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Issa NP, Nunn KC, Wu S, Haider HA, Tao JX. Putative roles for homeostatic plasticity in epileptogenesis. Epilepsia 2023; 64:539-552. [PMID: 36617338 PMCID: PMC10015501 DOI: 10.1111/epi.17500] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 01/04/2023] [Accepted: 01/05/2023] [Indexed: 01/09/2023]
Abstract
Homeostatic plasticity allows neural circuits to maintain an average activity level while preserving the ability to learn new associations and efficiently transmit information. This dynamic process usually protects the brain from excessive activity, like seizures. However, in certain contexts, homeostatic plasticity might produce seizures, either in response to an acute provocation or more chronically as a driver of epileptogenesis. Here, we review three seizure conditions in which homeostatic plasticity likely plays an important role: acute drug withdrawal seizures, posttraumatic or disconnection epilepsy, and cyclic seizures. Identifying the homeostatic mechanisms active at different stages of development and in different circuits could allow better targeting of therapies, including determining when neuromodulation might be most effective, proposing ways to prevent epileptogenesis, and determining how to disrupt the cycle of recurring seizure clusters.
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Affiliation(s)
- Naoum P. Issa
- Comprehensive Epilepsy Center, Department of Neurology, 5841 S. Maryland Ave., MC 2030, University of Chicago, Chicago, IL 60637
| | | | - Shasha Wu
- Comprehensive Epilepsy Center, Department of Neurology, 5841 S. Maryland Ave., MC 2030, University of Chicago, Chicago, IL 60637
| | - Hiba A. Haider
- Comprehensive Epilepsy Center, Department of Neurology, 5841 S. Maryland Ave., MC 2030, University of Chicago, Chicago, IL 60637
| | - James X. Tao
- Comprehensive Epilepsy Center, Department of Neurology, 5841 S. Maryland Ave., MC 2030, University of Chicago, Chicago, IL 60637
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2
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Alcohol. Alcohol 2021. [DOI: 10.1016/b978-0-12-816793-9.00001-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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3
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Abstract
Alcohol is one of the oldest pharmacological agents used for its sedative/hypnotic effects, and alcohol abuse and alcohol use disorder (AUD) continues to be major public health issue. AUD is strongly indicated to be a brain disorder, and the molecular and cellular mechanism/s by which alcohol produces its effects in the brain are only now beginning to be understood. In the brain, synaptic plasticity or strengthening or weakening of synapses, can be enhanced or reduced by a variety of stimulation paradigms. Synaptic plasticity is thought to be responsible for important processes involved in the cellular mechanisms of learning and memory. Long-term potentiation (LTP) is a form of synaptic plasticity, and occurs via N-methyl-D-aspartate type glutamate receptor (NMDAR or GluN) dependent and independent mechanisms. In particular, NMDARs are a major target of alcohol, and are implicated in different types of learning and memory. Therefore, understanding the effect of alcohol on synaptic plasticity and transmission mediated by glutamatergic signaling is becoming important, and this will help us understand the significant contribution of the glutamatergic system in AUD. In the first part of this review, we will briefly discuss the mechanisms underlying long term synaptic plasticity in the dorsal striatum, neocortex and the hippocampus. In the second part we will discuss how alcohol (ethanol, EtOH) can modulate long term synaptic plasticity in these three brain regions, mainly from neurophysiological and electrophysiological studies. Taken together, understanding the mechanism(s) underlying alcohol induced changes in brain function may lead to the development of more effective therapeutic agents to reduce AUDs.
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Affiliation(s)
| | - Chitra D Mandyam
- VA San Diego Healthcare System, San Diego, CA, USA.,Department of Anesthesiology, University of California San Diego, San Diego, CA, USA
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4
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Turco CV, Arsalan SO, Nelson AJ. The Influence of Recreational Substance Use in TMS Research. Brain Sci 2020; 10:E751. [PMID: 33080965 PMCID: PMC7603156 DOI: 10.3390/brainsci10100751] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 10/13/2020] [Accepted: 10/15/2020] [Indexed: 12/30/2022] Open
Abstract
(1) Background: Transcranial magnetic stimulation (TMS) approaches are widely used to study cortical and corticospinal function. However, responses to TMS are subject to significant intra-and inter-individual variability. Acute and chronic exposure to recreational substances alters the excitability of the sensorimotor system and may contribute to the variability in TMS outcome measures. The increasing prevalence of recreational substance use poses a significant challenge for executing TMS studies, but there is a lack of clarity regarding the influence of these substances on sensorimotor function. (2) Methods: The literature investigating the influence of alcohol, nicotine, caffeine and cannabis on TMS outcome measures of corticospinal, intracortical and interhemispheric excitability was reviewed. (3) Results: Both acute and chronic use of recreational substances modulates TMS measures of excitability. Despite the abundance of research in this field, we identify knowledge gaps that should be addressed in future studies to better understand the influence of these substances on TMS outcomes. (4) Conclusions: This review highlights the need for TMS studies to take into consideration the history of participant substance use and to control for acute substance use prior to testing.
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Affiliation(s)
| | | | - Aimee J. Nelson
- Department of Kinesiology, McMaster University, Hamilton, ON L8S 4L8, Canada; (C.V.T.); (S.O.A.)
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5
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Lander M, Bastiampillai T, Sareen J. Review of withdrawal catatonia: what does this reveal about clozapine? Transl Psychiatry 2018; 8:139. [PMID: 30065280 PMCID: PMC6068101 DOI: 10.1038/s41398-018-0192-9] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 03/05/2018] [Accepted: 05/11/2018] [Indexed: 12/23/2022] Open
Abstract
Withdrawal symptoms are common upon discontinuation of psychiatric medications. Catatonia, a neuropsychiatric condition proposed to be associated with gamma-aminobutyric acid (GABA) hypoactivity due to its robust response to benzodiazepines, has been described as a withdrawal syndrome in case reports but is not a well-recognized phenomenon. The authors undertook a review of withdrawal catatonia with an aim to understand its presentation as well as the medications and psychoactive substances it is associated with. The review identified 55 cases of withdrawal catatonia, the majority of which occurred upon discontinuation of benzodiazepines (24 cases) and discontinuation of clozapine (20 cases). No other antipsychotic medications were identified as having been associated with the onset of a catatonic episode within 2 weeks following their discontinuation. Increasing GABA activity and resultant GABA receptor adaptations with prolonged use is postulated as a shared pharmacological mechanism between clozapine and benzodiazepines that underlie their association with withdrawal catatonia. The existing evidence for clozapine's activity on the GABA system is reviewed. The clinical presentations of benzodiazepine withdrawal catatonia and clozapine withdrawal catatonia appear to differ and reasons for this are explored. One reason is that benzodiazepines act directly on GABAA receptors as allosteric agonists, while clozapine has more complex and indirect interactions, primarily through effects on receptors located on GABA interneurons. Another possible reason for the difference in clinical presentation is that clozapine withdrawal catatonia may also involve receptor adaptations in non-GABA receptors such as dopamine and acetylcholine. The findings from our review have implications for the treatment of withdrawal catatonia, and treatment recommendations are provided. Further research understanding the uniqueness of clozapine withdrawal catatonia among antipsychotic medication may give some insight as to clozapine's differential mechanism of action.
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Affiliation(s)
- Matthew Lander
- Department of Psychiatry, University of Manitoba, Winnipeg, Canada.
| | - Tarun Bastiampillai
- Discipline of Psychiatry, School of Medicine, Flinders University, Adelaide, Australia
- South Australian Health and Medical Research Institute, Adelaide, Australia
| | - Jitender Sareen
- Departments of Psychiatry, Psychology, and Community Health Sciences, University of Manitoba, Winnipeg, Canada
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Histone deacetylases mediate GABA A receptor expression, physiology, and behavioral maladaptations in rat models of alcohol dependence. Neuropsychopharmacology 2018; 43. [PMID: 29520058 PMCID: PMC5983537 DOI: 10.1038/s41386-018-0034-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Alcohol use disorders are chronic debilitating diseases characterized by severe withdrawal symptoms that contribute to morbidity and relapse. GABAA receptor (GABAAR) adaptations have long been implicated in the chronic effects of alcohol and contribute to many withdrawal symptoms associated with alcohol dependence. In rodents, GABAAR hypofunction results from decreases in Gabra1 expression, although the underlying mechanism controlling Gabra1 expression after chronic ethanol exposure is still unknown. We found that chronic ethanol exposure using either ethanol gavage or two-bottle choice voluntary access paradigms decreased Gabra1 expression and increased Hdac2 and Hdac3 expression. Administration of the HDAC inhibitor trichostatin A (TSA) after chronic ethanol exposure prevents the decrease in Gabra1 expression and function as well as the increase in Hdac2 and Hdac3 expression in both the cortex and the medial prefrontal cortex (mPFC). Chronic ethanol exposure and withdrawal, but not acute ethanol exposure or acute withdrawal, cause a selective upregulation of HDAC2 and HDAC3 associated with the Gabra1 promoter that accompanies a decrease in H3 acetylation of the Gabra1 promoter and the reduction in GABAAR α1 subunit expression. TSA administration prevented each of these molecular events as well as behavioral manifestations of ethanol dependence, including tolerance to zolpidem-induced loss of righting reflex, reduced open-arm time in the elevated plus maze, reduced center-time and locomotor activity in the open-field assay, and TSA reduced voluntary ethanol consumption. The results show how chronic ethanol exposure regulates the highly prominent GABAAR α1 subunit by an epigenetic mechanism that represents a potential treatment modality for alcohol dependence.
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Cuzon Carlson VC. GABA and Glutamate Synaptic Coadaptations to Chronic Ethanol in the Striatum. Handb Exp Pharmacol 2018; 248:79-112. [PMID: 29460153 DOI: 10.1007/164_2018_98] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Alcohol (ethanol) is a widely used and abused drug with approximately 90% of adults over the age of 18 consuming alcohol at some point in their lifetime. Alcohol exerts its actions through multiple neurotransmitter systems within the brain, most notably the GABAergic and glutamatergic systems. Alcohol's actions on GABAergic and glutamatergic neurotransmission have been suggested to underlie the acute behavioral effects of ethanol. The striatum is the primary input nucleus of the basal ganglia that plays a role in motor and reward systems. The effect of ethanol on GABAergic and glutamatergic neurotransmission within striatal circuitry has been thought to underlie ethanol taking, seeking, withdrawal and relapse. This chapter reviews the effects of ethanol on GABAergic and glutamatergic transmission, highlighting the dynamic changes in striatal circuitry from acute to chronic exposure and withdrawal.
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Marszalek-Grabska M, Gibula-Bruzda E, Bodzon-Kulakowska A, Suder P, Gawel K, Talarek S, Listos J, Kedzierska E, Danysz W, Kotlinska JH. ADX-47273, a mGlu5 receptor positive allosteric modulator, attenuates deficits in cognitive flexibility induced by withdrawal from 'binge-like' ethanol exposure in rats. Behav Brain Res 2017; 338:9-16. [PMID: 29030082 DOI: 10.1016/j.bbr.2017.10.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 10/01/2017] [Accepted: 10/09/2017] [Indexed: 11/15/2022]
Abstract
Repeated exposure to and withdrawal from ethanol induces deficits in spatial reversal learning. Data indicate that metabotropic glutamate 5 (mGlu5) receptors are implicated in synaptic plasticity and learning and memory. These receptors functionally interact with N-methyl-d-aspartate (NMDA) receptors, and activation of one type results in the activation of the other. We examined whether (S)-(4-fluorophenyl)(3-(3-(4-fluorophenyl)-1,2,4-oxadiazol-5-yl)-piperidin-1-yl (ADX-47273), a positive allosteric modulator (PAM) of mGlu5 receptor, attenuates deficits in reversal learning induced by withdrawal (11-13days) from 'binge-like' ethanol input (5.0g/kg, i.g. for 5days) in the Barnes maze (a spatial learning) task in rats. We additionally examined the effects of ADX-47273 on the expression of the NMDA receptors subunit, GluN2B, in the hippocampus and prefrontal cortex, on the 13th day of ethanol withdrawal. Herein, withdrawal from repeated ethanol administration impaired reversal learning, but not the probe trial. Moreover, ADX-47273 (30mg/kg, i.p.) given prior to the first reversal learning trial for 3days in the Barnes maze, significantly enhanced performance in the ethanol-treated group. The 13th day of ethanol abstinence decreased the expression of the GluN2B subunit in the selected brain regions, but ADX-47273 administration increased it. In conclusion, positive allosteric modulation of mGlu5 receptors recovered spatial reversal learning impairment induced by withdrawal from 'binge-like' ethanol exposure. Such effect seems to be correlated with the mGlu5 receptors mediated potentiation of GluN2B-NMDA receptor mediated responses in the hippocampus and prefrontal cortex. Thus, our results emphasize the role of mGlu5 receptor PAM in the adaptive learning impaired by ethanol exposure.
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Affiliation(s)
| | - Ewa Gibula-Bruzda
- Department of Pharmacology and Pharmacodynamics, Medical University, Lublin, Poland
| | - Anna Bodzon-Kulakowska
- Department of Biochemistry and Neurobiology, AGH University of Science and Technology, Krakow, Poland
| | - Piotr Suder
- Department of Biochemistry and Neurobiology, AGH University of Science and Technology, Krakow, Poland
| | - Kinga Gawel
- Department of Pharmacology and Pharmacodynamics, Medical University, Lublin, Poland; Department of Experimental and Clinical Pharmacology, Medical University, Lublin, Poland
| | - Sylwia Talarek
- Department of Pharmacology and Pharmacodynamics, Medical University, Lublin, Poland
| | - Joanna Listos
- Department of Pharmacology and Pharmacodynamics, Medical University, Lublin, Poland
| | - Ewa Kedzierska
- Department of Pharmacology and Pharmacodynamics, Medical University, Lublin, Poland
| | | | - Jolanta H Kotlinska
- Department of Pharmacology and Pharmacodynamics, Medical University, Lublin, Poland.
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9
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Sari Y, Toalston JE, Rao PSS, Bell RL. Effects of ceftriaxone on ethanol, nicotine or sucrose intake by alcohol-preferring (P) rats and its association with GLT-1 expression. Neuroscience 2016; 326:117-125. [PMID: 27060486 DOI: 10.1016/j.neuroscience.2016.04.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 03/30/2016] [Accepted: 04/01/2016] [Indexed: 11/17/2022]
Abstract
Increased glutamatergic neurotransmission appears to mediate the reinforcing properties of drugs of abuse, including ethanol (EtOH). We have shown that administration of ceftriaxone (CEF), a β-lactam antibiotic, reduced EtOH intake and increased glutamate transporter 1 (GLT-1) expression in mesocorticolimbic regions of male and female alcohol-preferring (P) rats. In the present study, we tested whether CEF administration would reduce nicotine (NIC) and/or EtOH intake by adult female P rats. P rats were randomly assigned to 4 groups: (a) 5% sucrose (SUC) or 10% SUC [SUC], (b) 5% SUC+0.07mg/ml NIC and 10% SUC+0.14mg/ml NIC [NIC-SUC], 15% EtOH and 30% EtOH [EtOH] and (d) 15% EtOH+0.07mg/ml NIC and 30% EtOH+0.14mg/ml NIC [NIC-EtOH]. After achieving stable intakes (4weeks), the rats were administered 7 consecutive, daily i.p. injections of either saline or 200mg/kg CEF. The effects of CEF on intake were significant but differed across the reinforcers; such that ml/kg/day SUC was reduced by ∼30%, mg/kg/day NIC was reduced by ∼70% in the NIC-SUC group and ∼40% in the EtOH-NIC group, whereas g/kg/day EtOH was reduced by ∼40% in both the EtOH and EtOH-NIC group. The effects of CEF on GLT-1 expression were also studied. We found that CEF significantly increased GLT-1 expression in the prefrontal cortex and the nucleus accumbens of the NIC and NIC-EtOH rats as compared to NIC and NIC-EtOH saline-treated rats. These findings provide further support for GLT-1-associated mechanisms in EtOH and/or NIC abuse. The present results along with previous reports of CEF's efficacy in reducing cocaine self-administration in rats suggest that modulation of GLT-1 expression and/or activity is an important pharmacological target for treating polysubstance abuse and dependence.
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Affiliation(s)
- Youssef Sari
- University of Toledo, College of Pharmacy and Pharmaceutical Sciences, Department of Pharmacology, Toledo, OH 43614, USA.
| | - Jamie E Toalston
- Department of Psychiatry and Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - P S S Rao
- University of Toledo, College of Pharmacy and Pharmaceutical Sciences, Department of Pharmacology, Toledo, OH 43614, USA
| | - Richard L Bell
- Department of Psychiatry and Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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10
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Abstract
Cerebellar disorders trigger the symptoms of movement problems, imbalance, incoordination, and frequent fall. Cerebellar disorders are shown in various CNS illnesses including a drinking disorder called alcoholism. Alcoholism is manifested as an inability to control drinking in spite of adverse consequences. Human and animal studies have shown that cerebellar symptoms persist even after complete abstinence from drinking. In particular, the abrupt termination (ethanol withdrawal) of long-term excessive ethanol consumption has shown to provoke a variety of neuronal and mitochondrial damage to the cerebellum. Upon ethanol withdrawal, excitatory neurotransmitter molecules such as glutamate are overly released in brain areas including cerebellum. This is particularly relevant to the cerebellar neuronal network as glutamate signals are projected to Purkinje neurons through granular cells that are the most populated neuronal type in CNS. This excitatory neuronal signal may be elevated by ethanol withdrawal stress, which promotes an increase in intracellular Ca(2+) level and a decrease in a Ca(2+)-binding protein, both of which result in the excessive entry of Ca(2+) to the mitochondria. Subsequently, mitochondria undergo a prolonged opening of mitochondrial permeability transition pore and the overproduction of harmful free radicals, impeding adenosine triphosphate (ATP)-generating function. This in turn provokes the leakage of mitochondrial molecule cytochrome c to the cytosol, which triggers a cascade of adverse cytosol reactions. Upstream to this pathway, cerebellum under the condition of ethanol withdrawal has shown aberrant gene modifications through altered DNA methylation, histone acetylation, or microRNA expression. Interplay between these events and molecules may result in functional damage to cerebellar mitochondria and consequent neuronal degeneration, thereby contributing to motoric deficit. Mitochondria-targeting research may help develop a powerful new therapy to manage cerebellar disorders associated with hyperexcitatory CNS disorders like ethanol withdrawal.
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Affiliation(s)
- Marianna E Jung
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center at Fort Worth, 3500 Camp Bowie Blvd., Fort Worth, TX, 76107-2699, USA,
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Effects of pre-natal alcohol exposure on hippocampal synaptic plasticity: Sex, age and methodological considerations. Neurosci Biobehav Rev 2016; 64:12-34. [PMID: 26906760 DOI: 10.1016/j.neubiorev.2016.02.014] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 01/14/2016] [Accepted: 02/18/2016] [Indexed: 12/28/2022]
Abstract
The consumption of alcohol during gestation is detrimental to the developing central nervous system (CNS). The severity of structural and functional brain alterations associated with alcohol intake depends on many factors including the timing and duration of alcohol consumption. The hippocampal formation, a brain region implicated in learning and memory, is highly susceptible to the effects of developmental alcohol exposure. Some of the observed effects of alcohol on learning and memory may be due to changes at the synaptic level, as this teratogen has been repeatedly shown to interfere with hippocampal synaptic plasticity. At the molecular level alcohol interferes with receptor proteins and can disrupt hormones that are important for neuronal signaling and synaptic plasticity. In this review we examine the consequences of prenatal and early postnatal alcohol exposure on hippocampal synaptic plasticity and highlight the numerous factors that can modulate the effects of alcohol. We also discuss some potential mechanisms responsible for these changes as well as emerging therapeutic avenues that are beginning to be explored.
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12
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Anji A, Kumari M. Guardian of Genetic Messenger-RNA-Binding Proteins. Biomolecules 2016; 6:4. [PMID: 26751491 PMCID: PMC4808798 DOI: 10.3390/biom6010004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 12/02/2015] [Accepted: 12/04/2015] [Indexed: 12/18/2022] Open
Abstract
RNA in cells is always associated with RNA-binding proteins that regulate all aspects of RNA metabolism including RNA splicing, export from the nucleus, RNA localization, mRNA turn-over as well as translation. Given their diverse functions, cells express a variety of RNA-binding proteins, which play important roles in the pathologies of a number of diseases. In this review we focus on the effect of alcohol on different RNA-binding proteins and their possible contribution to alcohol-related disorders, and discuss the role of these proteins in the development of neurological diseases and cancer. We further discuss the conventional methods and newer techniques that are employed to identify RNA-binding proteins.
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Affiliation(s)
- Antje Anji
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA.
| | - Meena Kumari
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA.
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Van Skike CE, Diaz-Granados JL, Matthews DB. Chronic intermittent ethanol exposure produces persistent anxiety in adolescent and adult rats. Alcohol Clin Exp Res 2015; 39:262-71. [PMID: 25684048 DOI: 10.1111/acer.12617] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 10/28/2014] [Indexed: 11/27/2022]
Abstract
BACKGROUND Ethanol (EtOH) dependence and tolerance in the adult are marked by increased function of NMDA receptors and decreased function of GABAA receptors, which coincide with altered receptor subunit expression in specific brain regions. Adolescents often use EtOH at levels greater than adults, yet the receptor subunit expression profiles following chronic intermittent EtOH (CIE) exposure in adolescents are not known. Persistent age-dependent changes in receptor subunit alterations coupled with withdrawal-related anxiety may help explain the increase in alcohol abuse following adolescent experimentation with the drug. METHODS Adolescent and adult rats received 10 intraperitoneal administrations of 4.0 g/kg EtOH or saline every 48 hours. At either 24 hours or 12 days after the final exposure, anxiety-like behavior was assessed on the elevated plus maze and tissue was collected. Western blotting was used to assess changes in selected NMDA and GABAA receptor subunits in whole cortex and bilateral hippocampus. RESULTS CIE exposure yields a persistent increase in anxiety-like behavior in both age groups. However, selected NMDA and GABAA receptor subunits were not differentially altered by this CIE exposure paradigm in adolescents or adults. CONCLUSIONS CIE exposure produced persistent anxiety-like behavior, which has important implications for alcohol cessation. Given the reported behavioral and neuropeptide expression changes in response to this dose of EtOH, it is important for future work to consider the circumstances under which these measures are altered by EtOH exposure.
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Bekdash RA, Harrison NL. Downregulation of Gabra4 expression during alcohol withdrawal is mediated by specific microRNAs in cultured mouse cortical neurons. Brain Behav 2015; 5:e00355. [PMID: 26357588 PMCID: PMC4559018 DOI: 10.1002/brb3.355] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 03/27/2015] [Accepted: 04/25/2015] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Alcohol abuse and dependence are a serious public health problem. A large number of alcohol-regulated genes, (ARGs) are known to be influenced by alcohol use and withdrawal (AW), and recent evidence suggests that neuroadaptation to alcohol may be due in part to epigenetic changes in the expression of ARGs. Gabra4, which encodes the α4 subunit of GABAA receptors (GABAARs), is one of a number of ARGs that show remarkable plasticity in response to alcohol, being rapidly upregulated by acute alcohol exposure. This study addressed the effects of AW on changes in the expression of Gabra4 and related genes that encode other subunits of GABAARs, and the potential regulation of Gabra4 by microRNAs. METHODS We studied gene and microRNAs expression, using RT-PCR and microRNA microarray in cultured cortical neurons treated with alcohol, which was then removed in order to simulate AW in vitro. We also used microRNA mimics or inhibitors, and a promoter-reporter construct carrying the 3'UTR of Gabra4. RESULTS Eleven hours after removal of alcohol, Gabra4 was downregulated, with a modest increase in the expression of Gabrg2, but no change in the expression of Gabra1, Gabrd, or Gabrb2. microRNA profiling in neurons undergoing AW revealed upregulation in the expression of miR-155, miR-186, miR-24, and miR-375 after 8 h of AW. Transfection with molecular mimics of miR-186, miR-24, or miR-375 also downregulated Gabra4 expression, whereas transfection with the corresponding inhibitors of these microRNAs normalized Gabra4 expression in AW neurons to the level measured in control neurons. Promoter-reporter experiments supported the idea that miR-155, miR-186, miR-24, miR-27b, or miR-375 bind to the 3'UTR of Gabra4 and thereby inhibit protein production. CONCLUSIONS Our data suggest that AW decreases Gabra4 expression, and that this may be mediated in part by the induction of specific microRNAs in cortical neurons during AW.
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Affiliation(s)
- Rola A Bekdash
- Department of Anesthesiology, Columbia UniversityNew York, New York, 10032
| | - Neil L Harrison
- Department of Anesthesiology, Columbia UniversityNew York, New York, 10032
- Department of Pharmacology, Columbia UniversityNew York, New York, 10032
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15
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Chronic nicotine activates stress/reward-related brain regions and facilitates the transition to compulsive alcohol drinking. J Neurosci 2015; 35:6241-53. [PMID: 25878294 DOI: 10.1523/jneurosci.3302-14.2015] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Alcohol and nicotine are the two most co-abused drugs in the world. Previous studies have shown that nicotine can increase alcohol drinking in nondependent rats, yet it is unknown whether nicotine facilitates the transition to alcohol dependence. We tested the hypothesis that chronic nicotine will speed up the escalation of alcohol drinking in rats and that this effect will be accompanied by activation of sparsely distributed neurons (neuronal ensembles) throughout the brain that are specifically recruited by the combination of nicotine and alcohol. Rats were trained to respond for alcohol and made dependent using chronic, intermittent exposure to alcohol vapor, while receiving daily nicotine (0.8 mg/kg) injections. Identification of neuronal ensembles was performed after the last operant session, using immunohistochemistry. Nicotine produced an early escalation of alcohol drinking associated with compulsive alcohol drinking in dependent, but not in nondependent rats (air exposed), as measured by increased progressive-ratio responding and increased responding despite adverse consequences. The combination of nicotine and alcohol produced the recruitment of discrete and phenotype-specific neuronal ensembles (∼4-13% of total neuronal population) in the nucleus accumbens core, dorsomedial prefrontal cortex, central nucleus of the amygdala, bed nucleus of stria terminalis, and posterior ventral tegmental area. Blockade of nicotinic receptors using mecamylamine (1 mg/kg) prevented both the behavioral and neuronal effects of nicotine in dependent rats. These results demonstrate that nicotine and activation of nicotinic receptors are critical factors in the development of alcohol dependence through the dysregulation of a set of interconnected neuronal ensembles throughout the brain.
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Ramachandran B, Ahmed S, Zafar N, Dean C. Ethanol inhibits long-term potentiation in hippocampal CA1 neurons, irrespective of lamina and stimulus strength, through neurosteroidogenesis. Hippocampus 2014; 25:106-18. [PMID: 25155179 DOI: 10.1002/hipo.22356] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2014] [Indexed: 11/09/2022]
Abstract
Ethanol inhibits memory encoding and the induction of long-term potentiation (LTP) in CA1 neurons of the hippocampus. Hippocampal LTP at Schaffer collateral synapses onto CA1 pyramidal neurons has been widely studied as a cellular model of learning and memory, but there is striking heterogeneity in the underlying molecular mechanisms in distinct regions and in response to distinct stimuli. Basal and apical dendrites differ in terms of innervation, input specificity, and molecular mechanisms of LTP induction and maintenance, and different stimuli determine distinct molecular pathways of potentiation. However, lamina or stimulus-dependent effects of ethanol on LTP have not been investigated. Here, we tested the effect of acute application of 60 mM ethanol on LTP induction in distinct dendritic compartments (apical versus basal) of CA1 neurons, and in response to distinct stimulation paradigms (single versus repeated, spaced high frequency stimulation). We found that ethanol completely blocks LTP in apical dendrites, whereas it reduces the magnitude of LTP in basal dendrites. Acute ethanol treatment for just 15 min altered pre- and post-synaptic protein expression. Interestingly, ethanol increases the neurosteroid allopregnanolone, which causes ethanol-dependent inhibition of LTP, more prominently in apical dendrites, where ethanol has greater effects on LTP. This suggests that ethanol has general effects on fundamental properties of synaptic plasticity, but the magnitude of its effect on LTP differs depending on hippocampal sub-region and stimulus strength.
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Affiliation(s)
- Binu Ramachandran
- Trans-Synaptic Signaling Group, European Neuroscience Institute (ENI), Grisebachstrasse 5, 37077, Goettingen, Germany
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Sari Y. Role of glutamate transporter 1 in the attenuation of alcohol intake. Front Neurosci 2014; 8:200. [PMID: 25100932 PMCID: PMC4101336 DOI: 10.3389/fnins.2014.00200] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 06/26/2014] [Indexed: 01/07/2023] Open
Affiliation(s)
- Youssef Sari
- Department of Pharmacology, College of Pharmacy and Pharmaceutical Sciences, University of Toledo Toledo, OH, USA
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Abstract
Alcohol dependence is a complex disorder affecting all social and ethnic groups. Although the scientific understanding of the mechanism governing this multifactorial disease is still in its infancy, understanding its biological bases, including the potential contribution of genetic factors, is key to characterizing individual's risk and developing efficacious therapeutic target to combat the disease. This review provides an overview of different approaches that are being increasingly integrated to extend our knowledge of the genetic underpinnings of alcohol dependence.
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Affiliation(s)
- Awoyemi A Awofala
- a Department of Biological Sciences , Tai Solarin University of Education , Ijagun , Ogun State , Nigeria
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19
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Rao PSS, Sari Y. Glutamate transporter 1: target for the treatment of alcohol dependence. Curr Med Chem 2013; 19:5148-56. [PMID: 22680643 DOI: 10.2174/092986712803530511] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Revised: 05/04/2012] [Accepted: 05/07/2012] [Indexed: 12/19/2022]
Abstract
Emerging evidence indicates that many aspects of alcohol and drug dependence involve changes in glutamate transmission. A number of studies have reported that drugs of abuse, including alcohol and cocaine, alter glutamate transport. Extracellular glutamate is regulated by a number of glutamate transporters in various brain regions. Of these transporters, glutamate transporter (GLT1) is a key player in the removal of most of the extracellular glutamate. Similar to neurodegenerative disease models, in which there is dysfunction of the glutamatergic excitatory system, the role of GLT1 has been tested in drug dependence models that show dysfunction of glutamate transmission. We and others have recently found that ceftriaxone, an FDA-approved drug known to elevate GLT1 expression, attenuates cue-induced cocaine relapse. Moreover, we recently found that alcohol-preferring rats treated with ceftriaxone showed a significant dosedependent reduction in alcohol consumption. We also demonstrated that ceftriaxone-induced upregulation of GLT1 expression was associated with increases in glutamate uptake in Huntington's disease mouse model. Importantly, ceftriaxone is currently in clinical trials for the treatment of amyotrophic lateral sclerosis. This review provides information about the potential therapeutic role of GLT1 for the treatment of alcohol abuse and dependence.
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Affiliation(s)
- P S S Rao
- University of Toledo, College of Pharmacy and Pharmaceutical Sciences, Department of Pharmacology, Health Science Campus, 3000 Arlington Avenue, Toledo, OH 43614, USA
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20
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Sex differences in neuroadaptation to alcohol and withdrawal neurotoxicity. Pflugers Arch 2013; 465:643-54. [PMID: 23559099 DOI: 10.1007/s00424-013-1266-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 03/05/2013] [Accepted: 03/08/2013] [Indexed: 12/28/2022]
Abstract
Recent work suggests that sex differences exist with regard to both the nature of neuroadaptation to alcohol during the development of dependence, and possibly, the neurodegenerative consequences of alcohol dependence. Volumetric studies in human samples show that females may demonstrate increased volumetric brain loss with equal or lesser dependence histories than males. Furthermore, animal studies demonstrate sex differences in glutamatergic, GABAergic, and adenosinergic receptor signaling and endocrine responses following prolonged alcohol exposure. These differences may influence the development of dependence, neuronal function, and viability, particularly during alcohol withdrawal. The present review discusses the current state of knowledge in this regard. It is concluded that there exists a clear need for a more extensive examination of potential sex differences in neurodegenerative consequences of alcohol dependence in men and women, particularly with regard to the role that alterations in amino acid signaling and hypothalamic-pituitary-adrenal axis function may play. Furthermore, we note the need for expanded examination of the unique role that alcohol withdrawal-associated neuronal activity may have in the development of dependence-associated neurotoxicity.
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Sari Y, Franklin KM, Alazizi A, Rao PSS, Bell RL. Effects of ceftriaxone on the acquisition and maintenance of ethanol drinking in peri-adolescent and adult female alcohol-preferring (P) rats. Neuroscience 2013; 241:229-38. [PMID: 23537837 DOI: 10.1016/j.neuroscience.2013.03.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2012] [Revised: 02/15/2013] [Accepted: 03/07/2013] [Indexed: 10/27/2022]
Abstract
Increased glutamatergic neurotransmission appears to mediate the reinforcing properties of drugs of abuse, including ethanol (EtOH). We recently reported that the administration of ceftriaxone (CEF), a β-lactam antibiotic known to upregulate glutamate transporter 1 (GLT1) levels/activity, decreased the maintenance of EtOH intake in adult male alcohol-preferring (P) rats. In the present study, we tested whether CEF administration would reduce the acquisition and maintenance of EtOH drinking in adolescent and adult female P rats. The rats were treated with saline or 200mg/kg ceftriaxone for 7 days (starting at 35 or 75 days old, respectively) followed by the EtOH acquisition test. Five weeks later the effects of CEF were examined regarding the maintenance of EtOH intake. For the maintenance test, half of the animals that received CEF during acquisition received CEF for 7 days and the other half received saline for 7 days. Saline-treated acquisition animals were treated similarly. The results indicated that pretreatment with ceftriaxone reduced the maintenance of EtOH intake in both animals that started as adolescents and those that started as adults. However, the beneficial effect of CEF was more pronounced in rats pretreated with CEF as adults compared with rats pretreated as adolescents. Reductions in EtOH intake by ceftriaxone were paralleled by an upregulation of GLT1 protein levels in both the nucleus accumbens (∼25% in rats starting at both ages) and prefrontal cortex (∼50% in rats starting as peri-adolescents and ∼65% in those starting as adults). These findings provide further support for GLT1-associated mechanisms in high alcohol-consuming behavior, and hold promise for the development of effective treatments targeting alcohol abuse and dependence.
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Affiliation(s)
- Y Sari
- University of Toledo, College of Pharmacy and Pharmaceutical Sciences, Department of Pharmacology, Toledo, OH 43614, USA.
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22
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Abstract
Evidence indicates that the serotonergic system is important in mediating dependence on and craving for alcohol. Among serotonin receptors, 5-hydroxytryptamine 1B (5-HT1B) receptors have been associated with drug abuse including alcohol. In this review, the neurocircuitry involving 5-HT1B receptors in central reward brain regions related to alcohol intake are discussed in detail. Emphasis has been placed on the pharmacological manipulations of 5-HT1B receptor-mediated alcohol intake. Furthermore, 5-HT1B auto- and hetero-receptors regulate alcohol intake through the regulatory mechanism involving release of 5-HT, gamma-aminobutyric acid (GABA), dopamine, and glutamate is evaluated. Thus, interactions between 5-HT1B receptors and these neurotransmitter systems are suggested to modulate alcohol-drinking behavior. This review on the role of 5-HT1B receptors in neurotransmitter release and consequent alcohol intake provides important information about the potential therapeutic role of 5-HT1B receptors for the treatment of alcohol dependence.
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Affiliation(s)
- Youssef Sari
- University of Toledo, College of Pharmacy and Pharmaceutical Sciences, Department of Pharmacology, Toledo, OH 43614, USA.
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Mandyam CD. The Interplay between the Hippocampus and Amygdala in Regulating Aberrant Hippocampal Neurogenesis during Protracted Abstinence from Alcohol Dependence. Front Psychiatry 2013; 4:61. [PMID: 23818882 PMCID: PMC3694261 DOI: 10.3389/fpsyt.2013.00061] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 06/12/2013] [Indexed: 12/27/2022] Open
Abstract
The development of alcohol dependence involves elevated anxiety, low mood, and increased sensitivity to stress, collectively labeled negative affect. Particularly interesting is the recent accumulating evidence that sensitized extrahypothalamic stress systems [e.g., hyperglutamatergic activity, blunted hypothalamic-pituitary-adrenal (HPA) hormonal levels, altered corticotropin-releasing factor signaling, and altered glucocorticoid receptor signaling in the extended amygdala] are evident in withdrawn dependent rats, supporting the hypothesis that pathological neuroadaptations in the extended amygdala contribute to the negative affective state. Notably, hippocampal neurotoxicity observed as aberrant dentate gyrus (DG) neurogenesis (neurogenesis is a process where neural stem cells in the adult hippocampal subgranular zone generate DG granule cell neurons) and DG neurodegeneration are observed in withdrawn dependent rats. These correlations between withdrawal and aberrant neurogenesis in dependent rats suggest that alterations in the DG could be hypothesized to be due to compromised HPA axis activity and associated hyperglutamatergic activity originating from the basolateral amygdala in withdrawn dependent rats. This review discusses a possible link between the neuroadaptations in the extended amygdala stress systems and the resulting pathological plasticity that could facilitate recruitment of new emotional memory circuits in the hippocampus as a function of aberrant DG neurogenesis.
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Affiliation(s)
- Chitra D Mandyam
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute , La Jolla, CA , USA
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Early Postnatal Ethanol Exposure: Glutamatergic Excitotoxic Cell Death During Acute Withdrawal. NEUROPHYSIOLOGY+ 2012. [DOI: 10.1007/s11062-012-9308-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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25
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Griesmaier E, Keller M. Glutamate receptors — Prenatal insults, long-term consequences. Pharmacol Biochem Behav 2012; 100:835-40. [DOI: 10.1016/j.pbb.2011.04.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 03/23/2011] [Accepted: 04/15/2011] [Indexed: 10/18/2022]
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Broadwater M, Varlinskaya EI, Spear LP. Different chronic ethanol exposure regimens in adolescent and adult male rats: effects on tolerance to ethanol-induced motor impairment. Behav Brain Res 2011; 225:358-62. [PMID: 21782854 DOI: 10.1016/j.bbr.2011.07.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 06/24/2011] [Accepted: 07/06/2011] [Indexed: 10/18/2022]
Abstract
Findings are mixed regarding the expression of tolerance after repeated ethanol exposure, perhaps in part due to dose/frequency variations in exposure regimens. The present study compared age-related differences in tolerance development following 10 days of 1g/kg twice daily, 2g/kg once daily, or intermittent 4g/kg ethanol exposure regimens. To measure expression of chronic tolerance and acute tolerance, ethanol-induced motor impairment was assessed on day 12, with functionally equivalent ethanol doses administered across age (2g/kg - adolescents; 1.5g/kg - adults). Subsequent challenge doses resulted in lower brain ethanol concentrations in both age groups as a function of the chronic ethanol regimens. Expected age-related differences emerged in acute tolerance expression in non-manipulated animals, with adolescents, but not adults showing acute tolerance. Regimens sufficient to induce alterations in ethanol metabolism did not result in chronic functional tolerance at either age, although chronic injections were sufficient to induce acute tolerance in adults.
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Affiliation(s)
- Margaret Broadwater
- Center for Development and Behavioral Neuroscience, Department of Psychology, Binghamton University, Binghamton, NY 13902-6000, United States
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27
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Idrus NM, McGough NN, Spinetta MJ, Thomas JD, Riley EP. The effects of a single memantine treatment on behavioral alterations associated with binge alcohol exposure in neonatal rats. Neurotoxicol Teratol 2011; 33:444-50. [PMID: 21565269 PMCID: PMC3144286 DOI: 10.1016/j.ntt.2011.04.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Revised: 04/19/2011] [Accepted: 04/22/2011] [Indexed: 01/09/2023]
Abstract
BACKGROUND The third trimester in human fetal development represents a critical time of brain maturation referred to as the "brain growth spurt". This period occurs in rats postnatally, and exposure to ethanol during this time can increase the risk of impairments on a variety of cognitive and motor tasks. It has been proposed that one potential mechanism for the teratogenic effects of ethanol is NMDA receptor-mediated excitotoxicity during periods of ethanol withdrawal. In neonatal rats, antagonism of NMDA receptors during ethanol withdrawal, with drugs such as MK-801 and eliprodil, has been shown to mitigate some of the behavioral deficits induced by developmental ethanol exposure. The current study examined whether memantine, an NMDA receptor antagonist and a drug used clinically in Alzheimer's patients, would attenuate impairments associated with binge ethanol exposure in neonatal rats. METHODS On postnatal day 6, rats were exposed to 6 g/kg ethanol via intubation with controls receiving an isocaloric maltose dextrin solution. Twenty-one hours following the ethanol binge, rats received intraperitoneal injections of memantine at 0, 10, 15, or 20 mg/kg. Ethanol's teratogenic effects were assessed using multiple behavioral tasks: open field activity, parallel bars and spatial discrimination reversal learning. RESULTS Ethanol-treated rats were overactive in the open field and were impaired on both reversal learning and motor performance. Administration of 15 or 20 mg/kg memantine during withdrawal significantly attenuated ethanol's adverse effects on motor coordination, but did not significantly alter activity levels or improve the spatial learning deficits associated with neonatal alcohol exposure. CONCLUSION These results indicate that a single memantine administration during ethanol withdrawal can mitigate motor impairments but not spatial learning impairments or overactivity observed following a binge ethanol exposure during development in the rat.
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Affiliation(s)
- Nirelia M. Idrus
- Center for Behavioral Teratology, Department of Psychology, San Diego State University, 6330 Alvarado Ct., Ste 100, San Diego, CA 92120, USA
| | - Nancy N.H. McGough
- Center for Behavioral Teratology, Department of Psychology, San Diego State University, 6330 Alvarado Ct., Ste 100, San Diego, CA 92120, USA
| | - Michael J. Spinetta
- Center for Behavioral Teratology, Department of Psychology, San Diego State University, 6330 Alvarado Ct., Ste 100, San Diego, CA 92120, USA
| | - Jennifer D. Thomas
- Center for Behavioral Teratology, Department of Psychology, San Diego State University, 6330 Alvarado Ct., Ste 100, San Diego, CA 92120, USA
| | - Edward P. Riley
- Center for Behavioral Teratology, Department of Psychology, San Diego State University, 6330 Alvarado Ct., Ste 100, San Diego, CA 92120, USA
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28
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Idrus NM, McGough NNH, Riley EP, Thomas JD. Administration of memantine during ethanol withdrawal in neonatal rats: effects on long-term ethanol-induced motor incoordination and cerebellar Purkinje cell loss. Alcohol Clin Exp Res 2010; 35:355-64. [PMID: 21070252 DOI: 10.1111/j.1530-0277.2010.01351.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND Alcohol consumption during pregnancy can damage the developing fetus, illustrated by central nervous system dysfunction and deficits in motor and cognitive abilities. Binge drinking has been associated with an increased risk of fetal alcohol spectrum disorders, likely due to increased episodes of ethanol withdrawal. We hypothesized that overactivity of the N-methyl-D-aspartate (NMDA) receptor during ethanol withdrawal leads to excitotoxic cell death in the developing brain. Consistent with this, administration of NMDA receptor antagonists (e.g., MK-801) during withdrawal can attenuate ethanol's teratogenic effects. The aim of this study was to determine whether administration of memantine, an NMDA receptor antagonist, during ethanol withdrawal could effectively attenuate ethanol-related deficits, without the adverse side effects associated with other NMDA receptor antagonists. METHODS Sprague-Dawley pups were exposed to 6.0 g/kg ethanol or isocaloric maltose solution via intubation on postnatal day 6, a period of brain development equivalent to a portion of the 3rd trimester. Twenty-four and 36 hours after ethanol, subjects were injected with 0, 10, or 15 mg/kg memantine, totaling doses of 0, 20, or 30 mg/kg. Motor coordination was tested on a parallel bar task and the total number of cerebellar Purkinje cells was estimated using unbiased stereology. RESULTS Alcohol exposure induced significant parallel bar motor incoordination and reduced Purkinje cell number. Memantine administration significantly attenuated both ethanol-associated motor deficits and cerebellar cell loss in a dose-dependent manner. CONCLUSIONS Memantine was neuroprotective when administered during ethanol withdrawal. These data provide further support that ethanol withdrawal contributes to fetal alcohol spectrum disorders.
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Affiliation(s)
- Nirelia M Idrus
- Department of Psychology, Center for Behavioral Teratology, San Diego State University, California 92120, USA
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29
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Pian JP, Criado JR, Milner R, Ehlers CL. N-methyl-D-aspartate receptor subunit expression in adult and adolescent brain following chronic ethanol exposure. Neuroscience 2010; 170:645-54. [PMID: 20603193 DOI: 10.1016/j.neuroscience.2010.06.065] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Revised: 06/16/2010] [Accepted: 06/25/2010] [Indexed: 11/17/2022]
Abstract
Substantial evidence suggests that glutamatergic neurotransmission is a critical mediator of the experience-dependent synaptic plasticity that may underlie alcohol dependence. Substance abuse typically begins in adolescence; therefore, the impact of alcohol on glutamatergic systems during this critical time in brain development is of particular importance. The N-methyl-d-aspartate receptor (NMDAR) is involved in developmental mechanisms underlying neuronal differentiation and synaptogenesis and as such may be a target system for alcohol effects during adolescence. In the present study quantitative biochemical determinations were made of the relative abundance of different protein expressions of NMDAR subunits in adolescents and adults after 2 weeks of ethanol vapor exposure, and 24 h and 2 weeks following withdrawal. After 2 weeks of ethanol vapor exposure N-methyl-d-aspartate receptor NR1 subunit (NR1), N-methyl-d-aspartate receptor NR2A subunit (NR2A), and N-methyl-d-aspartate receptor NR2B subunit (NR2B) subunit expression was found to be increased in hippocampus of the adults. In contrast, 2 weeks of ethanol exposure resulted in no significant changes in NR1 and NR2B subunits and a reduction NR2A subunit expression in hippocampus in adolescents. Twenty-four h and 2 weeks following withdrawal from ethanol vapor NR1 and NR2A subunit expression in hippocampus was decreased in adolescents, whereas in adults it had returned to control levels. In frontal cortex, 2 weeks of chronic ethanol exposure produced decreases in NR1 subunit expression in both adults and adolescents but also produced decreases in NR2A and NR2B subunit expression in adults that returned or exceeded control levels by 2 weeks following withdrawal from ethanol vapor. These results demonstrate that NMDAR subunit composition can be modulated differentially between adolescents and adults by chronic ethanol exposure and withdrawal. These developmental differences in NMDAR subunits composition may also be associated with the enhanced vulnerability of the adolescent brain to ethanol dependence.
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Affiliation(s)
- J P Pian
- Department of Molecular and Integrative Neurosciences, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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Young BW, Sengelaub DR, Steinmetz JE. MK-801 administration during neonatal ethanol withdrawal attenuates interpositus cell loss and juvenile eyeblink conditioning deficits. Alcohol 2010; 44:359-69. [PMID: 20598489 DOI: 10.1016/j.alcohol.2009.12.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2009] [Revised: 12/17/2009] [Accepted: 12/30/2009] [Indexed: 02/06/2023]
Abstract
Binge-level doses of ethanol have been demonstrated to severely disrupt the cerebellum and cerebellum-dependent tasks when administered to rodent subjects during the early postnatal period. N-methyl-d-aspartic acid (NMDA) receptor-mediated excitotoxicity associated with ethanol withdrawal has been implicated as a significant component contributing to neurotoxic effects resulting from early ethanol exposure, and studies using MK-801 (dizocilpine) have reported protection from ethanol-induced damage. The present study examined whether the administration of MK-801 during ethanol withdrawal would ameliorate ethanol-associated cell death in the interpositus nucleus of the cerebellum and behavioral deficits in a cerebellar dependent task. Long Evans rat pups were treated with ethanol (5.25 g/kg) in a binge-like manner on postnatal day 6 using intragastric intubation. Subjects then received an injection of MK-801 (0.5mg/kg) or vehicle during withdrawal, 30h after ethanol exposure. Rats were then trained on an eyeblink classical conditioning task as juveniles (40 days of age), and cerebellar interpositus nucleus numbers were assessed after conditioning. Ethanol-exposed subjects exhibited reductions in neuronal populations and behavioral deficits during eyeblink conditioning. However, MK-801 administration significantly attenuated observed deficiencies, suggesting a protective effect resulting from MK-801 treatment during ethanol withdrawal. These results support the role of NMDA receptor-mediated excitotoxicity as a component mechanism by which ethanol produces teratogenicity. Additionally, our findings support previous reports that have shown correlations between dependent measures of eyeblink classical-conditioning behavior and unbiased cell counts in the interpositus nucleus.
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Affiliation(s)
- Brandt W Young
- Department of Physiology, Northwestern University, Chicago, IL, USA.
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Ehlers CL, Criado JR. Adolescent ethanol exposure: does it produce long-lasting electrophysiological effects? Alcohol 2010; 44:27-37. [PMID: 20113872 DOI: 10.1016/j.alcohol.2009.09.033] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Revised: 09/03/2009] [Accepted: 09/11/2009] [Indexed: 01/17/2023]
Abstract
This review discusses evidence for long-lasting neurophysiological changes that may occur following exposure to ethanol during adolescent development in animal models. Adolescence is the time that most individuals first experience ethanol exposure, and binge drinking is not uncommon during adolescence. If alcohol exposure is neurotoxic to the developing brain during adolescence, not unlike it is during fetal development, then understanding how ethanol affects the developing adolescent brain becomes a major public health issue. Adolescence is a critical time period when cognitive, emotional, and social maturation occurs and it is likely that ethanol exposure may affect these complex processes. To study the effects of ethanol on adolescent brain, animal models where the dose and time of exposure can be carefully controlled that closely mimic the human condition are needed. The studies reviewed provide evidence that demonstrates that relatively brief exposure to high levels of ethanol, via ethanol vapors, during a period corresponding to parts of adolescence in the rat is sufficient to cause long-lasting changes in functional brain activity. Disturbances in waking electroencephalogram and a reduction in the P3 component of the event-related potential (ERP) have been demonstrated in adult rats that were exposed to ethanol vapor during adolescence. Adolescent ethanol exposure was also found to produce long-lasting reductions in the mean duration of slow-wave sleep (SWS) episodes and the total amount of time spent in SWS, a finding consistent with a premature aging of sleep. Further studies are necessary to confirm these findings, in a range of strains, and to link those findings to the neuroanatomical and neurochemical mechanisms potentially underlying the lasting effects of adolescent ethanol exposure.
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Kumar S, Porcu P, Werner DF, Matthews DB, Diaz-Granados JL, Helfand RS, Morrow AL. The role of GABA(A) receptors in the acute and chronic effects of ethanol: a decade of progress. Psychopharmacology (Berl) 2009; 205:529-64. [PMID: 19455309 PMCID: PMC2814770 DOI: 10.1007/s00213-009-1562-z] [Citation(s) in RCA: 342] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Accepted: 04/30/2009] [Indexed: 12/12/2022]
Abstract
The past decade has brought many advances in our understanding of GABA(A) receptor-mediated ethanol action in the central nervous system. We now know that specific GABA(A) receptor subtypes are sensitive to ethanol at doses attained during social drinking while other subtypes respond to ethanol at doses attained by severe intoxication. Furthermore, ethanol increases GABAergic neurotransmission through indirect effects, including the elevation of endogenous GABAergic neuroactive steroids, presynaptic release of GABA, and dephosphorylation of GABA(A) receptors promoting increases in GABA sensitivity. Ethanol's effects on intracellular signaling also influence GABAergic transmission in multiple ways that vary across brain regions and cell types. The effects of chronic ethanol administration are influenced by adaptations in GABA(A) receptor function, expression, trafficking, and subcellular localization that contribute to ethanol tolerance, dependence, and withdrawal hyperexcitability. Adolescents exhibit altered sensitivity to ethanol actions, the tendency for higher drinking and longer lasting GABAergic adaptations to chronic ethanol administration. The elucidation of the mechanisms that underlie adaptations to ethanol exposure are leading to a better understanding of the regulation of inhibitory transmission and new targets for therapies to support recovery from ethanol withdrawal and alcoholism.
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Affiliation(s)
- Sandeep Kumar
- Department of Psychiatry, Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, 3027 Thurston-Bowles Building, CB #7178, Chapel Hill, NC 27599-7178, USA
| | - Patrizia Porcu
- Department of Psychiatry, Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, 3027 Thurston-Bowles Building, CB #7178, Chapel Hill, NC 27599-7178, USA
| | - David F. Werner
- Department of Psychiatry, Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, 3027 Thurston-Bowles Building, CB #7178, Chapel Hill, NC 27599-7178, USA
| | | | | | - Rebecca S. Helfand
- Department of Psychology and Neuroscience, Baylor University, Waco, TX, USA
| | - A. Leslie Morrow
- Department of Psychiatry, Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, 3027 Thurston-Bowles Building, CB #7178, Chapel Hill, NC 27599-7178, USA, Department of Pharmacology, Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, 3027 Thurston-Bowles Building, CB #7178, Chapel Hill, NC 27599-7178, USA
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Gee P, Gilbert M, Richardson S, Moore G, Paterson S, Graham P. Toxicity from the recreational use of 1-benzylpiperazine. Clin Toxicol (Phila) 2008; 46:802-7. [PMID: 18821145 DOI: 10.1080/15563650802307602] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
AIM This study describes the demographics and symptoms of patients, who presented to the Emergency Department (ED) in Christchurch, New Zealand, with toxicity from 1-benzylpiperazine (BZP)-based "party pills." BZP use has become widespread among the 16- to 30-year age group in New Zealand. This study explores the relationship between plasma BZP level and adverse effects experienced by users. The influence of ethanol co-ingestion was also studied. METHODS From 1 April 2005 to 1 July 2007, all BZP-related presentations to the ED were captured on a prospective data sheet. Patients were recruited to obtain plasma BZP levels, and these were correlated with the incidence of seizures and other symptoms. Coexistent ethanol use was also correlated with the frequency of seizures and other common BZP-induced symptoms. RESULTS In total 178 presentations with BZP toxicity were recorded. BZP levels were measured in 96. Sixty-nine percent of patients co-ingested other substances, with the most common substance being ethanol. In patients who ingested BZP alone, increased plasma BZP levels were associated with increased seizure frequency. Ethanol co-ingestion reduced the incidence of seizures, but significantly increased the likelihood of confusion and agitation. CONCLUSIONS Adverse effects from BZP commonly include confusion, agitation, vomiting, anxiety, and palpitations. There is strong evidence that higher plasma levels of BZP are associated with an increased incidence of seizures. Co-ingestion of ethanol increases the likelihood of common and distressing BZP-induced symptoms but reduces the incidence of BZP seizures.
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Affiliation(s)
- Paul Gee
- Department of Emergency Medicine, Christchurch Hospital, Christchurch, New Zealand.
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Criado JR, Wills DN, Walker BM, Ehlers CL. Electrophysiological effects of dizocilpine (MK-801) in adult rats exposed to ethanol during adolescence. Alcohol Clin Exp Res 2008; 32:1752-62. [PMID: 18652596 DOI: 10.1111/j.1530-0277.2008.00760.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND Despite evidence showing persistent changes in N-methyl-D-aspartate (NMDA)-receptor function following ethanol (EtOH) exposure, the contribution of NMDA systems to the long-term neurophysiological consequences of adolescent EtOH exposure is unclear. The aims of this study were the following: (1) to determine whether adolescent EtOH exposure produces neurophysiological changes after a prolonged withdrawal period in adult rats and (2) to assess protracted alterations in neurophysiological responses to the NMDA antagonist MK-801 in adult rats exposed to EtOH during adolescence. METHODS Adolescent male Wistar rats were exposed to EtOH vapor for 12 h/d for 5 weeks. The effects of MK-801 (0.0 to 0.1 mg/kg, intraperitoneally) on the electroencephalogram (EEG) and auditory event-related potentials (ERPs) were assessed after 8 weeks of abstinence from EtOH. RESULTS Experiments in aim 1 revealed that adolescent EtOH exposure reduced EEG variability in the frontal cortex in the 4 to 6 Hz band but had no effect on cortical and hippocampal EEG power and ERPs. Experiments in aim 2 showed that MK-801 significantly reduced EEG power in the parietal cortex (4 to 6 Hz, 6 to 8 Hz, 8 to 16 Hz, 16 to 32 Hz) and hippocampus (16 to 32 Hz) and EEG variability in the parietal cortex (6 to 8 Hz, 16 to 32 Hz) following adolescent EtOH exposure. MK-801 produced a significant decrease in hippocampal EEG variability (4 to 6 Hz, 8 to 16 Hz, 16 to 32 Hz) in control, but not in EtOH-exposed rats. MK-801 reduced frontal P1 ERP amplitude and latency in response to the rare tone in EtOH-exposed rats compared to controls. In contrast, MK-801 significantly reduced P3 ERP amplitude and latency in control, but not in EtOH-exposed rats. CONCLUSIONS The effects of MK-801 on hippocampal EEG variability and P3 ERP amplitude and latency are significantly attenuated after a prolonged withdrawal period following adolescent EtOH exposure. However, the inhibitory effects of MK-801 on cortical and hippocampal EEG power were enhanced in rats exposed to EtOH during adolescence. Taken together, these data suggest protracted changes in NMDA systems following adolescent EtOH exposure.
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Affiliation(s)
- José R Criado
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA
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KUMARI MEENA, ANJI ANTJE. An Old Story with a New Twist: Do NMDAR1 mRNA Binding Proteins Regulate Expression of the NMDAR1 Receptor in the Presence of Alcohol? Ann N Y Acad Sci 2008. [DOI: 10.1111/j.1749-6632.2005.tb00039.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Fujii S, Yamazaki Y, Sugihara T, Wakabayashi I. Acute and chronic ethanol exposure differentially affect induction of hippocampal LTP. Brain Res 2008; 1211:13-21. [PMID: 18423576 DOI: 10.1016/j.brainres.2008.02.052] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2007] [Revised: 02/19/2008] [Accepted: 02/20/2008] [Indexed: 11/30/2022]
Abstract
Using hippocampal slices, we found that chronic ethanol consumption by rats induces tolerance to the impairing effects of acute ethanol treatment on induction of long-term potentiation (LTP) in CA1 neurons. In hippocampal slices from pair-fed control rats, stable LTP was induced by tetanic stimulation consisting of 25 or more pulses at 100 Hz, but not by tetanic stimulation of 15 pulses at 100 Hz, and LTP induction was blocked if the tetanus was delivered in the presence of 8.6 mM ethanol, 1 microM muscimol, a gamma-aminobutyric acid (GABA) A receptor agonist, or 2.5 microM dl-2-amino-5-phosphonovaleric acid (AP5), an N-methyl-d-aspartate (NMDA) receptor antagonist. In hippocampal slices from rats chronically fed a liquid diet containing ethanol, a tetanus consisting of 15 pulses at 100 Hz did induce stable LTP, indicating a decrease in the stimulation threshold for inducing LTP. Application of ethanol, muscimol, or AP5 did not affect LTP induction in these cells, suggesting that the effects of chronic ethanol exposure on LTP induction are mediated by a reduction in GABAergic inhibition or an increase in NMDA receptor activity in hippocampal CA1 neurons.
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Affiliation(s)
- Satoshi Fujii
- Department of Physiology, Yamagata University School of Medicine, Yamagata 990-9585, Japan.
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Gass JT, Olive MF. Glutamatergic substrates of drug addiction and alcoholism. Biochem Pharmacol 2008; 75:218-65. [PMID: 17706608 PMCID: PMC2239014 DOI: 10.1016/j.bcp.2007.06.039] [Citation(s) in RCA: 355] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2007] [Revised: 06/22/2007] [Accepted: 06/26/2007] [Indexed: 12/20/2022]
Abstract
The past two decades have witnessed a dramatic accumulation of evidence indicating that the excitatory amino acid glutamate plays an important role in drug addiction and alcoholism. The purpose of this review is to summarize findings on glutamatergic substrates of addiction, surveying data from both human and animal studies. The effects of various drugs of abuse on glutamatergic neurotransmission are discussed, as are the effects of pharmacological or genetic manipulation of various components of glutamate transmission on drug reinforcement, conditioned reward, extinction, and relapse-like behavior. In addition, glutamatergic agents that are currently in use or are undergoing testing in clinical trials for the treatment of addiction are discussed, including acamprosate, N-acetylcysteine, modafinil, topiramate, lamotrigine, gabapentin and memantine. All drugs of abuse appear to modulate glutamatergic transmission, albeit by different mechanisms, and this modulation of glutamate transmission is believed to result in long-lasting neuroplastic changes in the brain that may contribute to the perseveration of drug-seeking behavior and drug-associated memories. In general, attenuation of glutamatergic transmission reduces drug reward, reinforcement, and relapse-like behavior. On the other hand, potentiation of glutamatergic transmission appears to facilitate the extinction of drug-seeking behavior. However, attempts at identifying genetic polymorphisms in components of glutamate transmission in humans have yielded only a limited number of candidate genes that may serve as risk factors for the development of addiction. Nonetheless, manipulation of glutamatergic neurotransmission appears to be a promising avenue of research in developing improved therapeutic agents for the treatment of drug addiction and alcoholism.
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Affiliation(s)
- Justin T Gass
- Center for Drug and Alcohol Programs, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
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Biggio G, Concas A, Follesa P, Sanna E, Serra M. Stress, ethanol, and neuroactive steroids. Pharmacol Ther 2007; 116:140-71. [PMID: 17555824 PMCID: PMC3000046 DOI: 10.1016/j.pharmthera.2007.04.005] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2007] [Accepted: 04/06/2007] [Indexed: 12/27/2022]
Abstract
Neurosteroids play a crucial role in stress, alcohol dependence and withdrawal, and other physiological and pharmacological actions by potentiating or inhibiting neurotransmitter action. This review article focuses on data showing that the interaction among stress, ethanol, and neuroactive steroids may result in plastic molecular and functional changes of GABAergic inhibitory neurotransmission. The molecular mechanisms by which stress-ethanol-neuroactive steroids interactions can produce plastic changes in GABA(A) receptors have been studied using different experimental models in vivo and in vitro in order to provide useful evidence and new insights into the mechanisms through which acute and chronic ethanol and stress exposure modulate the activity of GABAergic synapses. We show detailed data on a) the effect of acute and chronic stress on peripheral and brain neurosteroid levels and GABA(A) receptor gene expression and function; b) ethanol-stimulated brain steroidogenesis; c) plasticity of GABA(A) receptor after acute and chronic ethanol exposure. The implications of these new mechanistic insights to our understanding of the effects of ethanol during stress are also discussed. The understanding of these neurochemical and molecular mechanisms may shed new light on the physiopathology of diseases, such as anxiety, in which GABAergic transmission plays a pivotal role. These data may also lead to the need for new anxiolytic, hypnotic and anticonvulsant selective drugs devoid of side effects.
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Affiliation(s)
- Giovanni Biggio
- Department of Experimental Biology, Center of Excellence for the Neurobiology of Dependence, University of Cagliari, Cagliari, Italy.
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Sharma AN, Chopde CT, Hirani K, Kokare DM, Ugale RR. Chronic progesterone treatment augments while dehydroepiandrosterone sulphate prevents tolerance to ethanol anxiolysis and withdrawal anxiety in rats. Eur J Pharmacol 2007; 567:211-22. [PMID: 17511983 DOI: 10.1016/j.ejphar.2007.04.025] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2007] [Revised: 04/02/2007] [Accepted: 04/03/2007] [Indexed: 10/23/2022]
Abstract
We have recently shown that the neurosteroid allopregnanolone modulates anxiolytic effect of ethanol. In the present report, we attempted to examine whether neurosteroids progesterone and dehydroepiandrosterone sulphate (DHEAS), which modulate gamma-aminobutyric acid (GABA(A)) receptor function, affects development of tolerance to ethanol anxiolysis and withdrawal anxiety. Rats on ethanol (6% v/v in nutritionally balanced liquid diet) for prolong period (10 days) were injected twice daily either with vehicle, progesterone (a precursor of allopregnanolone, positive GABA(A) receptor modulator), finasteride (5alpha-reductase inhibitor) or DHEAS (negative GABA(A) receptor modulator). During this period, rats were acutely challenged periodically with ethanol (2 g/kg, i.p., 8% w/v) and subjected to the elevated plus maze test. For withdrawal studies, similar treatment protocols (except ethanol challenge) were employed and on day 11, rats were subjected to the elevated plus maze test at different time intervals post-ethanol withdrawal. While progesterone significantly advanced the development of tolerance to ethanol anxiolysis and enhanced withdrawal anxiety, DHEAS and finasteride prevented such behavioral alterations. These data highlight the important role played by GABAergic neurosteroids progesterone and DHEAS in the development of tolerance to ethanol anxiolysis and withdrawal anxiety in rats. Moreover, it points to the potential usefulness of specific neurosteroids as targets in the treatment of alcoholism.
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Affiliation(s)
- Ajaykumar N Sharma
- Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University, Nagpur-440 033, Maharashtra, India
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Marutha Ravindran CR, Mehta AK, Ticku MK. Effect of chronic administration of ethanol on the regulation of tyrosine kinase phosphorylation of the GABAA receptor subunits in the rat brain. Neurochem Res 2007; 32:1179-87. [PMID: 17404840 DOI: 10.1007/s11064-007-9288-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2006] [Accepted: 01/11/2007] [Indexed: 10/23/2022]
Abstract
One of the many pharmacological targets of ethanol is the GABA inhibitory system, and chronic ethanol (CE) is known to alter the polypeptide levels of the GABA(A )receptor subunits in rat brain regions. In the present study, we investigated the regulation of the tyrosine kinase phosphorylation of the GABA(A) receptor alpha(1)-, beta(2)- and gamma(2)-subunits in the rat cerebellum, cerebral cortex and hippocampus following chronic administration of ethanol to the rats. We observed either down-regulation or no change in the tyrosine kinase phosphorylation of the alpha(1) subunit, whereas there was an up-regulation or no change in the case of beta(2)- and gamma(2)-subunits of the GABA(A) receptors depending on the brain region following chronic administration of ethanol to the rats. These changes reverted back to the control level following 48 h of ethanol-withdrawal. These results suggest that tyrosine kinase phosphorylation of GABA(A )receptors may play a significant role in ethanol dependence.
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Affiliation(s)
- C R Marutha Ravindran
- Department of Pharmacology, MC 7764, The University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA
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Mello CF, Rubin MA, Sultana R, Barron S, Littleton JM, Butterfield DA. Difluoromethylornithine decreases long-lasting protein oxidation induced by neonatal ethanol exposure in the hippocampus of adolescent rats. Alcohol Clin Exp Res 2007; 31:887-94. [PMID: 17386069 DOI: 10.1111/j.1530-0277.2007.00369.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Ethanol exposure and withdrawal during central nervous system development can cause oxidative stress and produce severe and long-lasting behavioral and morphological alterations in which polyamines seem to play an important role. However, it is not known if early ethanol exposure causes long-lasting protein oxidative damage and if polyamines play a role in such a deleterious effect of ethanol. METHODS In this study we investigated the effects of early ethanol exposure (6 g/kg/d, by gavage), from postnatal day (PND) 1 to 8, and of the administration of difluoromethylornithine (DFMO, 500 mg/kg, i.p., on PND 8), a polyamine biosynthesis inhibitor, on the extent of oxidative modification of proteins. Indices of oxidative modification of proteins included protein carbonyls, 3-nitrotyrosine (3-NT), and protein bound 4-hydroxynonenal (HNE) in the hippocampus, cerebellum, hypothalamus, striatum, and cerebral cortex of Sprague-Dawley rats at PND 40. RESULTS Both ethanol and DFMO administration alone increased protein carbonyl immunoreactivity in the hippocampus at PND 40, but the combination of DFMO and ethanol resulted in no effect on protein carbonyl levels. No alterations in the content of protein-bound HNE, 3-NT, or carbonyl were found in any other cerebral structure. CONCLUSIONS These results suggest that the hippocampus is selectively affected by early ethanol exposure and by polyamine synthesis inhibition. In addition, the results suggest a role for polyamines in the long-lasting increase of protein carbonyls induced by ethanol exposure and withdrawal.
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Affiliation(s)
- Carlos Fernando Mello
- Departamento de Fisiologia e Farmacologia, Universidade Federal de Santa Maria, Santa Maria, Brazil
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Zhou FC, Anthony B, Dunn KW, Lindquist WB, Xu ZC, Deng P. Chronic alcohol drinking alters neuronal dendritic spines in the brain reward center nucleus accumbens. Brain Res 2007; 1134:148-61. [PMID: 17198693 PMCID: PMC1857312 DOI: 10.1016/j.brainres.2006.11.046] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2006] [Revised: 08/28/2006] [Accepted: 11/03/2006] [Indexed: 02/04/2023]
Abstract
Alcohol is known to affect glutamate transmission. However, how chronic alcohol affects the synaptic structure mediating glutamate transmission is unknown. Repeated alcohol exposure in a subject with familial alcoholic history often leads to alcohol addiction. The current study adopts alcohol-preferring rats, which are known to develop high drinking. Two-photon microscopy analysis indicates that chronic alcohol of 14 weeks either, under continuous alcohol (C-Alc) or with repeated deprivation (RD-Alc), causes dysmorphology--thickened, beaded, and disoriented dendrites that are reminiscent of reactive astrocytes--in a subpopulation of medium spiny neurons. The density of dendritic spines was found differentially lower in the nucleus accumbens of RD-Alc and C-Alc groups as compared with those of Water groups. Large-sized spines and multiple-headed spines were increased in the RD-Alc group. The NMDA receptor subunit NR1 proteins, as analyzed with Western blot, were upregulated in C-Alc, but not in RD-Alc. The upregulated NMDA receptor subunits of NR1 however, are predominantly a splice variant isoform with truncated exon 21, which is required for membrane-bound trafficking or anchoring into a spine synaptic site. These maladaptations may contribute to the transformation of spines. The changes, in density and head-size of spines and the corresponding NMDA receptors, demonstrated an alteration of microcircuitry for glutamate reception. The current study demonstrates for the first time that chronic alcohol exposure causes structural alteration of dendrites and their spines in the key reward brain region in animals that have a genetic background leading to alcohol addiction.
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Affiliation(s)
- Feng C Zhou
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202, USA.
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Abstract
Excitatory NMDA receptors are an important target of ethanol. Chronic ethanol exposure, in vivo and in vitro, increases polypeptide levels of NR1 subunit, the key subunit of functional NMDA receptors. In vitro, chronic ethanol treatment increases the half-life of NR1 mRNA and this observation is dependent on new protein synthesis. The present study was undertaken to locate cis-acting region(s) within the NR1 3'-untranslated region (UTR) and identify NR1 3'-UTR binding trans-acting proteins expressed in mouse fetal cortical neurons. Utilizing RNA gel shift assays we identified a 156-nt cis-acting region that binds to polysomal trans-acting proteins. This binding was highly specific as inclusion of cyclophilin RNA or tRNA did not interfere with cis-trans interactions. Importantly, the 3'-UTR binding activity was significantly up-regulated in the presence of ethanol. UV cross-link analysis detected three NR1 3'-UTR binding proteins and their molecular mass calculated by Northwestern analysis was approximately 88, 60 and 47 kDa, respectively. Northwestern analysis showed a significant up-regulation of the 88-kDa protein after chronic ethanol treatment. The 88-kDa protein was purified and identified by tandem mass spectrometry as the beta subunit of alpha glucosidase II (GIIbeta). That GIIbeta is indeed a trans-acting protein and binds specifically to 3'-UTR of NR1 mRNA was confirmed by RNA gel mobility supershift assays and immuno RT-PCR. Western blotting data established a significant increase of GIIbeta polypeptide in chronic ethanol-exposed fetal cortical neurons. We hypothesize that the identified cis-acting region and the associated RNA-binding proteins are important regulators of NR1 subunit gene expression.
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MESH Headings
- 3' Untranslated Regions/drug effects
- Animals
- Blotting, Northern/methods
- Blotting, Western/methods
- Cells, Cultured
- Central Nervous System Depressants/pharmacology
- Cerebral Cortex/cytology
- Electrophoretic Mobility Shift Assay/methods
- Embryo, Mammalian
- Ethanol/pharmacology
- Immunoprecipitation/methods
- Mice
- Mice, Inbred C57BL
- Neurons/drug effects
- Neurons/physiology
- Protein Binding/drug effects
- Protein Biosynthesis/drug effects
- RNA, Messenger/metabolism
- RNA-Binding Proteins/physiology
- Receptors, N-Methyl-D-Aspartate/genetics
- Receptors, N-Methyl-D-Aspartate/physiology
- Regulatory Sequences, Ribonucleic Acid
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Transcription, Genetic
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Affiliation(s)
- Antje Anji
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA
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Eva C, Oberto A, Mele P, Serra M, Biggio G. Role of brain neuroactive steroids in the functional interplay between the GABA(A) and the NPY-Y1 receptor mediated signals in the amygdala. Pharmacol Biochem Behav 2006; 84:568-80. [PMID: 16824587 DOI: 10.1016/j.pbb.2006.05.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2006] [Accepted: 05/17/2006] [Indexed: 11/18/2022]
Abstract
Various lines of evidence suggest a functional interaction between GABA(A) and Neuropeptide Y (NPY)-Y(1) receptor (Y(1)R) mediated transmissions in various brain regions, which can be important in the regulation of sedation, feeding, anxious behaviour and neuronal excitability. By using a transgenic mouse model carrying the murine Y(1)R gene promoter fused to the lacZ reporter gene (Y(1)R/LacZ mice), we showed that prolonged pharmacologically or physiologically induced changes in the cerebrocortical concentrations of the neuroactive steroids 3alpha-hydroxy-5alpha-pregnan- 20-one (3alpha,5alpha TH PROG) and tetrahydrodeoxycorticosterone (3alpha,5alpha TH DOC) increases Y(1)R/LacZ transgene expression in the central and medial amygdala, an effect similar to that induced by long-term treatment with positive modulators of the GABA(A) receptor complex (diazepam or abecarnil). We also demonstrated that fluctuations in the cerebrocortical concentrations of 3alpha,5alpha-TH PROG and 3alpha,5alpha TH DOC during voluntary ethanol consumption and ethanol withdrawal induces a marked increase in Y(1)R gene expression that becomes apparent 48 h after withdrawal. These data provide evidence that neuroactive steroids may play an important role in the functional interaction between the GABA(A) receptor and NPY-Y(1)R mediated pathways in the amygdala, which might represent an important regulatory mechanism for modulation of several functions, including ethanol withdrawal.
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Affiliation(s)
- Carola Eva
- Dipartimento di Anatomia, Farmacologia e Medicina Legale, Sezione di Farmacologia, Via Pietro Giuria 13, 10125, Università di Torino, Torino, Italy.
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Follesa P, Biggio F, Talani G, Murru L, Serra M, Sanna E, Biggio G. Neurosteroids, GABAA receptors, and ethanol dependence. Psychopharmacology (Berl) 2006; 186:267-80. [PMID: 16163526 DOI: 10.1007/s00213-005-0126-0] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2005] [Accepted: 06/21/2005] [Indexed: 11/26/2022]
Abstract
RATIONALE Changes in the expression of type A receptors for gamma-aminobutyric acid (GABA) represent one of the mechanisms implicated in the development of tolerance to and dependence on ethanol. The impact of such changes on the function and pharmacological sensitivity of GABAA receptors (GABAARs) has remained unclear, however. Certain behavioral and electrophysiological actions of ethanol are mediated by an increase in the concentration of neuroactive steroids in the brain that results from stimulation of the hypothalamic-pituitary-adrenal (HPA) axis. Such steroids include potent modulators of GABAAR function. OBJECTIVES We have investigated the effect of ethanol exposure and withdrawal on subunit expression and receptor function evaluated by subunit selective compounds, as well as the effects of short-term exposure to ethanol on both neurosteroid synthesis and GABAAR function, in isolated neurons and brain tissue. RESULTS Chronic treatment with and subsequent withdrawal from ethanol alter the expression of genes for specific GABAAR subunits in cultured rat neurons, and these changes are associated with alterations in receptor function and pharmacological sensitivity to neurosteroids, zaleplon, and flumazenil. Acute ethanol exposure increases the amount of 3alpha-hydroxy-5alpha-pregnan-20-one (allopregnanolone) in hippocampal slices by a local action independent of the activity of the HPA axis. This effect of ethanol was associated with an increased amplitude of GABAAR-mediated miniature inhibitory postsynaptic currents recorded from CA1 pyramidal neurons in such slices. CONCLUSIONS Chronic ethanol exposure elicits changes in the subunit composition of GABAARs, which, in turn, likely contribute to changes in receptor function associated with the altered pharmacological and behavioral sensitivity characteristic of ethanol tolerance and dependence. Ethanol may also modulate GABAAR function by increasing the de novo synthesis of neurosteroids in the brain in a manner independent of the HPA axis. This latter mechanism may play an important role in the central effects of ethanol.
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Affiliation(s)
- Paolo Follesa
- Department of Experimental Biology Bernardo Loddo, University of Cagliari, Cagliari, 09123, Italy
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Zhou FC, Sahr RN, Sari Y, Behbahani K. Glutamate and dopamine synaptic terminals in extended amygdala after 14-week chronic alcohol drinking in inbred alcohol-preferring rats. Alcohol 2006; 39:39-49. [PMID: 16938628 DOI: 10.1016/j.alcohol.2006.06.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2005] [Revised: 04/18/2006] [Accepted: 06/22/2006] [Indexed: 11/20/2022]
Abstract
Alcohol has been shown to affect glutamate (GLU) and dopamine (DA) release and their correlated receptors in the key reward center--extended amygdala--which includes the shell of nucleus accumbens (sNAc) and central nucleus of amygdala (cAmg). It is unclear to date whether there is an alteration in the number of presynaptic GLU/DA nerve terminals. In this study, we investigated the number of GLU and DA terminals in the extended amygdala of alcohol-preferring (P) rats that chronically drank ethanol. P rats have a propensity to drink ethanol to intoxication and develop an alcohol dependency. The P rats were divided into (1) Water group given ad libitum chow and water for 14 weeks; (2) Continuous alcohol group (C-Alc) given ad libitum chow and choice of 15 or 30% (v/v) ethanol or water for 14 weeks; and (3) Repeated deprivation (RD-Alc) group given the same choice of ethanol or water for 6 weeks, followed by a twice repeated cycle of 2 weeks without ethanol followed by 2 weeks with ethanol. Two subpopulations of GLU terminals were labeled by immunostaining for the vesicular GLU transporter 1 (vGLUT1) and vesicular GLU transporter 2 (vGLUT2). DA terminals were labeled by immunostaining for tyrosine hydroxylase (TH). The GLU and DA immunostained (im) varicosities were quantified and analyzed using stereological methods. We found that chronic alcohol did not alter the number of TH-im terminals in the extended amygdala in either the C-Alc or RD-Alc drinking paradigms. Thus, the increases in extracellular levels of DA previously reported following chronic alcohol are likely due to a change in the efficiency of DA release rather than a change in the number of DA terminals. The number of vGLUT1-im terminals was also unchanged in the extended amygdala; however, the number of vGLUT2-im terminals, which represent the greater population of GLU terminals, was increased in the sNAc of the RD-Alc group compared to the Water group. Chronic alcohol is known to affect GLU release, and our findings indicate that repeated alcohol deprivation may preferentially increase GLU terminals in the sNAc bearing the vGLUT2, which are primarily afferents from the thalamus. Our results further indicate that repeated deprivation of alcohol can change the ratio of GLU to DA innervation in the sNAc, a key region of the reward circuitry.
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Affiliation(s)
- Feng C Zhou
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202, USA.
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47
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Chandler LJ, Carpenter-Hyland E, Hendricson AW, Maldve RE, Morrisett RA, Zhou FC, Sari Y, Bell R, Szumlinski KK. Structural and functional modifications in glutamateric synapses following prolonged ethanol exposure. Alcohol Clin Exp Res 2006; 30:368-76. [PMID: 16441286 PMCID: PMC1512148 DOI: 10.1111/j.1530-0277.2006.00041.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
This article summarizes the proceedings of a symposium presented at the 2005 annual meeting of the Research Society on Alcoholism in Santa Barbara, California, USA. The organizer and chair was L. Judson Chandler. The presentations were (1) Chronic Ethanol Exposure, N-Methyl-D-Aspartate (NMDA) Receptor Dynamics, and Withdrawal Hyperexcitability, by Adam Hendricson, Regina Maldve, and Richard Morrisett; (2) Ethanol-Induced Synaptic Targeting of NMDA Receptors Is Associated With Enhanced Postsynaptic Density-95 Clustering and Spine Size, by Judson Chandler and Ezekiel Carpenter-Hyland; (3) Presynaptic and Postsynaptic Alterations in the Nucleus Accumbens Following Chronic Alcohol Exposure, by Feng Zhou, Youssef Sari, and Richard Bell; and (4) An Active Role for Accumbens Homer2 Expression in Alcohol-Induced Neural Plasticity, by Karen Szumlinski.
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Affiliation(s)
- L Judson Chandler
- Alcohol Research Center and Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
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Affiliation(s)
- George F Koob
- Molecular and Integrative Neurosciences Department, The Scripps Research Institute, La Jolla, California, USA
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Nelson TE, Ur CL, Gruol DL. Chronic intermittent ethanol exposure enhances NMDA-receptor-mediated synaptic responses and NMDA receptor expression in hippocampal CA1 region. Brain Res 2005; 1048:69-79. [PMID: 15919065 DOI: 10.1016/j.brainres.2005.04.041] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2004] [Revised: 04/14/2005] [Accepted: 04/15/2005] [Indexed: 11/21/2022]
Abstract
In previous studies, we found that chronic intermittent ethanol (CIE) treatment-a model of ethanol consumption in which animals are exposed to and withdrawn from intoxicating levels of ethanol on a daily basis-produces neuroadaptive changes in hippocampal area CA1 excitatory synaptic transmission and plasticity. Synaptic responses mediated by N-methyl-D-aspartate (NMDA) receptors are known to be sensitive to ethanol and could play an important role in the neuroadaptive changes induced by CIE treatment. To address this issue, we compared electrophysiological recordings of pharmacologically isolated NMDA-receptor-mediated field excitatory postsynaptic potentials (fEPSPs) in the CA1 region of hippocampal slices prepared from control rats and rats exposed to 2 weeks of CIE treatment administered by vapor inhalation. We found that fEPSPs induced by NMDA receptor activation were unaltered in slices prepared shortly after cessation of CIE treatment (i.e., < or = 1 day of withdrawal from CIE). However, following 7 days of withdrawal from CIE treatment, NMDA-receptor-mediated fEPSPs were augmented relative to age-matched controls. Western blot analysis of NMDA receptor subunit expression showed that, at 7 days of withdrawal, the level of protein for NR2A and NR2B subunits was elevated in the CA1 region of hippocampal slices from CIE-treated animals compared with slices from age-matched controls. These results are consistent with an involvement of NMDA-receptor-mediated synaptic responses in the neuroadaptive effects of CIE on hippocampal physiology and suggest that such changes may contribute to ethanol-induced changes in processes dependent on NMDA-receptor-mediated synaptic responses such as learning and memory, neural development, hyperexcitability and seizures, and neurotoxicity.
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Affiliation(s)
- T E Nelson
- Department of Neuropharmacology, CVN-11, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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Bitran D, Solano SM. Termination of pseudopregnancy in the rat alters the response to progesterone, chlordiazepoxide, and MK-801 in the elevated plus-maze. Psychopharmacology (Berl) 2005; 180:447-54. [PMID: 15700179 DOI: 10.1007/s00213-005-2194-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2004] [Accepted: 01/12/2005] [Indexed: 10/25/2022]
Abstract
RATIONALE Allopregnanolone, a neurosteroid-reduced metabolite of progesterone, is a well-documented positive modulator of the gamma-aminobutyric type A (GABA(A)) receptor. As has been reported for other positive modulators of the GABA(A) receptor, chronic exposure to neurosteroids is hypothesized to decrease GABA(A) receptor function. Drawing from the literature on chronic exposure to benzodiazepines or alcohol, putative changes in N-methyl-D-aspartate (NMDA) receptor function are also expected after chronic neurosteroid exposure. OBJECTIVES To assess the sensitivity of the GABA(A) and NMDA receptors after chronic elevation of neurosteroid produced by termination of pseudopregnancy in behavioral tests of anxiety and sensorimotor coordination. METHODS Female rats ovariectomized on day 10 of pseudopregnancy were tested in the elevated plus-maze and on the rotor rod after an acute injection of progesterone (4 mg/0.2 ml, s.c.), chlordiazepoxide (5 or 15 mg/kg, i.p.), or MK-801 (0.025, 0.05, or 0.1 mg/kg, i.p.). RESULTS Pseudopregnancy termination produced an anxiogenic-like response in the plus-maze; an acute injection of progesterone restored baseline levels of behavior in this test. Pseudopregnancy termination eliminated the anxiolytic-like, sedative, and ataxic effects of chlordiazepoxide. In contrast, pseudopregnancy termination produced an increased sensitivity to the anxiolytic-like and ataxic effects of MK-801. CONCLUSIONS The effects of pseudopregnancy termination on the behavioral response to positive modulators of the GABA(A) receptor are consistent with results from studies in which chronic exposure to neurosteroids decreases the response to acute neurosteroid and benzodiazepine administration. However, unlike the enhanced glutamatergic tone resulting from discontinuation of chronic benzodiazepine or alcohol exposure, the termination of pseudopregnancy apparently decreases NMDA receptor function.
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Affiliation(s)
- Daniel Bitran
- Department of Psychology, College of the Holy Cross, 1 College Street, Worcester, MA 01610, USA.
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