, den Hollander B, Farooq U, Vashchinkina E, Rajkumar R, Nutt DJ, Hyytiä P, Dawe GS. Mechanisms of Action and Persistent Neuroplasticity by Drugs of Abuse. Pharmacol Rev 2015; 67:872-1004. [DOI: 10.1124/pr.115.010967] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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38
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Vashchinkina E, Panhelainen A, Aitta-Aho T, Korpi ER. GABAA receptor drugs and neuronal plasticity in reward and aversion: focus on the ventral tegmental area. Front Pharmacol 2014; 5:256. [PMID: 25505414 PMCID: PMC4243505 DOI: 10.3389/fphar.2014.00256] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 11/03/2014] [Indexed: 12/13/2022] Open
Abstract
GABAA receptors are the main fast inhibitory neurotransmitter receptors in the mammalian brain, and targets for many clinically important drugs widely used in the treatment of anxiety disorders, insomnia and in anesthesia. Nonetheless, there are significant risks associated with the long-term use of these drugs particularly related to development of tolerance and addiction. Addictive mechanisms of GABAA receptor drugs are poorly known, but recent findings suggest that those drugs may induce aberrant neuroadaptations in the brain reward circuitry. Recently, benzodiazepines, acting on synaptic GABAA receptors, and modulators of extrasynaptic GABAA receptors (THIP and neurosteroids) have been found to induce plasticity in the ventral tegmental area (VTA) dopamine neurons and their main target projections. Furthermore, depending whether synaptic or extrasynaptic GABAA receptor populations are activated, the behavioral outcome of repeated administration seems to correlate with rewarding or aversive behavioral responses, respectively. The VTA dopamine neurons project to forebrain centers such as the nucleus accumbens and medial prefrontal cortex, and receive afferent projections from these brain regions and especially from the extended amygdala and lateral habenula, forming the major part of the reward and aversion circuitry. Both synaptic and extrasynaptic GABAA drugs inhibit the VTA GABAergic interneurons, thus activating the VTA DA neurons by disinhibition and this way inducing glutamatergic synaptic plasticity. However, the GABAA drugs failed to alter synaptic spine numbers as studied from Golgi-Cox-stained VTA dendrites. Since the GABAergic drugs are known to depress the brain metabolism and gene expression, their likely way of inducing neuroplasticity in mature neurons is by disinhibiting the principal neurons, which remains to be rigorously tested for a number of clinically important anxiolytics, sedatives and anesthetics in different parts of the circuitry.
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Affiliation(s)
- Elena Vashchinkina
- Department of Pharmacology, Institute of Biomedicine, University of Helsinki Helsinki, Finland
| | - Anne Panhelainen
- Institute of Biotechnology, University of Helsinki Helsinki, Finland
| | - Teemu Aitta-Aho
- Department of Pharmacology, Institute of Biomedicine, University of Helsinki Helsinki, Finland ; Department of Pharmacology, University of Cambridge Cambridge, UK
| | - Esa R Korpi
- Department of Pharmacology, Institute of Biomedicine, University of Helsinki Helsinki, Finland ; Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, Neurobiology and Ageing Programme, Life Sciences Institute, National University of Singapore, and SINAPSE, Singapore Institute for Neurotechnology Singapore, Singapore
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Pathological circuit function underlying addiction and anxiety disorders. Nat Neurosci 2014; 17:1635-43. [PMID: 25402855 DOI: 10.1038/nn.3849] [Citation(s) in RCA: 149] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 09/29/2014] [Indexed: 02/07/2023]
Abstract
Current models of addiction and anxiety stem from the idea that aberrant function and remodeling of neural circuits cause the pathological behaviors. According to this hypothesis, a disease-defining experience (for example, drug reward or stress) would trigger specific forms of synaptic plasticity, which in susceptible subjects would become persistent and lead to the disease. While the notion of synaptic diseases has received much attention, no candidate disorder has been sufficiently investigated to yield new, rational therapies that could be tested in the clinic. Here we review the arguments in favor of abnormal neuronal plasticity underlying addiction and anxiety disorders, with a focus on the functional diversity of neurons that make up the circuits involved. We argue that future research must strive to obtain a comprehensive description of the relevant functional anatomy. This will allow identification of molecular mechanisms that govern the induction and expression of disease-relevant plasticity in identified neurons. To establish causality, one will have to test whether normalization of function can reverse pathological behavior. With these elements in hand, it will be possible to propose blueprints for manipulations to be tested in translational studies. The challenge is daunting, but new techniques, above all optogenetics, may enable decisive advances.
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Implication of mGlu5 receptor in the enhancement of morphine-induced hyperlocomotion under chronic treatment with zolpidem. Eur J Pharmacol 2014; 738:360-7. [DOI: 10.1016/j.ejphar.2014.06.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 05/30/2014] [Accepted: 06/02/2014] [Indexed: 02/04/2023]
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Wright BT, Gluszek CF, Heldt SA. The effects of repeated zolpidem treatment on tolerance, withdrawal-like symptoms, and GABAA receptor mRNAs profile expression in mice: comparison with diazepam. Psychopharmacology (Berl) 2014; 231:2967-79. [PMID: 24531568 DOI: 10.1007/s00213-014-3473-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 01/26/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE Zolpidem is a short-acting, non-benzodiazepine hypnotic that acts as a full agonist at α1-containing GABAA receptors. Overall, zolpidem purportedly has fewer instances of abuse and dependence than traditionally used benzodiazepines. However, several studies have shown that zolpidem may be more similar to benzodiazepines in terms of behavioral tolerance and withdrawal symptoms. OBJECTIVES In the current study, we examined whether subchronic zolpidem or diazepam administration produced deficits in zolpidem's locomotor-impairing effects, anxiety-like behaviors, and changes in GABAAR subunit messenger RNA (mRNA). METHODS Mice were given subchronic injections of either zolpidem (10 mg/kg), diazepam (20 mg/kg), or vehicle twice daily for 7 days. On day 8, mice were given a challenge dose of zolpidem (2 mg/kg) or vehicle before open field testing. Another set of mice underwent the same injection regimen but were sacrificed on day 8 for qRT-PCR analysis. RESULTS We found that subchronic zolpidem and diazepam administration produced deficits in the acute locomotor-impairing effects of zolpidem and increased anxiety-like behaviors 1 day after drug termination. In addition, we found that subchronic treatment of zolpidem and diazepam induced distinct but overlapping GABAAR subunit mRNA changes in the cortex but few changes in the hippocampus, amygdala, or prefrontal cortex. Levels of mRNA measured in separate mice after a single injection of either zolpidem or diazepam revealed no mRNA changes. CONCLUSIONS In mice, subchronic treatment of zolpidem and diazepam can produce deficits in the locomotor-impairing effects of zolpidem, anxiety-like withdrawal symptoms, and subunit-specific mRNA changes.
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Affiliation(s)
- Brittany T Wright
- The Department of Anatomy and Neurobiology, Neuroscience Institute, University of Tennessee Health Science Center, 855 Monroe Ave, Memphis, TN, 38163, USA
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Neural basis of benzodiazepine reward: requirement for α2 containing GABAA receptors in the nucleus accumbens. Neuropsychopharmacology 2014; 39:1805-15. [PMID: 24553732 PMCID: PMC4059902 DOI: 10.1038/npp.2014.41] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 01/15/2014] [Accepted: 01/21/2014] [Indexed: 11/09/2022]
Abstract
Despite long-standing concerns regarding the abuse liability of benzodiazepines, the mechanisms underlying properties of benzodiazepines that may be relevant to abuse are still poorly understood. Earlier studies showed that compounds selective for α1-containing GABAA receptors (α1GABAARs) are abused by humans and self-administered by animals, and that these receptors may underlie a preference for benzodiazepines as well as neuroplastic changes observed in the ventral tegmental area following benzodiazepine administration. There is some evidence, however, that even L-838, 417, a compound with antagonistic properties at α1GABAARs and agonistic properties at the other three benzodiazepine-sensitive GABAA receptor subtypes, is self-administered, and that the α2GABAARs may have a role in benzodiazepine-induced reward enhancement. Using a two-bottle choice drinking paradigm to evaluate midazolam preference and an intracranial self-stimulation (ICSS) paradigm to evaluate the impact of midazolam on reward enhancement, we demonstrated that mice carrying a histidine-to-arginine point mutation in the α2 subunit which renders it insensitive to benzodiazepines (α2(H101R) mice) did not prefer midazolam and did not show midazolam-induced reward enhancement in ICSS, in contrast to wild-type controls, suggesting that α2GABAARs are necessary for the reward enhancing effects and preference for oral benzodiazepines. Through a viral-mediated knockdown of α2GABAARs in the nucleus accumbens (NAc), we demonstrated that α2 in the NAc is necessary for the preference for midazolam. Findings imply that α2GABAARs in the NAc are involved in at least some reward-related properties of benzodiazepines, which might partially underlie repeated drug-taking behavior.
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The behavioral pharmacology of zolpidem: evidence for the functional significance of α1-containing GABA(A) receptors. Psychopharmacology (Berl) 2014; 231:1865-96. [PMID: 24563183 DOI: 10.1007/s00213-014-3457-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 01/11/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE Zolpidem is a positive allosteric modulator of γ-aminobutyric acid (GABA) with preferential binding affinity and efficacy for α1-subunit containing GABA(A) receptors (α1-GABA(A)Rs). Over the last three decades, a variety of animal models and experimental procedures have been used in an attempt to relate the behavioral profile of zolpidem and classic benzodiazepines (BZs) to their interaction with α1-GABA(A)Rs. OBJECTIVES This paper reviews the results of rodent and non-human primate studies that have evaluated the effects of zolpidem on motor behaviors, anxiety, memory, food and fluid intake, and electroencephalogram (EEG) sleep patterns. Also included are studies that examined zolpidem's discriminative, reinforcing, and anticonvulsant effects as well as behavioral signs of tolerance and withdrawal. RESULTS The literature reviewed indicates that α1-GABA(A)Rs play a principle role in mediating the hypothermic, ataxic-like, locomotor- and memory-impairing effects of zolpidem and BZs. Evidence also suggests that α1-GABA(A)Rs play partial roles in the hypnotic, EEG sleep, anticonvulsant effects, and anxiolytic-like of zolpidem and diazepam. These studies also indicate that α1-GABA(A)Rs play a more prominent role in mediating the discriminative stimulus, reinforcing, hyperphagic, and withdrawal effects of zolpidem and BZs in primates than in rodents. CONCLUSIONS The psychopharmacological data from both rodents and non-human primates suggest that zolpidem has a unique pharmacological profile when compared with classic BZs. The literature reviewed here provides an important framework for studying the role of different GABA(A)R subtypes in the behavioral effects of BZ-type drugs and helps guide the development of new pharmaceutical agents for disorders currently treated with BZ-type drugs.
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Kovačević J, Timić T, Tiruveedhula VV, Batinić B, Namjoshi OA, Milić M, Joksimović S, Cook JM, Savić MM. Duration of treatment and activation of α1-containing GABAA receptors variably affect the level of anxiety and seizure susceptibility after diazepam withdrawal in rats. Brain Res Bull 2014; 104:1-6. [PMID: 24695241 DOI: 10.1016/j.brainresbull.2014.03.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 03/04/2014] [Accepted: 03/21/2014] [Indexed: 10/25/2022]
Abstract
Long-term use of benzodiazepine-type drugs may lead to physical dependence, manifested by withdrawal syndrome after abrupt cessation of treatment. The aim of the present study was to investigate the influence of duration of treatment, as well as the role of α1-containing GABAA receptors, in development of physical dependence to diazepam, assessed through the level of anxiety and susceptibility to pentylenetetrazole (PTZ)-induced seizures, 24h after withdrawal from protracted treatment in rats. Withdrawal of 2mg/kg diazepam after 28, but not after 14 or 21 days of administration led to an anxiety-like behavior in the elevated plus maze. Antagonism of the diazepam effects at α1-containing GABAA receptors, achieved by daily administration of the neutral modulator βCCt (5mg/kg), did not affect the anxiety level during withdrawal. An increased susceptibility to PTZ-induced seizures was observed during diazepam withdrawal after 21 and 28 days of treatment. Daily co-administration of βCCt further decreased the PTZ-seizure threshold after 21 days of treatment, whilst it prevented the diazepam withdrawal-elicited decrease of the PTZ threshold after 28 days of treatment. In conclusion, the current study suggests that the role of α1-containing GABAA receptors in mediating the development of physical dependence may vary based on the effect being studied and duration of protracted treatment. Moreover, the present data supports previous findings that the lack of activity at α1-containing GABAA receptors is not sufficient to eliminate physical dependence liability of ligands of the benzodiazepine type.
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Affiliation(s)
- Jovana Kovačević
- Department of Pharmacology, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221 Belgrade, Serbia
| | - Tamara Timić
- Department of Pharmacology, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221 Belgrade, Serbia
| | - Veera V Tiruveedhula
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, WI 53201, USA
| | - Bojan Batinić
- Department of Pharmacology, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221 Belgrade, Serbia
| | - Ojas A Namjoshi
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, WI 53201, USA
| | - Marija Milić
- Department of Pharmacology, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221 Belgrade, Serbia
| | - Srđan Joksimović
- Department of Pharmacology, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221 Belgrade, Serbia
| | - James M Cook
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, WI 53201, USA
| | - Miroslav M Savić
- Department of Pharmacology, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221 Belgrade, Serbia.
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Vashchinkina E, Manner AK, Vekovischeva O, Hollander BD, Uusi-Oukari M, Aitta-aho T, Korpi ER. Neurosteroid Agonist at GABAA receptor induces persistent neuroplasticity in VTA dopamine neurons. Neuropsychopharmacology 2014; 39:727-37. [PMID: 24077066 PMCID: PMC3895251 DOI: 10.1038/npp.2013.258] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 08/20/2013] [Accepted: 08/20/2013] [Indexed: 02/05/2023]
Abstract
The main fast-acting inhibitory receptors in the mammalian brain are γ-aminobutyric acid type-A (GABAA) receptors for which neurosteroids, a subclass of steroids synthesized de novo in the brain, constitute a group of endogenous ligands with the most potent positive modulatory actions known. Neurosteroids can act on all subtypes of GABAA receptors, with a preference for δ-subunit-containing receptors that mediate extrasynaptic tonic inhibition. Pathological conditions characterized by emotional and motivational disturbances are often associated with perturbation in the levels of endogenous neurosteroids. We studied the effects of ganaxolone (GAN)-a synthetic analog of endogenous allopregnanolone that lacks activity on nuclear steroid receptors-on the mesolimbic dopamine (DA) system involved in emotions and motivation. A single dose of GAN in young mice induced a dose-dependent, long-lasting neuroplasticity of glutamate synapses of DA neurons ex vivo in the ventral tegmental area (VTA). Increased α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)/N-methyl-D-aspartate ratio and rectification of AMPA receptor responses even at 6 days after GAN administration suggested persistent synaptic targeting of GluA2-lacking AMPA receptors. This glutamate neuroplasticity was not observed in GABAA receptor δ-subunit-knockout (δ-KO) mice. GAN (500 nM) applied locally to VTA selectively increased tonic inhibition of GABA interneurons and triggered potentiation of DA neurons within 4 h in vitro. Place-conditioning experiments in adult wild-type C57BL/6J and δ-KO mice revealed aversive properties of repeated GAN administration that were dependent on the δ-subunits. Prolonged neuroadaptation to neurosteroids in the VTA might contribute to both the physiology and pathophysiology underlying processes and changes in motivation, mood, cognition, and drug addiction.
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Affiliation(s)
- Elena Vashchinkina
- Institute of Biomedicine, Pharmacology, University of Helsinki, Helsinki, Finland
| | - Aino K Manner
- Institute of Biomedicine, Pharmacology, University of Helsinki, Helsinki, Finland
| | - Olga Vekovischeva
- Institute of Biomedicine, Pharmacology, University of Helsinki, Helsinki, Finland
| | | | - Mikko Uusi-Oukari
- Department of Pharmacology, Drug Development and Therapeutics, University of Turku, Turku, Finland
| | - Teemu Aitta-aho
- Institute of Biomedicine, Pharmacology, University of Helsinki, Helsinki, Finland
| | - Esa R Korpi
- Institute of Biomedicine, Pharmacology, University of Helsinki, Helsinki, Finland,Institute of Biomedicine, Pharmacology, University of Helsinki, POB 63 (Haartmaninkatu 8), Helsinki FI-00014, Finland. Tel: +358 9 191 25330; Fax: +358 9 191 25364; E-mail:
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Creed MC, Ntamati NR, Tan KR. VTA GABA neurons modulate specific learning behaviors through the control of dopamine and cholinergic systems. Front Behav Neurosci 2014; 8:8. [PMID: 24478655 PMCID: PMC3897868 DOI: 10.3389/fnbeh.2014.00008] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 01/06/2014] [Indexed: 11/13/2022] Open
Abstract
The mesolimbic reward system is primarily comprised of the ventral tegmental area (VTA) and the nucleus accumbens (NAc) as well as their afferent and efferent connections. This circuitry is essential for learning about stimuli associated with motivationally-relevant outcomes. Moreover, addictive drugs affect and remodel this system, which may underlie their addictive properties. In addition to dopamine (DA) neurons, the VTA also contains approximately 30% γ-aminobutyric acid (GABA) neurons. The task of signaling both rewarding and aversive events from the VTA to the NAc has mostly been ascribed to DA neurons and the role of GABA neurons has been largely neglected until recently. GABA neurons provide local inhibition of DA neurons and also long-range inhibition of projection regions, including the NAc. Here we review studies using a combination of in vivo and ex vivo electrophysiology, pharmacogenetic and optogenetic manipulations that have characterized the functional neuroanatomy of inhibitory circuits in the mesolimbic system, and describe how GABA neurons of the VTA regulate reward and aversion-related learning. We also discuss pharmacogenetic manipulation of this system with benzodiazepines (BDZs), a class of addictive drugs, which act directly on GABAA receptors located on GABA neurons of the VTA. The results gathered with each of these approaches suggest that VTA GABA neurons bi-directionally modulate activity of local DA neurons, underlying reward or aversion at the behavioral level. Conversely, long-range GABA projections from the VTA to the NAc selectively target cholinergic interneurons (CINs) to pause their firing and temporarily reduce cholinergic tone in the NAc, which modulates associative learning. Further characterization of inhibitory circuit function within and beyond the VTA is needed in order to fully understand the function of the mesolimbic system under normal and pathological conditions.
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Affiliation(s)
- Meaghan C Creed
- Department of Basic Neurosciences, Medical Faculty, University of Geneva Geneva, Switzerland
| | - Niels R Ntamati
- Department of Basic Neurosciences, Medical Faculty, University of Geneva Geneva, Switzerland
| | - Kelly R Tan
- Department of Basic Neurosciences, Medical Faculty, University of Geneva Geneva, Switzerland
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Beckley JT, Woodward JJ. Volatile solvents as drugs of abuse: focus on the cortico-mesolimbic circuitry. Neuropsychopharmacology 2013; 38:2555-67. [PMID: 23954847 PMCID: PMC3828545 DOI: 10.1038/npp.2013.206] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 08/12/2013] [Accepted: 08/13/2013] [Indexed: 12/15/2022]
Abstract
Volatile solvents such as those found in fuels, paints, and thinners are found throughout the world and are used in a variety of industrial applications. However, these compounds are also often intentionally inhaled at high concentrations to produce intoxication. While solvent use has been recognized as a potential drug problem for many years, research on the sites and mechanisms of action of these compounds lags behind that of other drugs of abuse. In this review, we first discuss the epidemiology of voluntary solvent use throughout the world and then consider what is known about their basic pharmacology and how this may explain their use as drugs of abuse. We next present data from preclinical and clinical studies indicating that these substances induce common addiction sequelae such as dependence, withdrawal, and cognitive impairments. We describe how toluene, the most commonly studied psychoactive volatile solvent, alters synaptic transmission in key brain circuits such as the mesolimbic dopamine system and medial prefrontal cortex (mPFC) that are thought to underlie addiction pathology. Finally, we make the case that activity in mPFC circuits is a critical regulator of the mesolimbic dopamine system's ability to respond to volatile solvents like toluene. Overall, this review provides evidence that volatile solvents have high abuse liability because of their selective effects on critical nodes of the addiction neurocircuitry, and underscores the need for more research into how these compounds induce adaptations in neural circuits that underlie addiction pathology.
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Affiliation(s)
- Jacob T Beckley
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC, USA,Center for Drug and Alcohol Programs, Department of Psychiatry/Neurosciences, Medical University of South Carolina, Charleston, SC, USA
| | - John J Woodward
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC, USA,Center for Drug and Alcohol Programs, Department of Psychiatry/Neurosciences, Medical University of South Carolina, Charleston, SC, USA,Department of Neurosciences, Medical University of South Carolina, IOP 4 North, 67 President Street, MSC 861, Charleston, SC 29425, USA, Tel: +(843) 792 5225, Fax: +(843) 792 7353, E-mail:
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Abstract
RATIONALE An increasingly compelling literature points to a major role for the glutamate system in mediating the effects of alcohol on behavior and the pathophysiology of alcoholism. Preclinical studies indicate that glutamate signaling mediates certain aspects of ethanol's intoxicating and rewarding effects, and undergoes adaptations following chronic alcohol exposure that may contribute to the withdrawal, craving and compulsive drug-seeking that drive alcohol abuse and alcoholism. OBJECTIVES We discuss the potential for targeting the glutamate system as a novel pharmacotherapeutic approach to treating alcohol use disorders, focusing on five major components of the glutamate system: the N-methyl-D-aspartate (NMDA) receptor and specific NMDA subunits, the glycineB site on the NMDA receptors (NMDAR), L-alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid ionotropic (AMPA) and kainate (KAR) receptors, metabotropic receptors (mGluR), and glutamate transporters. RESULTS Chronic alcohol abuse produces a hyperglutamatergic state, characterized by elevated extracellular glutamate and altered glutamate receptors and transporters. Pharmacologically manipulating glutamatergic neurotransmission alters alcohol-related behaviors including intoxication, withdrawal, and alcohol-seeking, in rodents and human subjects. Blocking NMDA and AMPA receptors reduces alcohol consumption in rodents, but side-effects may limit this as a therapeutic approach. Selectively targeting NMDA and AMPA receptor subunits (e.g., GluN2B, GluA3), or the NMDAR glycineB site offers an alternative approach. Blocking mGluR5 potently affects various alcohol-related behaviors in rodents, and mGluR2/3 agonism also suppresses alcohol consumption. Finally, glutamate transporter upregulation may mitigate behavioral and neurotoxic sequelae of excess glutamate caused by alcohol. CONCLUSIONS Despite the many challenges that remain, targeting the glutamate system offers genuine promise for developing new treatments for alcoholism.
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Gantz SC, Bunzow JR, Williams JT. Spontaneous inhibitory synaptic currents mediated by a G protein-coupled receptor. Neuron 2013; 78:807-12. [PMID: 23764286 DOI: 10.1016/j.neuron.2013.04.013] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/09/2013] [Indexed: 11/30/2022]
Abstract
G protein-coupled receptors (GPCRs) affect many physiological processes by modulating both intrinsic membrane conductances and synaptic transmission. This study describes spontaneous miniature inhibitory postsynaptic currents mediated by vesicular dopamine release acting locally on metabotropic D2 receptors leading to the activation of a G protein-coupled inwardly rectifying potassium conductance. Thus, individual exocytotic events result in spontaneous GPCR-mediated transmission, similar to synaptic activation of classical ligand-gated ion channels.
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Affiliation(s)
- Stephanie C Gantz
- Vollum Institute, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
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