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Castle ME, Flanigan ME. The role of brain serotonin signaling in excessive alcohol consumption and withdrawal: A call for more research in females. Neurobiol Stress 2024; 30:100618. [PMID: 38433994 PMCID: PMC10907856 DOI: 10.1016/j.ynstr.2024.100618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 02/01/2024] [Accepted: 02/14/2024] [Indexed: 03/05/2024] Open
Abstract
Alcohol Use Disorder (AUD) is a leading cause of death and disability worldwide, but current treatments are insufficient in fully addressing the symptoms that often lead to relapses in alcohol consumption. The brain's serotonin system has been implicated in AUD for decades and is a major regulator of stress-related behaviors associated with increased alcohol consumption. This review will discuss the current literature on the association between neurobiological adaptations in serotonin systems and AUD in humans as well as the effectiveness of serotonin receptor manipulations on alcohol-related behaviors like consumption and withdrawal. We will further discuss how these findings in humans relate to findings in animal models, including a comparison of systemic pharmacological manipulations modulating alcohol consumption. We next provide a detailed overview of brain region-specific roles for serotonin and serotonin receptor signaling in alcohol-related behaviors in preclinical animal models, highlighting the complexity of forming a cohesive model of serotonin function in AUD and providing possible avenues for more effective therapeutic intervention. Throughout the review, we discuss what is known about sex differences in the sequelae of AUD and the role of serotonin in these sequelae. We stress a critical need for additional studies in women and female animals so that we may build a clearer path to elucidating sex-specific serotonergic mechanisms and develop better treatments.
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Affiliation(s)
- Megan E. Castle
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA
| | - Meghan E. Flanigan
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA
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2
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Meyer C, Schoettner K, Amir S. The effects of circadian desynchronization on alcohol consumption and affective behavior during alcohol abstinence in female rats. Front Behav Neurosci 2022; 16:1044783. [PMID: 36620855 PMCID: PMC9813852 DOI: 10.3389/fnbeh.2022.1044783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 12/02/2022] [Indexed: 12/24/2022] Open
Abstract
Disruption of circadian rhythmicity distorts physiological and psychological processes and has major consequences on health and well-being. A chronic misalignment within the internal time-keeping system modulates alcohol consumption and contributes to stress-related psychiatric disorders which are known to trigger alcohol misuse and relapse. While there is growing evidence of the deleterious impact of circadian disruption on male physiology and behavior, knowledge about the effect in females remains limited. The present study aims to fill the gap by assessing the relationship between internal desynchronization and alcohol intake behavior in female rats. Female Wistar rats kept under standard 24-h, 22-h light-dark conditions, or chronic 6-h advanced phase shifts, were given intermittent access to 20% alcohol followed by an extended alcohol deprivation period. Alcohol consumption under altered light-dark (LD) conditions was assessed and emotional behavior during alcohol abstinence was evaluated. Internally desynchronization in female rats does not affect alcohol consumption but alters scores of emotionality during alcohol abstinence. Changes in affective-like behaviors were accompanied by reduced body weight gain and estrous irregularities under aberrant LD conditions. Our data suggest that internal desynchronization caused by environmental factors is not a major factor contributing to the onset and progression of alcohol abuse, but highlights the need of maintaining circadian hygiene as a supportive remedy during alcohol rehabilitation.
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Kantar D, Acun AD, Er H, Afsar E, Yargıcoglu P. Anxiolytic-like effects of extremely low frequency electric field in stressed rats: involvement of 5-HT2C receptors. Int J Radiat Biol 2022; 99:1473-1482. [PMID: 35675556 DOI: 10.1080/09553002.2022.2087929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 05/03/2022] [Accepted: 05/22/2022] [Indexed: 10/18/2022]
Abstract
BACKGROUND Possible modulatory effects of noninvasive brain stimulation have gained interest recently. In our study, the effect of low frequency electric fields (LF-EF) on stress-induced electrophysiological, behavioral changes and the possible involvement of serotonergic 5-HT2C receptors were investigated. MATERIALS AND METHODS A total of eight groups including the control groups were formed by applying LF-EF with or without a 5-HT2C receptor agonist to naïve or acute stress exposed rats to demonstrate the effects of LF-EF. LF-EF administration at 10 kV/m was started 30 min before acute stress application and lasted for 1 h in total. Anxiety levels and social interaction were evaluated using the elevated plus maze test and social interaction test, respectively. Auditory evoked potentials (AEP) were recorded by using ascending loudness paradigms. Loudness dependence AEP (LDAEP) was calculated by using amplitude values to analyze serotonergic transmission. Serotonin and glucocorticoid levels were measured in the frontal cortex and hippocampus. RESULTS It was observed that the applied LF-EF reduced the anxiety behavior, and attenuated the LDAEP responses in stress and/or 5-HT2C receptor agonist applied groups. In parallel, an increase in serotonin levels and a decrease in glucocorticoid levels were observed. However, LF-EF exposure was ineffective in impaired social interaction. CONCLUSIONS Our findings show that 10 kV/m LF-EF administration may modulate the neural network and physiological responses associated with mild acute stress. 5-HT2C receptor dependent functions are thought to play a role in the anxiolytic effect of LF-EF.
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Affiliation(s)
- Deniz Kantar
- Department of Biophysics, Faculty of Medicine, Akdeniz University, Antalya, Turkey
| | - Alev Duygu Acun
- Department of Biophysics, Faculty of Medicine, Akdeniz University, Antalya, Turkey
| | - Hakan Er
- Department of Medical Imaging Techniques, Vocational School of Health Services, Akdeniz University, Antalya, Turkey
| | - Ebru Afsar
- Department of Nutrition and Dietetics, Faculty of Health Sciences, Istanbul Kültür University, Istanbul, Turkey
| | - Piraye Yargıcoglu
- Department of Biophysics, Faculty of Medicine, Akdeniz University, Antalya, Turkey
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Pomrenze MB, Paliarin F, Maiya R. Friend of the Devil: Negative Social Influences Driving Substance Use Disorders. Front Behav Neurosci 2022; 16:836996. [PMID: 35221948 PMCID: PMC8866771 DOI: 10.3389/fnbeh.2022.836996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 01/13/2022] [Indexed: 11/20/2022] Open
Abstract
Substance use disorders in humans have significant social influences, both positive and negative. While prosocial behaviors promote group cooperation and are naturally rewarding, distressing social encounters, such as aggression exhibited by a conspecific, are aversive and can enhance the sensitivity to rewarding substances, promote the acquisition of drug-taking, and reinstate drug-seeking. On the other hand, withdrawal and prolonged abstinence from drugs of abuse can promote social avoidance and suppress social motivation, accentuating drug cravings and facilitating relapse. Understanding how complex social states and experiences modulate drug-seeking behaviors as well as the underlying circuit dynamics, such as those interacting with mesolimbic reward systems, will greatly facilitate progress on understanding triggers of drug use, drug relapse and the chronicity of substance use disorders. Here we discuss some of the common circuit mechanisms underlying social and addictive behaviors that may underlie their antagonistic functions. We also highlight key neurochemicals involved in social influences over addiction that are frequently identified in comorbid psychiatric conditions. Finally, we integrate these data with recent findings on (±)3,4-methylenedioxymethamphetamine (MDMA) that suggest functional segregation and convergence of social and reward circuits that may be relevant to substance use disorder treatment through the competitive nature of these two types of reward. More studies focused on the relationship between social behavior and addictive behavior we hope will spur the development of treatment strategies aimed at breaking vicious addiction cycles.
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Affiliation(s)
- Matthew B. Pomrenze
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, United States
- *Correspondence: Matthew B. Pomrenze Rajani Maiya
| | - Franciely Paliarin
- Department of Physiology, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - Rajani Maiya
- Department of Physiology, Louisiana State University Health Sciences Center, New Orleans, LA, United States
- *Correspondence: Matthew B. Pomrenze Rajani Maiya
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Dos Santos LC, Junqueira Ayres DD, de Sousa Pinto ÍA, Silveira MA, Albino MDC, Holanda VAD, Lima RH, André E, Padovan CM, Gavioli EC, de Paula Soares V. Early and late behavioral consequences of ethanol withdrawal: focus on brain indoleamine 2,3 dioxygenase activity. Alcohol 2021; 90:1-9. [PMID: 33031882 DOI: 10.1016/j.alcohol.2020.09.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 09/15/2020] [Accepted: 09/28/2020] [Indexed: 12/18/2022]
Abstract
Anxiety and depression are symptoms associated with ethanol withdrawal that lead individuals to relapse. In the kynurenine pathway, the enzyme indoleamine 2,3 dioxygenase (IDO) is responsible for the conversion of tryptophan to kynurenine, and dysregulation of this pathway has been associated with psychiatric disorders, such as anxiety and depression. The present study evaluated the early and late behavioral and biochemical effects of ethanol withdrawal in rats. Male Wistar rats were submitted to increasing concentrations of ethanol in drinking water during 21 days. In experiment 1, both control and withdrawal groups were submitted to a battery of behavioral tests 3, 5, 10, 19, and 21 days following ethanol removal. In experiment 2, animals were euthanized 3 days (short-term) or 21 days (long-term) after withdrawal, and the brains were dissected altogether, following kynurenine concentration analysis in prefrontal cortex, hippocampus, and striatum. Short-term ethanol withdrawal decreased the exploration of the open arms in the elevated plus-maze. In the forced swimming test, long-term ethanol-withdrawn rats displayed higher immobility time than control animals. Ethanol withdrawal altered neither locomotion nor motor coordination of rats. In experiment 2, kynurenine concentrations were increased in the prefrontal cortex after a long-term period of withdrawal. In conclusion, short-term ethanol withdrawal produced anxiety-like behaviors, while long-term withdrawal favored depressive-like behaviors. Long-term ethanol withdrawal elevated kynurenine levels, specifically in the prefrontal cortex, suggesting that the depressive-like responses observed after long-term withdrawal might be related to the increased IDO activity.
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Affiliation(s)
- Luana Carla Dos Santos
- Laboratory of Psychopharmacology, Department of Biophysics and Pharmacology, Biosciences Center, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Décio Dutra Junqueira Ayres
- Laboratory of Behavioral Pharmacology, Department of Biophysics and Pharmacology, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Ícaro Aleksei de Sousa Pinto
- Laboratory of Psychopharmacology, Department of Biophysics and Pharmacology, Biosciences Center, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Marana Ali Silveira
- Laboratory of Psychopharmacology, Department of Biophysics and Pharmacology, Biosciences Center, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Maryelle de Cássia Albino
- Laboratory of Psychopharmacology, Department of Biophysics and Pharmacology, Biosciences Center, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Victor Anastácio Duarte Holanda
- Laboratory of Behavioral Pharmacology, Department of Biophysics and Pharmacology, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Ramón Hypolito Lima
- Graduate Program in Neuroengineering, Edmond and Lily Safra International Institute for Neuroscience, Macaiba, RN, Brazil
| | - Eunice André
- Department of Pharmacology, Federal University of Parana, Curitiba, PR, Brazil
| | - Cláudia Maria Padovan
- Department of Psychology, Faculty of Philosophy Science and Letters of Ribeirão Preto, University of São Paulo, SP, Brazil
| | - Elaine Cristina Gavioli
- Laboratory of Behavioral Pharmacology, Department of Biophysics and Pharmacology, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Vanessa de Paula Soares
- Laboratory of Psychopharmacology, Department of Biophysics and Pharmacology, Biosciences Center, Federal University of Rio Grande do Norte, Natal, RN, Brazil.
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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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7
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Belmer A, Patkar OL, Lanoue V, Bartlett SE. 5-HT1A receptor-dependent modulation of emotional and neurogenic deficits elicited by prolonged consumption of alcohol. Sci Rep 2018; 8:2099. [PMID: 29391482 PMCID: PMC5794771 DOI: 10.1038/s41598-018-20504-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 01/19/2018] [Indexed: 12/13/2022] Open
Abstract
Repeated episodes of binge-like alcohol consumption produce anxiety, depression and various deleterious effects including alterations in neurogenesis. While the involvement of the serotonin receptor 1 A (5-HT1A) in the regulation of anxiety-like behavior and neurogenesis is well documented, its contribution to alcohol withdrawal-induced anxiety and alcohol-induced deficits in neurogenesis is less documented. Using the Drinking-In-the-Dark (DID) paradigm to model chronic long-term (12 weeks) binge-like voluntary alcohol consumption in mice, we show that the selective partial activation of 5-HT1A receptors by tandospirone (3 mg/kg) prevents alcohol withdrawal-induced anxiety in a battery of behavioral tests (marble burying, elevated-plus-maze, open-field), which is accompanied by a robust decrease in binge-like ethanol intake (1 and 3 mg/kg). Furthermore, using triple immunolabelling of proliferation and neuronal differentiation markers, we show that long-term DID elicits profound deficits in neurogenesis and neuronal fate specification in the dorsal hippocampus that are entirely reversed by a 2-week chronic treatment with the 5-HT1A partial agonist tandospirone (3 mg/kg/day). Together, our results confirm previous observations that 5-HT1A receptors play a pivotal role in alcohol drinking behavior and the associated emotional and neurogenic impairments, and suggest that 5-HT1A partial agonists represent a promising treatment strategy for alcohol abuse.
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Affiliation(s)
- Arnauld Belmer
- Translational Research Institute, Queensland University of Technology, Brisbane, 4100, Australia
- Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, 4100, Brisbane, Australia
| | - Omkar L Patkar
- Translational Research Institute, Queensland University of Technology, Brisbane, 4100, Australia
- Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, 4100, Brisbane, Australia
| | - Vanessa Lanoue
- Clem Jones Centre for Ageing Dementia Research (CJCADR), Queensland Brain Institute, University of Queensland, Brisbane, 4100, Australia
| | - Selena E Bartlett
- Translational Research Institute, Queensland University of Technology, Brisbane, 4100, Australia.
- Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, 4100, Brisbane, Australia.
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8
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Kleczkowska P, Smaga I, Filip M, Bujalska-Zadrozny M. Are Alcohol Anti-relapsing and Alcohol Withdrawal Drugs Useful in Cannabinoid Users? Neurotox Res 2016; 30:698-714. [PMID: 27484692 DOI: 10.1007/s12640-016-9655-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 07/22/2016] [Accepted: 07/22/2016] [Indexed: 11/27/2022]
Abstract
Cannabinoids are still classified as illegal psychoactive drugs despite their broad and increasingly acknowledged therapeutic potential. These substances are most famous for their wide recreational use, particularly among young adults to either alter the state of consciousness, intensify pleasure induced by other psychoactive substances or as an alternative to the previously abused drugs. It is important to emphasize that cannabinoids are often taken together with a variety of medications intended for the treatment of alcohol use disorder (AUD) or alcohol withdrawal syndrome (AWS). These medications include disulfiram, acamprosate, and naltrexone. In this paper, we summarize recent advances in the knowledge of possible beneficial effects and interactions between cannabinoids and drugs commonly used for treatment of AUD and AWS either comorbid or existing as a separate disorder.
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Affiliation(s)
- Patrycja Kleczkowska
- Department of Pharmacodynamics, Centre for Preclinical Research and Technology, Medical University of Warsaw, 1B Banacha Str, 02-097, Warsaw, Poland.
| | - Irena Smaga
- Faculty of Pharmacy, Medical College, Jagiellonian University, Medyczna 9, 30-688, Kraków, Poland
| | - Małgorzata Filip
- Laboratory of Drug Addiction Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343, Kraków, Poland
| | - Magdalena Bujalska-Zadrozny
- Department of Pharmacodynamics, Centre for Preclinical Research and Technology, Medical University of Warsaw, 1B Banacha Str, 02-097, Warsaw, Poland
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9
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Belmer A, Patkar OL, Pitman KM, Bartlett SE. Serotonergic Neuroplasticity in Alcohol Addiction. Brain Plast 2016; 1:177-206. [PMID: 29765841 PMCID: PMC5928559 DOI: 10.3233/bpl-150022] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Alcohol addiction is a debilitating disorder producing maladaptive changes in the brain, leading drinkers to become more sensitive to stress and anxiety. These changes are key factors contributing to alcohol craving and maintaining a persistent vulnerability to relapse. Serotonin (5-Hydroxytryptamine, 5-HT) is a monoamine neurotransmitter widely expressed in the central nervous system where it plays an important role in the regulation of mood. The serotonin system has been extensively implicated in the regulation of stress and anxiety, as well as the reinforcing properties of all of the major classes of drugs of abuse, including alcohol. Dysregulation within the 5-HT system has been postulated to underlie the negative mood states associated with alcohol use disorders. This review will describe the serotonergic (5-HTergic) neuroplastic changes observed in animal models throughout the alcohol addiction cycle, from prenatal to adulthood exposure. The first section will focus on alcohol-induced 5-HTergic neuroadaptations in offspring prenatally exposed to alcohol and the consequences on the regulation of stress/anxiety. The second section will compare alterations in 5-HT signalling induced by acute or chronic alcohol exposure during adulthood and following alcohol withdrawal, highlighting the impact on the regulation of stress/anxiety signalling pathways. The third section will outline 5-HTergic neuroadaptations observed in various genetically-selected ethanol preferring rat lines. Finally, we will discuss the pharmacological manipulation of the 5-HTergic system on ethanol- and anxiety/stress-related behaviours demonstrated by clinical trials, with an emphasis on current and potential treatments.
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Affiliation(s)
- Arnauld Belmer
- Translational Research Institute, Queensland University of Technology, Brisbane, Australia.,Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Australia
| | - Omkar L Patkar
- Translational Research Institute, Queensland University of Technology, Brisbane, Australia.,Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Australia
| | - Kim M Pitman
- Translational Research Institute, Queensland University of Technology, Brisbane, Australia.,Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Australia
| | - Selena E Bartlett
- Translational Research Institute, Queensland University of Technology, Brisbane, Australia.,Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Australia
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10
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Breese GR, Knapp DJ. Persistent adaptation by chronic alcohol is facilitated by neuroimmune activation linked to stress and CRF. Alcohol 2016; 52:9-23. [PMID: 27139233 PMCID: PMC4855305 DOI: 10.1016/j.alcohol.2016.01.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 12/10/2015] [Accepted: 01/24/2016] [Indexed: 01/11/2023]
Abstract
This review updates the conceptual basis for the association of alcohol abuse with an insidious adaptation that facilitates negative affect during withdrawal from chronic intermittent alcohol (CIA) exposure - a change that later supports sensitization of stress-induced anxiety following alcohol abstinence. The finding that a CRF1-receptor antagonist (CRF1RA) minimized CIA withdrawal-induced negative affect supported an association of alcohol withdrawal with a stress mechanism. The finding that repeated stresses or multiple CRF injections into selected brain sites prior to a single 5-day chronic alcohol (CA) exposure induced anxiety during withdrawal provided critical support for a linkage of CIA withdrawal with stress. The determination that CRF1RA injection into positive CRF-sensitive brain sites prevented CIA withdrawal-induced anxiety provided support that neural path integration maintains the persistent CIA adaptation. Based upon reports that stress increases neuroimmune function, an effort was undertaken to test whether cytokines would support the adaptation induced by stress/CA exposure. Twenty-four hours after withdrawal from CIA, cytokine mRNAs were found to be increased in cortex as well as other sites in brain. Further, repeated cytokine injections into previously identified brain sites substituted for stress and CRF induction of anxiety during CA withdrawal. Discovery that a CRF1RA prevented the brain cytokine mRNA increase induced by CA withdrawal provided critical evidence for CRF involvement in this neuroimmune induction after CA withdrawal. However, the CRF1RA did not block the stress increase in cytokine mRNA increases in controls. The latter data supported the hypothesis that distinct mechanisms linked to stress and CA withdrawal can support common neuroimmune functions within a brain site. As evidence evolves concerning neural involvement in brain neuroimmune function, a better understanding of the progressive adaptation associated with CIA exposure will advance new knowledge that could possibly lead to strategies to combat alcohol abuse.
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Affiliation(s)
- George R Breese
- Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7178, USA; Department of Pharmacology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7178, USA; Department of Psychiatry, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7178, USA; Curriculum in Neurobiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7178, USA; The UNC Neuroscience Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7178, USA.
| | - Darin J Knapp
- Bowles Center for Alcohol Studies, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7178, USA; Department of Psychiatry, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7178, USA
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11
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Marcinkiewcz CA. Serotonergic Systems in the Pathophysiology of Ethanol Dependence: Relevance to Clinical Alcoholism. ACS Chem Neurosci 2015; 6:1026-39. [PMID: 25654315 DOI: 10.1021/cn5003573] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Alcoholism is a progressive brain disorder that is marked by increased sensitivity to the positive and negative reinforcing properties of ethanol, compulsive and habitual use despite negative consequences, and chronic relapse to alcohol drinking despite repeated attempts to reduce intake or abstain from alcohol. Emerging evidence from preclinical and clinical studies implicates serotonin (5-hydroxytryptamine; 5-HT) systems in the pathophysiology of alcohol dependence, suggesting that drugs targeting 5-HT systems may have utility in the treatment of alcohol use disorders. In this Review, we discuss the role of 5-HT systems in alcohol dependence with a focus on 5-HT interactions with neural circuits that govern all three stages of the addiction cycle. We attempt to clarify how 5-HT influences circuit function at these different stages with the goal of identifying neural targets for pharmacological treatment of this debilitating disorder.
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Affiliation(s)
- Catherine A. Marcinkiewcz
- Bowles Center for
Alcohol
Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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12
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Functional alterations in the dorsal raphe nucleus following acute and chronic ethanol exposure. Neuropsychopharmacology 2015; 40:590-600. [PMID: 25120075 PMCID: PMC4289946 DOI: 10.1038/npp.2014.205] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 08/08/2014] [Accepted: 08/09/2014] [Indexed: 02/05/2023]
Abstract
Alcoholism is a pervasive disorder perpetuated in part to relieve negative mood states like anxiety experienced during alcohol withdrawal. Emerging evidence demonstrates a role for the serotonin-rich dorsal raphe (DR) in anxiety following ethanol withdrawal. The current study examined the effects of chronic ethanol vapor exposure on the DR using slice electrophysiology in male DBA2/J mice. We found that chronic ethanol exposure resulted in deficits in social approach indicative of increased anxiety-like behavior at both 24 h and 7 days post-ethanol exposure. At 24 h post-ethanol exposure, we observed increased excitability and decreased spontaneous inhibitory transmission (inhibitory postsynaptic currents, IPSCs) in the DR. At 7 days post-ethanol exposure, we observed increased spontaneous and miniature excitatory transmission (excitatory postsynaptic currents, EPSCs). Because acute ethanol alters GABA transmission in other brain regions, we assessed the effects of ex vivo ethanol (50 mM) on miniature IPSCs (mIPSCs) in the DR 24-h post-ethanol exposure. Bath application of ethanol enhanced the amplitude of mIPSCs in cells from ethanol-naive and chronic intermittent ethanol-exposed (CIE) mice, but significantly enhanced the frequency of mIPSCs only in cells from CIE mice, suggesting that DR neurons are more sensitive to the inhibitory effects of acute ethanol following CIE. On the basis of these findings, we hypothesize that net excitation of DR neurons following chronic ethanol exposure contributes to enhanced anxiety during ethanol withdrawal, and that increased sensitivity of DR neurons to subsequent ethanol exposure may mediate acute ethanol's ability to relieve anxiety during ethanol withdrawal.
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13
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Marcinkiewcz CA, Dorrier CE, Lopez AJ, Kash TL. Ethanol induced adaptations in 5-HT2c receptor signaling in the bed nucleus of the stria terminalis: implications for anxiety during ethanol withdrawal. Neuropharmacology 2015; 89:157-67. [PMID: 25229718 PMCID: PMC4469779 DOI: 10.1016/j.neuropharm.2014.09.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 08/18/2014] [Accepted: 09/02/2014] [Indexed: 01/13/2023]
Abstract
One of the hallmarks of alcohol dependence is the presence of a withdrawal syndrome during abstinence, which manifests as physical craving for alcohol accompanied by subjective feelings of anxiety. Using a model of chronic intermittent ethanol (CIE) vapor in mice, we investigated the role of serotonin2c receptor (5HT2c-R) signaling in the BNST as a neural substrate underlying ethanol-induced anxiety during withdrawal. Mice were subjected to a 5-day CIE regimen of 16 h of ethanol vapor exposure followed by an 8 h "withdrawal" period between exposures. After the 5th and final exposure, mice were withdrawn for 24 h or 1 week before experiments began. Anxiety-like behavior was assessed in the social approach, light dark, and open field tests with mice showing deficits in social, but not general anxiety-like behavior that was alleviated by pretreatment with the 5HT2c-R antagonist SB 242,084 (3 mg/kg, i.p.) 24 h and 1 week post-CIE. Using immunohistochemistry and whole cell patch clamp electrophysiology, we also found that CIE increased FOS-IR and enhanced neuronal excitability in the ventral BNST (vBNST) 24 h into withdrawal in a 5HT2c-R dependent manner. This enhanced excitability persisted for 1 week post-CIE. We also found that mCPP, a 5HT2c/b agonist, induced a more robust depolarization in cells of the vBNST in CIE mice, confirming that 5HT2c-R signaling is upregulated in the vBNST following CIE. Taken together, these results suggest that CIE upregulates 5HT2c-R signaling in the vBNST, leading to increased excitability. This enhanced excitability of the vBNST may drive increased anxiety-like behavior during ethanol withdrawal.
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Affiliation(s)
- Catherine A Marcinkiewcz
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Cayce E Dorrier
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Alberto J Lopez
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Thomas L Kash
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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Kash TL, Pleil KE, Marcinkiewcz CA, Lowery-Gionta EG, Crowley N, Mazzone C, Sugam J, Hardaway JA, McElligott ZA. Neuropeptide regulation of signaling and behavior in the BNST. Mol Cells 2015; 38:1-13. [PMID: 25475545 PMCID: PMC4314126 DOI: 10.14348/molcells.2015.2261] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 09/29/2014] [Indexed: 12/23/2022] Open
Abstract
Recent technical developments have transformed how neuroscientists can probe brain function. What was once thought to be difficult and perhaps impossible, stimulating a single set of long range inputs among many, is now relatively straight-forward using optogenetic approaches. This has provided an avalanche of data demonstrating causal roles for circuits in a variety of behaviors. However, despite the critical role that neuropeptide signaling plays in the regulation of behavior and physiology of the brain, there have been remarkably few studies demonstrating how peptide release is causally linked to behaviors. This is likely due to both the different time scale by which peptides act on and the modulatory nature of their actions. For example, while glutamate release can effectively transmit information between synapses in milliseconds, peptide release is potentially slower [See the excellent review by Van Den Pol on the time scales and mechanisms of release (van den Pol, 2012)] and it can only tune the existing signals via modulation. And while there have been some studies exploring mechanisms of release, it is still not as clearly known what is required for efficient peptide release. Furthermore, this analysis could be complicated by the fact that there are multiple peptides released, some of which may act in contrast. Despite these limitations, there are a number of groups making progress in this area. The goal of this review is to explore the role of peptide signaling in one specific structure, the bed nucleus of the stria terminalis, that has proven to be a fertile ground for peptide action.
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Affiliation(s)
- Thomas L. Kash
- Bowles Center for Alcohol Studies and Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill,
USA
| | - Kristen E. Pleil
- Bowles Center for Alcohol Studies and Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill,
USA
| | - Catherine A. Marcinkiewcz
- Bowles Center for Alcohol Studies and Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill,
USA
| | - Emily G. Lowery-Gionta
- Bowles Center for Alcohol Studies and Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill,
USA
| | - Nicole Crowley
- Bowles Center for Alcohol Studies and Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill,
USA
| | - Christopher Mazzone
- Bowles Center for Alcohol Studies and Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill,
USA
| | - Jonathan Sugam
- Bowles Center for Alcohol Studies and Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill,
USA
| | - J. Andrew Hardaway
- Bowles Center for Alcohol Studies and Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill,
USA
| | - Zoe A. McElligott
- Bowles Center for Alcohol Studies and Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill,
USA
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15
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Kolik LG, Nadorova AV, Kozlovskaya MM. Efficacy of peptide anxiolytic selank during modeling of withdrawal syndrome in rats with stable alcoholic motivation. Bull Exp Biol Med 2014; 157:52-5. [PMID: 24913576 DOI: 10.1007/s10517-014-2490-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Indexed: 10/25/2022]
Abstract
We studied the effects of selank on the development of symptoms of acute 48-h alcohol withdrawal in outbred rats drinking 10 % ethanol as the only source of fluid for 24 weeks. In alcohol-preferring animals (mean daily ethanol intake >5.0 g/kg) allowed free choice between 10 % ethanol and water, single intraperitoneal injection of selank in a dose of 0.3 mg/kg eliminated anxiety induced by ethanol withdrawal in tests elevated plus maze and social interaction tests and prevented the formation of mechanical allodynia without affecting ethanol consumption. The fi ndings suggest that selank is effective in eliminating of alcohol withdrawal symptoms in rats.
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Affiliation(s)
- L G Kolik
- V. V. Zakusov Research Institute of Pharmacology, Russian Academy of Medical Sciences, Moscow, Russia,
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16
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Cheaha D, Sawangjaroen K, Kumarnsit E. Characterization of fluoxetine effects on ethanol withdrawal-induced cortical hyperexcitability by EEG spectral power in rats. Neuropharmacology 2014; 77:49-56. [DOI: 10.1016/j.neuropharm.2013.09.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 08/18/2013] [Accepted: 09/16/2013] [Indexed: 11/29/2022]
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Abstract
Exposure to an uncontrollable stressor elicits a constellation of physiological and behavioral sequel in laboratory rats that often reflect aspects of anxiety and other emotional disruptions. We review evidence suggesting that plasticity within the serotonergic dorsal raphe nucleus (DRN) is critical to the expression of uncontrollable stressor-induced anxiety. Specifically, after uncontrollable stressor exposure subsequent anxiogenic stimuli evoke greater 5-HT release in DRN terminal regions including the amygdala and striatum; and pharmacological blockade of postsynaptic 5-HT(2C) receptors in these regions prevents expression of stressor-induced anxiety. Importantly, the controllability of stress, the presence of safety signals, and a history of exercise mitigate the expression of stressor-induced anxiety. These stress-protective factors appear to involve distinct neural substrates; with stressor controllability requiring the medial prefrontal cortex, safety signals the insular cortex and exercise affecting the 5-HT system directly. Knowledge of the distinct yet converging mechanisms underlying these stress-protective factors could provide insight into novel strategies for the treatment and prevention of stress-related psychiatric disorders.
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Bhorkar AA, Dandekar MP, Nakhate KT, Subhedar NK, Kokare DM. Involvement of the central melanocortin system in the effects of caffeine on anxiety-like behavior in mice. Life Sci 2013; 95:72-80. [PMID: 24361398 DOI: 10.1016/j.lfs.2013.12.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Revised: 12/07/2013] [Accepted: 12/10/2013] [Indexed: 12/12/2022]
Abstract
AIMS To investigate the role of the melanocortin (MC) system in the framework of the central nucleus of the amygdala (CeA) in the differential effects of the adenosine receptor blocker caffeine on anxiety-like behavior, using the social interaction (SI) test. MAIN METHODS Caffeine was injected intraperitoneally, alone or in combination with alpha-melanocyte stimulating hormone (α-MSH), the MC4 receptor agonist RO27-3225 or the antagonist HS014 via the intra-CeA route. The effects of chronic (21 days) caffeine, given alone or concurrently with α-MSH, or RO27-3225, were investigated. The effects of withdrawal of these treatments on SI time were also evaluated. Furthermore, the acute effects of HS014 were investigated in different sets of caffeine-withdrawn mice. KEY FINDINGS Acute injection of caffeine, RO27-3225, or α-MSH produced anxiety-like behavior. Prior treatment with α-MSH, or RO27-3225 potentiated the caffeine-induced anxiety-like behavior. Subchronic treatment with HS014 increased the SI time, which was attenuated by caffeine. Chronic administration of caffeine resulted in tolerance to caffeine's anxiogenic effect, while abrupt discontinuation of the treatment produced peak anxiety-like behavior at 72 h post-withdrawal. Concurrent administration of α-MSH, or RO27-3225 with chronic caffeine delayed the development of tolerance and prevented withdrawal-induced anxiety-like behavior. Moreover, acute treatment with HS014 at 72 h post-withdrawal attenuated the anxiety-like behavior. SIGNIFICANCE α-MSH, possibly via MC4 receptor in the neuroanatomical framework of the CeA, may contribute to the acute, chronic and withdrawal actions of caffeine associated with anxiety-like behavior in the neuroanatomical framework of the CeA.
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Affiliation(s)
- Amita A Bhorkar
- Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University, Nagpur 440 033, Maharashtra, India
| | - Manoj P Dandekar
- Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University, Nagpur 440 033, Maharashtra, India
| | - Kartik T Nakhate
- Rungta College of Pharmaceutical Sciences and Research, Rungta Educational Campus, Kohka-Kurud Road, Bhilai 490 024, Chhattisgarh, India
| | - Nishikant K Subhedar
- Indian Institute of Science Education and Research (IISER), Sai Trinity Building, Sutarwadi, Pashan, Pune 411 021, Maharashtra, India
| | - Dadasaheb M Kokare
- Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University, Nagpur 440 033, Maharashtra, India.
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Kumar J, Hapidin H, Bee YTG, Ismail Z. Effects of the mGluR5 antagonist MPEP on ethanol withdrawal induced anxiety-like syndrome in rats. Behav Brain Funct 2013; 9:43. [PMID: 24279870 PMCID: PMC4222772 DOI: 10.1186/1744-9081-9-43] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 11/23/2013] [Indexed: 11/22/2022] Open
Abstract
Abstinence from chronic ethanol consumption leads to the manifestation of a variety of symptoms attributed to central nervous system hyperexcitability, such as increased irritability, anxiety, and restlessness. Recent studies have demonstrated the importance of metabotropic glutamate receptor 5 (mGluR5) in addictive behaviours. This study investigates the effects of the mGluR5 antagonist 2-methyl-6-(phenylethynyl)-pyridine (MPEP) on ethanol withdrawal induced anxiety using two behavioural paradigms. Male Wistar rats were fed a Modified Liquid Diet (MLD) containing low fat cow milk, sucrose, and maltodextrin with a gradual introduction of 2.4%, 4.8% and 7.2% ethanol for 20 days. Six hours into ethanol withdrawal, the rats were intraperitoneally injected with normal saline and MPEP (2.5, 5.0, 10, 20, 30 mg/kg) and were assessed for ethanol withdrawal induced anxiety-like syndrome using an automated elevated plus maze and an open field. MPEP at 10 mg/kg significantly attenuated ethanol withdrawal induced anxiety without any compromising effects on locomotor activities. Despite reversing several indices of ethanol withdrawal induced anxiety in both the elevated plus maze and the open field, low doses of MPEP (2.5, 5 mg/kg) significantly compromised the locomotor activities of ethanol withdrawn rats. High doses of MPEP (20 and 30 mg/kg) significantly attenuated withdrawal anxiety when tested in the elevated plus maze but not in the open field. Administration of MPEP (2.5, 5, 10, 20, 30 mg/kg) has no significant compromising effect on the locomotor activities of ethanol naïve rats. Despite significantly reducing withdrawal anxiety in both behavioural paradigms at 10 mg/kg, the compromising effects of low and high doses of MPEP must be further explored along with the therapeutic efficiency of this drug for relieving withdrawal induced anxiety.
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Affiliation(s)
- Jaya Kumar
- BRAINetwork Centre for Neurocognitive Science, School of Health Sciences, Health Campus, Universiti Sains Malaysia, Kubang Kerian, Kelantan 16150, Malaysia.
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Vicente MA, Zangrossi H. Involvement of 5-HT2C and 5-HT1A receptors of the basolateral nucleus of the amygdala in the anxiolytic effect of chronic antidepressant treatment. Neuropharmacology 2013; 79:127-35. [PMID: 24275045 DOI: 10.1016/j.neuropharm.2013.11.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 11/12/2013] [Accepted: 11/13/2013] [Indexed: 12/30/2022]
Abstract
Facilitation of serotonin 2C- and 1A-receptor (5-HT2C-R and 5-HT1A-R) mediated neurotransmission in the basolateral nucleus of the amygdala (BLA) has been associated with anxiogenic and anxiolytic effects, respectively. It has been also shown that stimulation of BLA 5-HT2C-Rs underlies the anxiogenic effect caused by acute systemic administration of the antidepressants imipramine or fluoxetine. Here we investigated whether chronic treatment with these two antidepressants, which causes anxiolytic effects, decreases the responsiveness of these receptors in the BLA. We also investigated whether the blockage of 5-HT1A-Rs in the same amygdala nucleus alters the anxiolytic effect of chronic imipramine treatment. The results showed that in male Wistar rats intra-BLA injection of the 5-HT2C-R agonist MK-212 facilitated inhibitory avoidance acquisition in the elevated T-maze and decreased the percentage of time spent by the animals in the lit compartment of the light-dark transition test, indicating an anxiogenic effect. Chronic (21 days) systemic treatment with imipramine (5 or 15 mg/kg) or fluoxetine (10 mg/kg) abolished these effects of MK-212. Acute administration of imipramine (5 mg/kg) failed to interfere with MK-212 effects in both tests. Intra-BLA injection of the 5-HT1A antagonist WAY-100635 blocked the anxiolytic, but not the panicolytic, effect of imipramine in the tests used. Our findings indicate that both a reduction in 5-HT2C-R- and a facilitation of 5-HT1A-R-mediated neurotransmission in the BLA are involved in the anxiolytic effect of antidepressant drugs.
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Affiliation(s)
- Maria Adrielle Vicente
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, 14049-900 Ribeirão Preto, SP, Brazil
| | - Helio Zangrossi
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, 14049-900 Ribeirão Preto, SP, Brazil.
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Abstract
Alcohol is widely consumed; however, excessive use creates serious physical, psychological and social problems and contributes to the pathogenesis of many diseases. Alcohol use disorders (that is, alcohol dependence and alcohol abuse) are maladaptive patterns of excessive drinking that lead to serious problems. Abundant evidence indicates that alcohol dependence (alcoholism) is a complex genetic disease, with variations in a large number of genes affecting a person's risk of alcoholism. Some of these genes have been identified, including two genes involved in the metabolism of alcohol (ADH1B and ALDH2) that have the strongest known affects on the risk of alcoholism. Studies continue to reveal other genes in which variants affect the risk of alcoholism or related traits, including GABRA2, CHRM2, KCNJ6 and AUTS2. As more variants are analysed and studies are combined for meta-analysis to achieve increased sample sizes, an improved picture of the many genes and pathways that affect the risk of alcoholism will be possible.
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Affiliation(s)
- Howard J Edenberg
- Department of Biochemistry, Indiana University School of Medicine, 635 Barnhill Drive, MS4063, Indianapolis, IN 46202-5122, USA.
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22
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Christianson JP, Drugan RC, Flyer JG, Watkins LR, Maier SF. Anxiogenic effects of brief swim stress are sensitive to stress history. Prog Neuropsychopharmacol Biol Psychiatry 2013; 44:17-22. [PMID: 23357538 PMCID: PMC4075115 DOI: 10.1016/j.pnpbp.2013.01.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 01/16/2013] [Accepted: 01/16/2013] [Indexed: 01/29/2023]
Abstract
Stressors that are controllable not only protect an individual from the acute consequences of the stressor, but also the consequences of stressors that occur later. This phenomenon, termed "behavioral immunization", is studied in the rat by first administering tailshocks each of which can be terminated (escapable tailshock) by an instrumental wheel-turn response prior to exposure to a second stressor. Previous research has shown that exposure to escapable tailshock blocks the neurochemical and behavioral consequences of later inescapable tailshock or social defeat stress. Here we explored the generality of behavioral immunization by examining the impact of prior escapable tailshock on the behavioral consequences of cold swim stress. Exposure to a 5min cold-water (19°C) swim caused an anxiety-like reduction in social interaction that was dependent upon 5-HT2C receptor activation. Rats with prior exposure to escapable tailshock did not develop the swim-induced anxiety. Plasticity in the medial prefrontal cortex, a hypothetical neural mechanism underlying behavioral immunization, is discussed.
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Affiliation(s)
- John P. Christianson
- Department of Psychology & Neuroscience, University of Colorado, Boulder, CO 80309, USA, Corresponding author at: Department of Psychology & Neuroscience, Center for Neuroscience, UCB 345, University of Colorado, Boulder, CO 80309-0345, USA. Tel.: +1 860 550 5354; fax: +1 303 492 2967. (J.P. Christianson)
| | - Robert C. Drugan
- Department of Psychology, University of New Hampshire, Durham, NH 03824, USA
| | - Johanna G. Flyer
- Department of Psychology & Neuroscience, University of Colorado, Boulder, CO 80309, USA
| | - Linda R. Watkins
- Department of Psychology & Neuroscience, University of Colorado, Boulder, CO 80309, USA
| | - Steven F. Maier
- Department of Psychology & Neuroscience, University of Colorado, Boulder, CO 80309, USA
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Benyamina A, Naassila M, Bourin M. Potential role of cortical 5-HT(2A) receptors in the anxiolytic action of cyamemazine in benzodiazepine withdrawal. Psychiatry Res 2012; 198:307-12. [PMID: 22421069 DOI: 10.1016/j.psychres.2012.01.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Revised: 12/12/2011] [Accepted: 01/10/2012] [Indexed: 11/19/2022]
Abstract
The antipsychotic cyamemazine is a potent serotonin 5-HT(2A) receptor (5-HT(2AR)) antagonist. A positron emission tomography (PET) study in human patients showed that therapeutic doses of cyamemazine produced near saturation of 5-HT(2AR) occupancy in the frontal cortex, whereas dopamine D(2) occupancy remained below the level for motor side effects observed with typical antipsychotics. Recently, numerous studies have revealed the involvement of 5-HT(2AR) in the pathophysiology of anxiety and a double-blind, randomized clinical trial showed similar efficacy of cyamemazine and bromazepam in reducing the anxiety associated with benzodiazepine withdrawal. Therefore, we reviewed the above articles about 5-HT(2AR) and anxiety in order to understand better the anxiolytic mechanisms of cyamemazine in benzodiazepine withdrawal. The 5-HT(2AR) is the most abundant serotonin receptor subtype in the cortex. Non-pharmacological studies with antisense oligodeoxynucleotides and genetically modified mice clearly showed that cortical 5-HT(2AR) signaling positively modulates anxiety-like behavior. With a few exceptions, most other studies reviewed here further support this view. Therefore, the anxiolytic efficacy of cyamemazine in benzodiazepine withdrawal can be due to a 5-HT(2AR) antagonistic activity at the cortical level.
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Affiliation(s)
- Amine Benyamina
- Inserm U669, University Hospital Paul Brousse, Villejuif, France.
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24
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Serotonin-2C receptors in the basolateral nucleus of the amygdala mediate the anxiogenic effect of acute imipramine and fluoxetine administration. Int J Neuropsychopharmacol 2012; 15:389-400. [PMID: 21733232 DOI: 10.1017/s1461145711000873] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
A growing body of evidence indicates that facilitation of serotonin-2C receptor (5-HT2CR)-mediated neurotransmission in the basolateral nucleus of the amygdala (BLA) is involved in anxiety generation. We investigated here whether BLA 5-HT2CRs exert a differential role in the regulation of defensive behaviours related to generalized anxiety (inhibitory avoidance) and panic (escape) disorders. We also evaluated whether activation of BLA 5-HT2CRs accounts for the anxiogenic effect caused by acute systemic administration of the antidepressants imipramine and fluoxetine. Male Wistar rats were tested in the elevated T-maze after intra-BLA injection of the endogenous agonist 5-HT, the 5-HT2CR agonist MK-212 or the 5-HT2CR antagonist SB-242084. This test allows the measurement of inhibitory avoidance acquisition and escape expression. We also investigated whether intra-BLA administration of SB-242084 interferes with the acute anxiogenic effect caused by imipramine and fluoxetine in the Vogel conflict test, and imipramine in the elevated T-maze. While intra-BLA administration of 5-HT and MK-212 facilitated inhibitory avoidance acquisition, suggesting an anxiogenic effect, SB-242084 had the opposite effect. None of these drugs affected escape performance. Intra-BLA injection of a sub-effective dose of SB-242084 fully blocked the anxiogenic effect caused either by the local microinjection of 5-HT or the systemic administration of imipramine and fluoxetine. Our findings indicate that 5-HT2CRs in BLA are selectively involved in the regulation of defensive behaviours associated with generalized anxiety, but not panic. The results also provide the first direct evidence that activation of BLA 5-HT2CRs accounts for the short-term aversive effect of antidepressants.
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25
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Fernández-Mateos P, Jiménez-Ortega V, Cano Barquilla P, Cardinali DP, Esquifino AI. Discontinuous versus continuous drinking of ethanol in peripubertal rats: effect on 24-hour pattern of hypophyseal-gonadal axis activity and anterior pituitary oxidative stress. Neuroendocrinology 2012; 96:194-203. [PMID: 22286266 DOI: 10.1159/000334963] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 11/09/2011] [Indexed: 12/24/2022]
Abstract
AIMS Discontinuous (weekend) consumption of alcohol is common in adolescents and young adults. This study therefore assesses, in peripubertal male rats, the effect of discontinuous as compared to chronic feeding of ethanol or control liquid diet. METHODS Animals received an ethanol liquid diet (6.2 % w/v) starting on day 35 of life. Every week for 5 weeks, the discontinuous ethanol group received the ethanol diet for 3 consecutive days and the control liquid diet for 4 days. At the 5th week, 24 h after the last ethanol administration to the discontinuously ethanol-treated animals, rats were killed at 4-hour intervals beginning at 09.00 h. Chronically administered rats received the ethanol diet until immediately before study. RESULTS Disrupted 24-hour rhythmicity together with a significant nocturnal increase in plasma luteinizing hormone (LH), testosterone and prolactin (PRL) occurred in the discontinuous ethanol group. Plasma ethanol levels were undetectable at 24 h after the last ethanol treatment. In contrast, after chronic ethanol administration, plasma PRL was increased late in scotophase while LH and testosterone decreased; blood ethanol levels were 2-fold greater than those in discontinuously ethanol-administered rats killed immediately after ethanol withdrawal. Circulating testosterone positively correlated with LH levels in control rats only. Chronic administration of ethanol significantly augmented mean expression of pituitary nitric oxide synthase (NOS)-2, heme oxygenase (HO)-1, Per1 and Per2 genes and disrupted their diurnal rhythmicity. Decreased NOS-1 and NOS-2 expression during scotophase, together with suppression of the rhythm in Per1 and Per2 expression, were found in the discontinuous ethanol group. CONCLUSIONS Abstinence after discontinuous drinking of alcohol in rats, as compared to chronic administration of ethanol, is accompanied by increases of plasma LH and testosterone, a greater PRL response and a less pronounced oxidative damage of the anterior pituitary.
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Affiliation(s)
- Pilar Fernández-Mateos
- Department of Biochemistry and Molecular Biology III, Universidad Complutense, Madrid, Spain
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26
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Effects of a stressor and corticotrophin releasing factor on ethanol deprivation-induced ethanol intake and anxiety-like behavior in alcohol-preferring P rats. Psychopharmacology (Berl) 2011; 218:179-89. [PMID: 21643675 DOI: 10.1007/s00213-011-2366-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 05/20/2011] [Indexed: 02/06/2023]
Abstract
RATIONALE Stress may elevate ethanol drinking and anxiety associated with ethanol drinking. Studies to identify relevant neurobiological substrates are needed. OBJECTIVE To assess roles of brain regions in corticotrophin releasing factor (CRF) effects on stressor-enhanced, ethanol deprivation-induced drinking and anxiety-like behavior. METHODS Ethanol-preferring rats (P rats) were exposed to three cycles of a two-bottle choice paradigm with two 2-day deprivation periods that included 1 h exposure to a restraint stressor. To assess the role of CRF and to identify relevant brain regions, a CRF-1 receptor antagonist (SSR125543; 10 ug) was injected into the nucleus accumbens (NAC), amygdala (Amyg), or dorsal raphe nucleus (DRN) prior to exposure to the restraint stressor. In a second study, CRF (0.5 ug) was injected into one of these regions, or the ventral tegmental area (VTA), or paraventricular nucleus of the hypothalamus (PVN). RESULTS Applying the restraint stressor during deprivation increased voluntary intake and sensitized anxiety-like behavior. Antagonist injection into the NAC prevented increased drinking without affecting anxiety-like behavior, whereas injection into the Amyg or DRN prevented the anxiety-like behavior without affecting drinking. To confirm CRF actions in the stressor effect, CRF was injected into selected brain regions. NAC injections (but not the VTA, Amyg, DRN, or PVN) facilitated drinking but did not change anxiety-like behavior. Injections into the DRN or Amyg (but not PVN or VTA) enhanced anxiety-like behavior. CONCLUSIONS Results emphasize that a restraint stressor elevates ethanol intake and sensitizes ethanol deprivation-induced anxiety-like behavior through CRF1 receptors in the NAC and Amyg/DRN, respectively.
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Uzbay TI. Atypical Antipsychotic Drugs and Ethanol Withdrawal Syndrome: A Review. Alcohol Alcohol 2011; 47:33-41. [DOI: 10.1093/alcalc/agr142] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Conrad KL, Winder DG. Altered anxiety-like behavior and long-term potentiation in the bed nucleus of the stria terminalis in adult mice exposed to chronic social isolation, unpredictable stress, and ethanol beginning in adolescence. Alcohol 2011; 45:585-93. [PMID: 21194878 PMCID: PMC3085602 DOI: 10.1016/j.alcohol.2010.11.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Revised: 10/25/2010] [Accepted: 11/18/2010] [Indexed: 11/28/2022]
Abstract
Alcohol and chronic stress exposure, especially during adolescence, can lead to an increased risk in adulthood of developing alcohol use disorders. To date, however, no study has assessed the potential long-term effects of chronic intermittent and unpredictable ethanol (EtOH) exposure in mice chronically stressed beginning in adolescence on brain function and anxiety-like behaviors in adulthood. In particular, alterations in function of the bed nucleus of the stria terminalis (BNST), a brain region heavily implicated in anxiety-related behaviors and altered plasticity following EtOH exposure, may play a key role in the pathological responses to chronic stress and EtOH. In the present study, adolescent and adult C57Bl/6J mice were exposed to a regimen of chronic social isolation and unpredictable stressors and EtOH (or air [sham]; CSI-CUS-EtOH and CSI-CUS-Sham, respectively) for 8-10 weeks. In adulthood, mice were tested for altered anxiety-like behavior (elevated plus maze [EPM] and modified social interaction [SI] test). Following behavioral testing, mice were reexposed to CSI-CUS-EtOH (and CSI-CUS-Sham for controls) for an additional 3 days. Four to six hours following the final EtOH (or air) exposure, field potential recordings of the dorsal-lateral (dl)BNST were performed. Mice first exposed during adolescence to CSI-CUS-EtOH displayed lower levels of anxiety-like behavior on the EPM compared with mice first exposed to CSI-CUS-EtOH during adulthood and control mice only exposed to CSI-CUS-Sham, regardless of age of first exposure. However, mice first exposed to CSI-CUS-EtOH during adulthood displayed lower levels of anxiety-like behavior on the SI test compared with mice first exposed during adolescence and control CSI-CUS-Sham mice. CSI-CUS-EtOH exposure, regardless of age, produced blunted expression of long-term potentiation (LTP) in the dlBNST compared with CSI-CUS-Sham mice. This study demonstrates age-dependent effects of chronic unpredictable ethanol exposure in chronically stressed mice on anxiety-like behaviors during adulthood. Further, CSI-CUS-EtOH exposure results in blunted LTP expression in the adult dlBNST.
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Affiliation(s)
- Kelly L Conrad
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville TN 37232-0615
| | - Danny G. Winder
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville TN 37232-0615
- Center for Molecular Neuroscience, Vanderbilt University School of Medicine, Nashville TN 37232-0615
- Kennedy Center for Research on Human Development, Vanderbilt University School of Medicine, Nashville TN 37232-0615
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Knapp DJ, Whitman BA, Wills TA, Angel RA, Overstreet DH, Criswell HE, Ming Z, Breese GR. Cytokine involvement in stress may depend on corticotrophin releasing factor to sensitize ethanol withdrawal anxiety. Brain Behav Immun 2011; 25 Suppl 1:S146-54. [PMID: 21377524 PMCID: PMC3138123 DOI: 10.1016/j.bbi.2011.02.018] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 02/27/2011] [Accepted: 02/28/2011] [Indexed: 12/23/2022] Open
Abstract
Stress has been shown to facilitate ethanol withdrawal-induced anxiety. Defining neurobiological mechanisms through which stress has such actions is important given the associated risk of relapse. While CRF has long been implicated in the action of stress, current results show that stress elevates the cytokine TNFα in the rat brain and thereby implicates cytokines in stress effects. In support of this view, prior TNFα microinjection into the central amygdala (CeA) of rats facilitated ethanol withdrawal-induced anxiety-a response that could not be attributed to an increase in plasma corticosterone. To test for a possible interaction between cytokines and CRF, a CRF1-receptor antagonist (SSR125543) administered prior to the repeated administration of TNFα or MCP-1/CCL2 reduced the magnitude of the withdrawal-induced anxiety. This finding provided evidence for cytokine action being dependent upon CRF. Additionally, the sensitizing effect of stress on withdrawal-induced anxiety was reduced by treating the repeated stress exposure prior to ethanol with the MEK inhibitor SL327. Consistent with cytokines having a neuromediator function distinct from a neuroimmune action, TNFα increased firing rate and GABA release from CeA neurons. Thus, an interaction of glial and neuronal function is proposed to contribute to the interaction of stress and chronic ethanol. Interrupting this potential glial-neuronal interaction could provide a novel means by which to alter the development of emotional states induced by stress that predict relapse in the alcoholic.
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Affiliation(s)
- Darin J. Knapp
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC 27599,Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, NC 27599,Department of Curriculum in Neurobiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599,Corresponding Author: Darin J. Knapp, PhD. CB 7178, University of North Carolina, Chapel Hill, NC 27599, ; Phone: 919-966-0505; Fax: 919-966-5679
| | - Buddy A. Whitman
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC 27599,Department of Curriculum in Neurobiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599
| | - Tiffany A. Wills
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC 27599,Department of Curriculum in Neurobiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599
| | - Robert A. Angel
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC 27599
| | - David H. Overstreet
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC 27599,Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, NC 27599
| | - Hugh E. Criswell
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC 27599,Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, NC 27599
| | - Zhen Ming
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC 27599
| | - George R. Breese
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC 27599,Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, NC 27599,Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC 27599,Department of Curriculum in Neurobiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599
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Moya PR, Fox MA, Jensen CL, Laporte JL, French HT, Wendland JR, Murphy DL. Altered 5-HT2C receptor agonist-induced responses and 5-HT2C receptor RNA editing in the amygdala of serotonin transporter knockout mice. BMC Pharmacol 2011; 11:3. [PMID: 21473759 PMCID: PMC3080299 DOI: 10.1186/1471-2210-11-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Accepted: 04/07/2011] [Indexed: 11/21/2022] Open
Abstract
Background The serotonin 5-HT2C receptor (5-HT2CR) is expressed in amygdala, a region involved in anxiety and fear responses and implicated in the pathogenesis of several psychiatric disorders such as acute anxiety and post traumatic stress disorder. In humans and in rodent models, there is evidence of both anxiogenic and anxiolytic actions of 5-HT2C ligands. In this study, we determined the responsiveness of 5-HT2CR in serotonin transporter (SERT) knockout (-/-) mice, a model characterized by increased anxiety-like and stress-responsive behaviors. Results In the three-chamber social interaction test, the 5-HT2B/2C agonist mCPP decreased sociability and sniffing in SERT wildtype (+/+) mice, both indicative of the well-documented anxiogenic effect of mCPP. This 5-HT2C-mediated response was absent in SERT -/- mice. Likewise, in the open field test, the selective 5-HT2C agonist RO 60-0175 induced an anxiogenic response in SERT +/+ mice, but not in SERT -/- mice. Since 5-HT2CR pre-mRNA is adenosine-to-inosine (A-to-I) edited, we also evaluated the 5-HT2CR RNA editing profiles of SERT +/+ and SERT -/- mice in amygdala. Compared to SERT +/+ mice, SERT-/- mice showed a decrease in less edited, highly functional 5-HT2C isoforms, and an increase in more edited isoforms with reduced signaling efficiency. Conclusions These results indicate that the 5-HT2CR in the amygdala of SERT -/- mice has increased RNA editing, which could explain, at least in part, the decreased behavioral responses to 5-HT2C agonists in SERT -/- mice. These alterations in 5-HT2CR in amygdala may be relevant to humans with SERT polymorphisms that alter SERT expression, function, and emotional behaviors.
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Affiliation(s)
- Pablo R Moya
- Laboratory of Clinical Science, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA.
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Celikyurt IK, Kayir H, Ulak G, Erden FB, Ulusoy GK, Uzbay TI. Effects of risperidone, quetiapine and ziprasidone on ethanol withdrawal syndrome in rats. Prog Neuropsychopharmacol Biol Psychiatry 2011; 35:528-36. [PMID: 21168466 DOI: 10.1016/j.pnpbp.2010.12.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Revised: 12/09/2010] [Accepted: 12/09/2010] [Indexed: 10/18/2022]
Abstract
Comorbid substance use in schizophrenic patients is common, and substance dependence is a predictive factor for psychosis. The present study was designed to investigate the effects of risperidone, quetiapine and ziprasidone, atypical antipsychotic drugs, on ethanol withdrawal syndrome (EWS) in rats. Adult male Wistar rats were used in the study. Ethanol (7.2%, v/v) was given to rats via a liquid diet for 21 days. An isocaloric liquid diet without ethanol was given to control rats. Risperidone (1 and 2 mg/kg), quetiapine (8 and 16 mg/kg), ziprasidone (0.5 and 1 mg/kg) and vehicle were injected into rats intraperitoneally at 1.5 and 5.5 h of ethanol withdrawal. At the 2nd, 4th and 6th hours of ethanol withdrawal, rats were observed for 5 min, and withdrawal signs that included locomotor hyperactivity, stereotyped behaviors, abnormal gait and posture, tail stiffness and agitation were recorded or rated. Following the observations at the 6th hour, the rats were tested for audiogenic seizures. All three drugs had some significant inhibitory effects on EWS-induced behavioral signs beginning at the 2nd hour of withdrawal. The drugs also significantly reduced the incidence of audiogenic seizures. Overall, risperidone and quetiapine seemed to be more effective than ziprasidone in ameliorating the withdrawal signs. Doses of the drugs used in the present study did not produce any significant changes in locomotor activities of naïve rats. Our results suggest that risperidone, quetiapine and ziprasidone had beneficial effects on EWS in rats. Thus, these drugs may be helpful for controlling withdrawal signs in ethanol-dependent patients.
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Breese GR, Sinha R, Heilig M. Chronic alcohol neuroadaptation and stress contribute to susceptibility for alcohol craving and relapse. Pharmacol Ther 2011; 129:149-71. [PMID: 20951730 PMCID: PMC3026093 DOI: 10.1016/j.pharmthera.2010.09.007] [Citation(s) in RCA: 199] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Accepted: 09/08/2010] [Indexed: 01/17/2023]
Abstract
Alcoholism is a chronic relapsing disorder. Major characteristics observed in alcoholics during an initial period of alcohol abstinence are altered physiological functions and a negative emotional state. Evidence suggests that a persistent, cumulative adaptation involving a kindling/allostasis-like process occurs during the course of repeated chronic alcohol exposures that is critical for the negative symptoms observed during alcohol withdrawal. Basic studies have provided evidence for specific neurotransmitters within identified brain sites being responsible for the negative emotion induced by the persistent cumulative adaptation following intermittent-alcohol exposures. After an extended period of abstinence, the cumulative alcohol adaptation increases susceptibility to stress- and alcohol cue-induced negative symptoms and alcohol seeking, both of which can facilitate excessive ingestion of alcohol. In the alcoholic, stressful imagery and alcohol cues alter physiological responses, enhance negative emotion, and induce craving. Brain fMRI imaging following stress and alcohol cues has documented neural changes in specific brain regions of alcoholics not observed in social drinkers. Such altered activity in brain of abstinent alcoholics to stress and alcohol cues is consistent with a continuing ethanol adaptation being responsible. Therapies in alcoholics found to block responses to stress and alcohol cues would presumably be potential treatments by which susceptibility for continued alcohol abuse can be reduced. By continuing to define the neurobiological basis of the sustained alcohol adaptation critical for the increased susceptibility of alcoholics to stress and alcohol cues that facilitate craving, a new era is expected to evolve in which the high rate of relapse in alcoholism is minimized.
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Affiliation(s)
- George R Breese
- Bowles Center for Alcohol Research and the UNC Neuroscience Center, UNC School Of Medicine, Chapel Hill, NC 27599, USA.
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Paterson NE. Translational research in addiction: toward a framework for the development of novel therapeutics. Biochem Pharmacol 2011; 81:1388-407. [PMID: 21216239 DOI: 10.1016/j.bcp.2010.12.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 12/13/2010] [Accepted: 12/15/2010] [Indexed: 12/16/2022]
Abstract
The development of novel substance use disorder (SUD) therapeutics is insufficient to meet the medical needs of a growing SUD patient population. The identification of translatable SUD models and tests is a crucial step in establishing a framework for SUD therapeutic development programs. The present review begins by identifying the clinical features of SUDs and highlights the narrow regulatory end-point required for approval of a novel SUD therapeutic. A conceptual overview of dependence is provided, followed by identification of potential intervention targets in the addiction cycle. The main components of the addiction cycle provide the framework for a discussion of preclinical models and their clinical analogs, all of which are focused on isolated behavioral end-points thought to be relevant to the persistence of compulsive drug use. Thus, the greatest obstacle to successful development is the gap between the multiplicity of preclinical and early clinical end-points and the regulatory end-point of sustained abstinence. This review proposes two pathways to bridging this gap: further development and validation of the preclinical extended access self-administration model; inclusion of secondary end-points comprising all of the measures highlighted in the present discussion in Phase 3 trials. Further, completion of the postdictive validation of analogous preclinical and clinical assays is of high priority. Ultimately, demonstration of the relevance and validity of a variety of end-points to the ultimate goal of abstinence will allow researchers to identify truly relevant therapeutic mechanisms and intervention targets, and establish a framework for SUD therapeutic development that allows optimal decision-making and resource allocation.
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Affiliation(s)
- Neil E Paterson
- Behavioral Pharmacology, PsychoGenics, Inc., 765 Old Saw Mill River Rd., Tarrytown, NY 10591, USA.
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Lorenz RA, Jackson CW, Saitz M. Adjunctive Use of Atypical Antipsychotics for Treatment-Resistant Generalized Anxiety Disorder. Pharmacotherapy 2010; 30:942-51. [DOI: 10.1592/phco.30.9.942] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Wills TA, Knapp DJ, Overstreet DH, Breese GR. Interactions of stress and CRF in ethanol-withdrawal induced anxiety in adolescent and adult rats. Alcohol Clin Exp Res 2010; 34:1603-12. [PMID: 20586753 DOI: 10.1111/j.1530-0277.2010.01245.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Repeated stress or administration of corticotropin-releasing factor (CRF) prior to ethanol exposure sensitizes anxiety-like behavior in adult rats. Current experiments determined whether adolescent rats were more sensitive to these challenges in sensitizing ethanol withdrawal-induced anxiety and altering CRF levels in brain during withdrawal. METHODS Male adult and adolescent Sprague-Dawley rats were restraint stressed (1 hour) twice 1 week apart prior to a single 5-day cycle of ethanol diet (ED; stress/withdrawal paradigm). Other rats received control diet (CD) and three 1-hour restraint stress sessions. Rats were then tested 5, 24, or 48 hours after the final withdrawal for anxiety-like behavior in the social interaction (SI) test. In other experiments, adolescent rats were given two microinjections of CRF icv 1 week apart followed by 5 days of either CD or ED and tested in social interaction 5 hours into withdrawal. Finally, CRF immunoreactivity was measured in the central nucleus of the amygdala (CeA) and paraventricular nucleus (PVN) after rats experienced control diet, repeated ethanol withdrawals, or stress/withdrawal. RESULTS Rats of both ages had reduced SI following the stress/withdrawal paradigm, and this effect recovered within 24 hours. Higher CRF doses were required to reduce SI in adolescents than previously reported in adults. CRF immunohistochemical levels were higher in the PVN and CeA of CD-exposed adolescents. In adolescent rats, repeated ethanol withdrawals decreased CRF in the CeA but was not associated with decreased CRF cell number. There was no change in CRF from adult treatments. CONCLUSIONS In the production of anxiety-like behavior, adolescent rats have equal sensitivity with stress and lower sensitivity with CRF compared to adults. Further, adolescents had higher basal levels of CRF within the PVN and CeA and reduced CRF levels following repeated ethanol withdrawals. This reduced CRF within the CeA could indicate increased release of CRF, and future work will determine how this change relates to behavior.
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Affiliation(s)
- Tiffany A Wills
- Neurobiology Curriculum, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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Logan RW, Seggio JA, Robinson SL, Richard GR, Rosenwasser AM. Circadian wheel-running activity during withdrawal from chronic intermittent ethanol exposure in mice. Alcohol 2010; 44:239-44. [PMID: 20682191 DOI: 10.1016/j.alcohol.2010.02.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Revised: 01/14/2010] [Accepted: 02/10/2010] [Indexed: 01/19/2023]
Abstract
Alcohol withdrawal is associated with affective-behavioral disturbances in both human alcoholics and in animal models. In general, these phenomena are potentiated by increased alcohol exposure duration and by prior withdrawal episodes. Previous studies have also reported locomotor hypoactivity during ethanol withdrawal in rats and mice, but only in novel test environments and not in the home cage. In the present study, we examined the effects of withdrawal from chronic intermittent ethanol (CIE) vapor exposure on the level and circadian periodicity of wheel-running activity in C57BL/6J mice. CIE treatment resulted in reductions in wheel-running activity compared with plain-air controls that persisted for about 1 week after withdrawal. Analysis of circadian waveforms indicated that reduced activity occurred throughout the night phase, but that daily-activity patterns were otherwise unaltered. CIE failed to alter free-running circadian period or phase in animals maintained under constant darkness. These results show that ethanol withdrawal can result in locomotor hypoactivity even in the habitual, home-cage environment, and suggest that withdrawal-related reductions in wheel-running activity may reflect the specific motivational significance of this behavior.
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Witt ED. Research on alcohol and adolescent brain development: opportunities and future directions. Alcohol 2010; 44:119-24. [PMID: 20113880 DOI: 10.1016/j.alcohol.2009.08.011] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Revised: 07/08/2009] [Accepted: 08/06/2009] [Indexed: 12/19/2022]
Abstract
In the past 15 years, both human and animal studies have advanced our understanding of the effects of adolescent alcohol exposure on behavioral and neural development, particularly in the areas of the ontogeny of initial sensitivity and tolerance to alcohol, the consequences of adolescent alcohol exposure on subsequent drinking patterns, as well as cognitive and neural function. Despite these advances, there are still substantial gaps in our understanding of whether heavy adolescent drinking interferes with normal brain development at the cellular and molecular level, and if so, how these changes may translate into patterns of brain connectivity that result in the emergence of alcohol use disorders. This article discusses our current knowledge of the cellular and molecular brain changes that stem from heavy alcohol exposure, including binge patterns, during adolescence. Progress has been made in linking the behavioral effects of adolescent drinking to underlying cellular and molecular mechanisms. However, it is suggested that future research on the etiology and consequences of adolescent drinking use an integrative approach to this problem by combining multiple levels, including genetic, cellular and molecular, systems (neuroimaging), and behavioral, with an emphasis on integrating the different levels of analysis.
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Gilpin NW, Smith AD, Cole M, Weiss F, Koob GF, Richardson HN. Operant behavior and alcohol levels in blood and brain of alcohol-dependent rats. Alcohol Clin Exp Res 2009; 33:2113-23. [PMID: 19740131 PMCID: PMC2789881 DOI: 10.1111/j.1530-0277.2009.01051.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND The purpose of the present investigation was to more clearly define blood-alcohol parameters associated with alcohol dependence produced by alcohol vapor inhalation and alcohol-containing liquid diet. METHODS Alcohol levels in blood and brain were compared during and after 4 hours of acute alcohol vapor exposure; also, brain-alcohol levels were assessed in alcohol-exposed (14-day alcohol vapor) and alcohol-naïve rats during and after 4 hours of acute alcohol vapor exposure. A separate group of rats were implanted with i.v. catheters, made dependent on alcohol via vapor inhalation, and tested for operant alcohol responding; blood-alcohol levels (BALs) were measured throughout operant alcohol drinking sessions during alcohol withdrawal. A final group of rats consumed an alcohol-liquid diet until they were dependent, and those rats were then tested for operant behavior at various withdrawal time points; BALs were measured at different withdrawal time points and after operant sessions. RESULTS Blood- and brain-alcohol levels responded similarly to vapor, but brain-alcohol levels peaked at a higher point and more slowly returned to zero in alcohol-naïve rats relative to alcohol-exposed rats. Alcohol vapor exposure also produced an upward shift in subsequent operant alcohol responding and resultant BALs. Rats consumed large quantities of alcohol-liquid diet, most of it during the dark cycle, sufficient to produce high blood-alcohol levels and elevated operant alcohol responding when tested during withdrawal from liquid diet. CONCLUSIONS These results emphasize that the key determinants of excessive alcohol drinking behavior are the BAL range and pattern of chronic high-dose alcohol exposure.
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Affiliation(s)
- Nicholas W Gilpin
- Committee on Neurobiology of Addictive Disorders, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037, USA.
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Overstreet DH, Fredericks K, Knapp D, Breese G, McMichael J. Nerve growth factor (NGF) has novel antidepressant-like properties in rats. Pharmacol Biochem Behav 2009; 94:553-60. [PMID: 19945476 DOI: 10.1016/j.pbb.2009.11.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Revised: 11/09/2009] [Accepted: 11/22/2009] [Indexed: 10/20/2022]
Abstract
Nerve growth factor, a neurotrophin, may have other functions, including a role in depressive disorders. The present study sought to determine whether NGF would (1) have antidepressant-like effects and (2) behave similarly to or differently from other well-recognized antidepressants. Over a broad dose-range, NGF reduced the exaggerated swim test immobility exhibited by the Flinders Sensitive Line (FSL) rats, but at a standard dose of 40 ng/ml, it was not as effective as desipramine (DMI, 5 mg/kg). The low social interaction behavior and locomotor activity of the FSL rats were less affected by NGF than was the immobility. Acute treatment with NGF did not induce c-fos expression in brain regions known to be activated by other acute antidepressants. The fact that chronic treatment with DMI blunted the corticosterone response to fluoxetine was replicated in this study. However, chronic treatment with NGF did not alter this response. Similarly, chronic treatment with fluoxetine blunted 5-HT(1A) and 5-HT(2A) receptor-mediated responses, whereas chronic treatment with NGF was without effect. Thus, NGF has antidepressant-like effects but does not appear to have biochemical actions typical of other antidepressants.
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Affiliation(s)
- David H Overstreet
- Department of Psychiatry, University of North Carolina at Chapel Hill, CB #7178, Chapel Hill, NC 27599-7178, USA.
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Huang MM, Overstreet DH, Knapp DJ, Angel R, Wills TA, Navarro M, Rivier J, Vale W, Breese GR. Corticotropin-releasing factor (CRF) sensitization of ethanol withdrawal-induced anxiety-like behavior is brain site specific and mediated by CRF-1 receptors: relation to stress-induced sensitization. J Pharmacol Exp Ther 2009; 332:298-307. [PMID: 19843974 DOI: 10.1124/jpet.109.159186] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
In abstinent alcoholics, stress induces negative affect-a response linked to craving and relapse. In rats, repeated stresses at weekly intervals before 5-day ethanol diet sensitize withdrawal-induced anxiety-like behavior ("anxiety") that is blocked by a corticotrophin-releasing factor 1 (CRF-1)-receptor antagonist. Current experiments were performed to identify brain sites that support CRF involvement in stress sensitization of ethanol withdrawal-induced anxiety-like behavior. First, different doses of CRF microinjected weekly into the central amygdala (CeA) before ethanol exposure produced a dose-related sensitization of anxiety during ethanol withdrawal. Subsequently, CRF microinjection into the basolateral amygdala, dorsal raphe nucleus (DRN), or dorsal bed nucleus of the stria terminalis (d-BNST) also sensitized ethanol withdrawal-induced anxiety. In contrast, sensitization of ethanol withdrawal-induced anxiety was not observed after weekly CRF administration into the ventral-BNST, CA1-hippocampal region, or hypothalamic-paraventricular nucleus. Then, experiments documented the CRF receptor subtype responsible for CRF and stress sensitization of withdrawal-induced anxiety. Systemic administration of a CRF-1 receptor antagonist before CRF microinjection into the CeA, DRN, or d-BNST prevented CRF-induced sensitization of anxiety during ethanol withdrawal. Furthermore, repeated microinjections of urocortin-3, a CRF-2 receptor agonist, into the CRF-positive sites did not sensitize anxiety after withdrawal from ethanol. Finally, microinjection of a CRF-1 receptor antagonist into the CeA, DRN, or d-BNST before stress blocked sensitization of anxiety-like behavior induced by the repeated stress/ethanol withdrawal protocol. These results indicate that CRF released by stress acts on CRF-1 receptors within specific brain regions to produce a cumulative adaptation that sensitizes anxiety-like behavior during withdrawal from chronic ethanol exposure.
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Affiliation(s)
- Mae M Huang
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7178, USA
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Overstreet DH, Knapp DJ, Breese GR, Diamond I. A selective ALDH-2 inhibitor reduces anxiety in rats. Pharmacol Biochem Behav 2009; 94:255-61. [PMID: 19747934 DOI: 10.1016/j.pbb.2009.09.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Revised: 08/27/2009] [Accepted: 09/01/2009] [Indexed: 10/20/2022]
Abstract
CVT-10216 is a highly selective, reversible inhibitor of ALDH-2 that reduces excessive alcohol drinking. Anxiety plays a role in alcoholism. The present study asks whether CVT-10216 has anxiolytic properties, as reflected in social interaction behavior in four unrelated rodent models: endogenous anxiety-like behavior in naïve Fawn-Hooded rats, repeated alcohol-withdrawal-induced anxiety, restraint stress-induced anxiety and drug-induced anxiety. CVT-10216 counteracted anxiety in all models except that produced by the 5-HT(2C) agonist, mCPP. CVT-10216 exhibited both acute and prophylactic inhibitions of repeated alcohol-withdrawal-induced anxiety. Importantly, anxiogenic behavior induced by the benzodiazepine receptor inverse agonist, DMCM, was counteracted dose-dependently by CVT-10216. Thus, a non-addictive selective inhibitor of ALDH-2 has both anxiolytic and antidipsotropic properties, which may be dependent, in part on the involvement of the GABA-benzodiazepine system.
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Affiliation(s)
- David H Overstreet
- Bowles Center for Alcohol Studies, Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7178, United States.
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Wills TA, Knapp DJ, Overstreet DH, Breese GR. Sensitization, duration, and pharmacological blockade of anxiety-like behavior following repeated ethanol withdrawal in adolescent and adult rats. Alcohol Clin Exp Res 2008; 33:455-63. [PMID: 19120055 DOI: 10.1111/j.1530-0277.2008.00856.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Repeated ethanol withdrawal sensitizes anxiety-like behavior in adult rats and causes anxiety-like behavior and decreased seizure thresholds in adolescent rats. Current experiments determined if adolescent rats exhibit sensitized anxiety-like behavior, the duration of this effect, if drug pretreatments blocked these effects, and if these effects differed from those seen in adults. METHODS Male adolescent rats received three 5-day cycles of 2.5% ethanol diet (ED) separated by two 2-day withdrawal periods, continuous 15 days of 2.5%ED, or a single 5-day cycle of 2.5%ED. Male adult rats received three 5-day cycles of either 2.5% or 3.5%ED. These groups were tested 5 hours into the final withdrawal for social interaction (SI) deficits (an index of anxiety-like behavior). Ethanol intake was monitored throughout and blood concentrations were obtained from separate groups of rats. Additionally, adolescent rats were tested for SI 1, 2, 7, 14, and 18 days and adults 1 and 2 days after the final withdrawal. Some adolescent rats were also pretreated with the CRF(1) antagonist CP-154,526, the 5-HT(1A) agonist buspirone, or the benzodiazepine receptor antagonist flumazenil during the first 2 withdrawals. RESULTS SI was reduced in adolescent rats following repeated withdrawals of 2.5%ED while neither a continuous or single cycle ED exposure caused this effect. Adult rats also had reduced SI following repeated withdrawals from both 2.5% and 3.5%ED. This effect was present up to 1 week following the final withdrawal in adolescents but returned to baseline by 1 day in adults. CP-154,526, buspirone, or flumazenil prevented this reduction in SI in adolescent rats. CONCLUSIONS Adolescent rats exhibit sensitized anxiety-like behavior following repeated withdrawals at ED concentrations similar to those used in adults. However, this effect is longer lasting in adolescent rats. Drugs modulating CRF, 5-HT, or GABA systems during initial withdrawals prevent the development of anxiety-like behavior otherwise manifest during a final withdrawal in adolescent rats.
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Affiliation(s)
- Tiffany A Wills
- Neurobiology Curriculum, University of North Carolina, School of Medicine, Chapel Hill, North Carolina 27599, USA
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He J, Overstreet DH, Crews FT. Abstinence from moderate alcohol self-administration alters progenitor cell proliferation and differentiation in multiple brain regions of male and female P rats. Alcohol Clin Exp Res 2008; 33:129-38. [PMID: 19076732 DOI: 10.1111/j.1530-0277.2008.00823.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Acute and chronic ethanol exposure has been found to decrease hippocampal neurogenesis, reduce dendritic differentiation of new neurons, and increase cell death. Interestingly, abstinence from such treatment increases hippocampal neurogenesis and microglial genesis across several brain regions. The goal of the current investigation was to study cellular alterations on neuro- and cell-genesis during abstinence following alcohol self-administration using alcohol-preferring rats (P rats). METHODS Male and female P rats were given the choice of drinking 10% alcohol in water or pure water for 7 weeks. Social interaction behavioral assessments were conducted at 5 hours upon removal of alcohol, followed by bromo-deoxyuridine (BrdU, 150 mg/kg x 1/d x 14 d) injections to label proliferating cells. Animals were then killed 4 weeks later to conduct immunohistochemical and confocal analyses using antibodies against BrdU and other phenotypic markers (NeuN for mature neurons; Iba-1 for microglia; GFAP for astrocytes; and NG(2) for oligodendrocyte progenitors). RESULTS Mild alcohol withdrawal anxiety was detected by reduction in social interactions. The number of hippocampal BrdU(+) cells was increased approximately 50% during alcohol abstinence (26 +/- 2.8 in controls vs. 39 +/- 4 in alcohol group). BrdU(+) cells were also increased in the substantia nigra (SN) approximately 65% in the alcohol abstinent group (12 +/- 1 in controls vs. 19 +/- 1.5 in alcohol group). No gender differences were found. Confocal analyses indicated that approximately 75% of co-localization of BrdU(+) cells with NeuN in the hippocampal dentate gyrus (DG) resulting a net increase in neurogenesis in the alcohol abstinent group compared to controls. In cingulum, greater proportion of BrdU(+) cells were co-localized with NG(2) in the alcohol abstinent group indicating increased differentiation toward oligodendrocyte progenitors in both genders. However, the phenotype of the BrdU(+) cells in SN and other brain regions were not identified by NeuN, Iba-1, GFAP, or NG(2) suggesting that these BrdU(+) cells probably remain in a nondifferentiated stage. CONCLUSIONS These data indicate that abstinence from moderate alcohol drinking increases hippocampal neurogenesis, cingulate NG(2) differentiation, and SN undifferentiated cell proliferation in both males and females. Such cellular alteration during abstinence could contribute to the spontaneous partial restoration of cognitive deficits upon sobriety.
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Affiliation(s)
- Jun He
- Bowles Center for Alcohol Studies, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7178, USA
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Wills TA, Knapp DJ, Overstreet DH, Breese GR. Differential dietary ethanol intake and blood ethanol levels in adolescent and adult rats: effects on anxiety-like behavior and seizure thresholds. Alcohol Clin Exp Res 2008; 32:1350-60. [PMID: 18540921 DOI: 10.1111/j.1530-0277.2008.00709.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Adult rats exhibit increased anxiety-like behavior after exposure to repeated cycles of chronic ethanol and withdrawal. While adolescent rats have differential responses to both acute and chronic ethanol treatments, the potential differences in the effects of repeated withdrawals in this population have yet to be determined. METHODS Male adult and adolescent rats received three 5-day cycles of either a 4.5% or 7% ethanol diet (ED) separated by two 2-day withdrawal periods. Five hours into the final withdrawal, rats were tested for social interaction (SI) deficits (an index of anxiety-like behavior) and then assessed for seizure thresholds (audiogenic and bicuculline-induced). Ethanol intake was monitored throughout, and blood ethanol concentrations (BEC) were obtained from a separate group of rats. RESULTS Adolescent rats have reduced SI during the final withdrawal from either ED and exhibit a greater reduction in SI compared to adult rats when exposed to a 7%ED. Audiogenic seizures were not increased during withdrawal from either ED in adult rats, but adolescent rats that received 7%ED displayed increased seizures. The bicuculline seizure thresholds were decreased in both ages exposed to a 7%ED, but only adolescent rats showed this decreased threshold after 4.5%ED. Ethanol intakes and BECs were higher in adolescent rats compared to similarly treated adults. However, ethanol intakes and BECs were comparable between 4.5%ED-treated adolescent and 7%ED-treated adult rats. CONCLUSIONS Behavioral results from the 7%ED-treated groups suggested that adolescent rats may be more vulnerable to repeated withdrawals from ethanol than adults; however, differences in ethanol intake and BECs may be at least in part responsible. When ethanol intakes and BECs were similar between 4.5%ED-treated adolescent and 7%ED-treated adult rats, behavioral effects were not different. Importantly, these data illustrated that adolescent rats can exhibit anxiety and reduced seizure thresholds following this repeated withdrawal paradigm.
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Affiliation(s)
- Tiffany A Wills
- Neurobiology Curriculum, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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Breese GR, Knapp DJ, Overstreet DH, Navarro M, Wills TA, Angel RA. Repeated lipopolysaccharide (LPS) or cytokine treatments sensitize ethanol withdrawal-induced anxiety-like behavior. Neuropsychopharmacology 2008; 33:867-76. [PMID: 17551540 PMCID: PMC2268634 DOI: 10.1038/sj.npp.1301468] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Previous investigations demonstrated that repeated stresses before an ethanol exposure sensitize ethanol withdrawal-induced anxiety-like behavior ('anxiety'). In addition to activating the hypothalamic-pituitary-adrenal axis, acute stress also elevates cytokines in brain. Initially, to test possible cytokine involvement in this stress/withdrawal protocol, cytokines were increased in brain with 2 weekly repeated lipopolysaccharide (LPS) administrations (1000 microg/kg) [corrected] (LPS/withdrawal protocol) or with twice weekly intracerebroventricular (i.c.v.) administrations of the cytokines IL-1 beta, CCL2 (MCP-1) or TNFalpha (cytokine/withdrawal protocol) before exposure and withdrawal from a 5-day cycle of chronic ethanol diet. Both protocols sensitized withdrawal-induced anxiety and confirm cytokine involvement in the sensitized anxiety response. Testing of various doses of LPS (16-1000 microg/kg) and TNFalpha (3-100 ng, i.c.v.) demonstrated the dose-related nature of these protocols to sensitize withdrawal-induced anxiety. The sensitized anxiety was not produced by a single 5-day ethanol diet cycle or by repeated LPS or cytokine treatments alone. Likewise, sensitized anxiety in these protocols could not be attributed to differences in ethanol ingestion. When challenged with a subsequent re-exposure to a 5-day ethanol diet cycle 16 days after completion of the LPS/withdrawal or cytokine/withdrawal protocols, an increase in withdrawal-induced anxiety was observed-an indication of induction of an underlying persistent adaptive change. Finally, just as found previously with the stress/withdrawal protocol, administration of the benzodiazepine receptor antagonist flumazenil before the LPS or TNF treatments prevented anxiety sensitization. Together, these findings indicate that increased cytokine activity induces adaptive change that supports sensitization of ethanol withdrawal-induced anxiety that may be linked to GABA(A)-receptor function.
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Affiliation(s)
- George R Breese
- Department of Psychiatry, UNC School of Medicine, Chapel Hill, NC, USA.
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Knapp DJ, Overstreet DH, Angel RA, Navarro M, Breese GR. The amygdala regulates the antianxiety sensitization effect of flumazenil during repeated chronic ethanol or repeated stress. Alcohol Clin Exp Res 2007; 31:1872-82. [PMID: 17908266 PMCID: PMC2864652 DOI: 10.1111/j.1530-0277.2007.00514.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
BACKGROUND The benzodiazepine receptor antagonist flumazenil reduces anxiety-like behavior and sensitization of anxiety-like behavior in various models of ethanol withdrawal in rodents. The mechanism and brain region(s) that account for this action of flumazenil remain unknown. This investigation explored the potential role of several brain regions (amygdala, raphe, inferior colliculus, nucleus accumbens, and paraventricular hypothalamus) for these actions of flumazenil. METHODS Rats were surgically implanted with guide cannulae directed over the brain region of interest and then treated with an ethanol diet for three 7-day dietary cycles (5 days on ethanol diet followed by 2 days on control diet). At approximately 4 hours, flumazenil was administered intracranially into each of the first 2 withdrawals. Examinations of anxiety-like behavior followed 1 week later during a third withdrawal. In other animals, restraint stress sessions or intra-amygdala DMCM (methyl-6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate) injections, preceded by intraperitoneal flumazenil injections, were substituted for the first 2 ethanol treatment cycles to assess the potential anxiety-sensitizing action of stress or a benzodiazepine receptor inverse agonist, respectively. RESULTS Flumazenil treatment of the amygdala during the first 2 withdrawals blocked the development of sensitized anxiety seen during a third withdrawal. Similar actions of flumazenil were found when stress sessions substituted for the first 2 cycles of ethanol exposure and withdrawal. Amygdala treatment with DMCM magnified the anxiety response to the single subthreshold chronic ethanol treatment, and prophylactic flumazenil blocked this effect. CONCLUSIONS Intra-amygdala flumazenil inhibits the development of anxiety sensitized by repeated ethanol withdrawal, stress/ethanol withdrawal, or DMCM/ethanol withdrawal. These actions suggest that site-specific and persistent effects of flumazenil on gamma-aminobutyric acid-modulatory processes in this brain region are relevant to sensitized behavioral effects seen in alcoholism.
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Affiliation(s)
- Darin J Knapp
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7158, USA.
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Overstreet DH, Knapp DJ, Breese GR. Drug challenges reveal differences in mediation of stress facilitation of voluntary alcohol drinking and withdrawal-induced anxiety in alcohol-preferring P rats. Alcohol Clin Exp Res 2007; 31:1473-81. [PMID: 17624999 PMCID: PMC3010749 DOI: 10.1111/j.1530-0277.2007.00445.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND There is controversy over whether exposure to stress precipitates relapse and/or increases alcohol (ethanol) intake. Our laboratory has demonstrated that repeated stress prior to withdrawal from a brief forced exposure to alcohol results in withdrawal-induced anxiety-like behavior. Because anxiety is often regarded as a precipitating factor in relapsing alcoholics, we decided to examine the consequences of stressing alcohol-preferring P rats on both voluntary alcohol drinking and withdrawal-induced anxiety. METHODS P rats were subjected to 3 cycles of 5 days of voluntary alcohol drinking and 2 days of deprivation. Restraint stress (60 min) was applied to some animals during the first and second deprivations/withdrawals (at 4 h). Drugs (flumazenil, buspirone, SB242,084, CP154,526, CRA1000, naloxone, haloperidol, olanzapine, naloxone, and haloperidol) were given to some rats 30 min prior to restraint stress. RESULTS Stressed, deprived P rats exhibited both a longer duration of elevated alcohol drinking and anxiety-like behavior in the social interaction test upon withdrawal after the third cycle of voluntary alcohol drinking. When given prior to each of the restraint stresses, the benzodiazepine receptor antagonist flumazenil (5 mg/kg), the corticotrophin releasing factor receptor antagonists CRA1000 (3 mg/kg) and CP154,526 (10 mg/kg), the serotonin 5-HT(1A) receptor partial agonist buspirone (0.6 mg/kg), and the mixed 5-HT(2C)/D2 receptor antagonist olanzapine were effective in reducing the increased duration of elevated alcohol drinking and the withdrawal-induced anxiety-like behavior. In contrast, while the opiate receptor antagonist naloxone (20 mg/kg), the 5-HT(2C) receptor antagonist SB242084 (3 mg/kg), and the dopamine receptor antagonist haloperidol (0.1 mg/kg) also reduced drinking, they did not significantly alter anxiety like behavior. CONCLUSION These results suggest that stress-induced facilitation of alcohol drinking and withdrawal-induced anxiety-like behavior in P rats may be closely but imperfectly linked.
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Affiliation(s)
- David H Overstreet
- Department of Psychiatry, Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7178, USA.
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Knapp DJ, Overstreet DH, Breese GR. Baclofen blocks expression and sensitization of anxiety-like behavior in an animal model of repeated stress and ethanol withdrawal. Alcohol Clin Exp Res 2007; 31:582-95. [PMID: 17374037 PMCID: PMC2864137 DOI: 10.1111/j.1530-0277.2007.00342.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Repeated exposures to forced ethanol diets (EDs) or restraint stress sensitize anxiety-like behavior during a future ethanol withdrawal. The present investigation assessed whether pretreatment of rats with agents targeting receptor systems thought to be important in treating relapse in alcoholic patients would prevent sensitization of anxiety-like behavior. METHODS Groups of rats were exposed to either (1) three 5-day cycles of ED with 2 days of withdrawal between cycles, (2) continuous ED, or (3) 5 days of ED in a single cycle preceded by 2 episodes of restraint stress 6 days apart. Drugs [baclofen, acamprosate, naloxone, lamotrigine, ifenprodil, dizocilpine (MK-801), CGS19755, diazepam, flumazenil, or 6-methyl-2-(phenylethynyl)pyridine] were given prophylactically during the first and second withdrawal periods only or, in separate baclofen experiments, acutely during the third withdrawal or during withdrawal from continuous ED. Baclofen administration preceded each stress session in the stress-withdrawal protocols. Anxiety-like behavior was assessed in the social interaction (SI) test 5 hours after the ethanol was removed or after 3 days of abstinence. RESULTS Baclofen (1.25, 2.5, and 5 mg/kg), flumazenil (5 mg/kg), and diazepam (1 mg/kg) blocked the reduction in SI induced by ethanol withdrawal. Among the drugs that alter glutamate function, only acamprosate (300 mg/kg) was effective. In the stress protocols, baclofen (5 mg/kg) given before each of the 2 restraint stress sessions before ethanol exposure or before stress during abstinence also attenuated SI deficits. CONCLUSIONS These findings suggest that GABAB and GABAA, but not glutamate or opioid mechanisms, are involved in adaptive changes associated with anxiety-like behavior induced by these repeated ethanol-withdrawal and stress-withdrawal paradigms. The lack of action of agents attenuating different aspects of glutamate function suggests that acamprosate's action is related to some other, as yet undetermined, mechanism.
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Affiliation(s)
- Darin J Knapp
- Department of Psychiatry, Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7178, USA.
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Affiliation(s)
- David H Overstreet
- Center for Alcohol Studies, University of North Carolina, Chapel Hill, NC 27599-7178, USA.
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