1
|
Scheggi S, Concas L, Corsi S, Carta M, Melis M, Frau R. Expanding the therapeutic potential of neuro(active)steroids: a promising strategy for hyperdopaminergic behavioral phenotypes. Neurosci Biobehav Rev 2024; 164:105842. [PMID: 39103066 DOI: 10.1016/j.neubiorev.2024.105842] [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: 05/23/2024] [Revised: 07/10/2024] [Accepted: 08/01/2024] [Indexed: 08/07/2024]
Abstract
Imbalances in dopamine activity significantly contribute to the pathophysiology of several neuropsychiatric disorders, including addiction, ADHD, schizophrenia, impulse control disorders, and Parkinson's Disease. Neuro(active)steroids, comprising endogenous steroids that finely modulate neuronal activity, are considered crucial regulators of brain function and behavior, with implications in various physiological processes and pathological conditions. Specifically, subclasses of Neuro(active)steroids belonging to the 5α reductase pathway are prominently involved in brain disorders characterized by dopaminergic signaling imbalances. This review highlights the neuromodulatory effects of Neuro(active)steroids on the dopamine system and related aberrant behavioral phenotypes. We critically appraise the role of pregnenolone, progesterone, and allopregnanolone on dopamine signaling. Additionally, we discuss the impact of pharmacological interventions targeting 5α reductase activity in neuropsychiatric conditions characterized by excessive activation of the dopaminergic system, ranging from psychotic (endo)phenotypes and motor complications to decision-making problems and addiction.
Collapse
Affiliation(s)
- Simona Scheggi
- Dept. of Molecular and Developmental Medicine, University of Siena, Italy
| | - Luca Concas
- Dept. Of Biomedical Sciences, University of Cagliari, Italy
| | - Sara Corsi
- Dept. of Developmental and Regenerative Neurobiology, Lund University, Sweden
| | - Manolo Carta
- Dept. Of Biomedical Sciences, University of Cagliari, Italy
| | - Miriam Melis
- Dept. Of Biomedical Sciences, University of Cagliari, Italy
| | - Roberto Frau
- Dept. Of Biomedical Sciences, University of Cagliari, Italy; Guy Everett Laboratory, University of Cagliari, Cagliari, Italy.
| |
Collapse
|
2
|
Peart DR, Claridge EV, Karlovcec JM, El Azali R, LaDouceur KE, Sikic A, Thomas A, Stone AP, Murray JE. Generalization of a positive-feature interoceptive morphine occasion setter across the rat estrous cycle. Horm Behav 2024; 162:105541. [PMID: 38583235 DOI: 10.1016/j.yhbeh.2024.105541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 03/17/2024] [Accepted: 03/29/2024] [Indexed: 04/09/2024]
Abstract
INTRODUCTION Interoceptive stimuli elicited by drug administration acquire conditioned modulatory properties of the induction of conditioned appetitive behaviours by exteroceptive cues. This effect may be modeled using a drug discrimination task in which the drug stimulus is trained as a positive-feature (FP) occasion setter (OS) that disambiguates the relation between an exteroceptive light conditioned stimulus (CS) and a sucrose unconditioned stimulus (US). We previously reported that females are less sensitive to generalization of a FP morphine OS than males, so we investigated the role of endogenous ovarian hormones in this difference. METHODS Male and female rats received intermixed injections of 3.2 mg/kg morphine or saline before each daily training session. Training consisted of 8 presentations of the CS, each followed by access to sucrose on morphine, but not saline sessions. Following acquisiton, rats were tested for generalization of the morphine stimulus to 0, 1.0, 3.2, and 5.4 mg/kg morphine. Female rats were monitored for estrous cyclicity using vaginal cytology throughout the study. RESULTS Both sexes acquired stable drug discrimination. A gradient of generalization was measured across morphine doses and this behaviour did not differ by sex, nor did it differ across the estrous cycle in females. CONCLUSIONS Morphine generalization is independent of fluctuations in levels of sex and endogenous gonadal hormones in females under these experimental conditions.
Collapse
Affiliation(s)
- Davin R Peart
- Department of Psychology, University of Guelph, Guelph, ON, Canada; Collaborative Neurosciences Graduate Program, University of Guelph, Guelph, ON, Canada
| | - Ella V Claridge
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Jessica M Karlovcec
- Department of Psychology, University of Guelph, Guelph, ON, Canada; Collaborative Neurosciences Graduate Program, University of Guelph, Guelph, ON, Canada
| | - Rita El Azali
- Department of Psychology, University of Guelph, Guelph, ON, Canada; Collaborative Neurosciences Graduate Program, University of Guelph, Guelph, ON, Canada
| | - Kathleen E LaDouceur
- Department of Psychology, University of Guelph, Guelph, ON, Canada; Collaborative Neurosciences Graduate Program, University of Guelph, Guelph, ON, Canada
| | - Anita Sikic
- Department of Psychology, University of Guelph, Guelph, ON, Canada; Collaborative Neurosciences Graduate Program, University of Guelph, Guelph, ON, Canada
| | - Abina Thomas
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Adiia P Stone
- Department of Psychology, University of Guelph, Guelph, ON, Canada; Collaborative Neurosciences Graduate Program, University of Guelph, Guelph, ON, Canada
| | - Jennifer E Murray
- Department of Psychology, University of Guelph, Guelph, ON, Canada; Collaborative Neurosciences Graduate Program, University of Guelph, Guelph, ON, Canada.
| |
Collapse
|
3
|
Bortolato M, Coffey BJ, Gabbay V, Scheggi S. Allopregnanolone: The missing link to explain the effects of stress on tic exacerbation? J Neuroendocrinol 2022; 34:e13022. [PMID: 34423500 PMCID: PMC8800948 DOI: 10.1111/jne.13022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/19/2021] [Accepted: 07/26/2021] [Indexed: 12/13/2022]
Abstract
The neurosteroid allopregnanolone (3α-hydroxy-5α-pregnan-20-one; AP) elicits pleiotropic effects in the central nervous system, ranging from neuroprotective and anti-inflammatory functions to the regulation of mood and emotional responses. Several lines of research show that the brain rapidly produces AP in response to acute stress to reduce the allostatic load and enhance coping. These effects not only are likely mediated by GABAA receptor activation but also result from the contributions of other mechanisms, such as the stimulation of membrane progesterone receptors. In keeping with this evidence, AP has been shown to exert rapid, potent antidepressant properties and has been recently approved for the therapy of moderate-to-severe postpartum depression. In addition to depression, emerging evidence points to the potential of AP as a therapy for other neuropsychiatric disorders, including anxiety, seizures, post-traumatic stress disorder and cognitive problems. Although this evidence has spurred interest in further therapeutic applications of AP, some investigations suggest that this neurosteroid may also be associated with adverse events in specific disorders. For example, our group has recently documented that AP increases tic-like manifestations in several animal models of tic disorders; furthermore, our results indicate that inhibiting AP synthesis and signalling reduces the exacerbation of tic severity associated with acute stress. Although the specific mechanisms of these effects remain partially elusive, our findings point to the possibility that the GABAergic activation by AP may also lead to disinhibitory effects, which could interfere with the ability of patients to suppress their tics. Future studies will be necessary to verify whether these mechanisms may apply to other externalising manifestations, such as impulse-control problems and manic symptoms.
Collapse
Affiliation(s)
- Marco Bortolato
- Department of Pharmacology and ToxicologyCollege of PharmacyUniversity of UtahSalt Lake CityUTUSA
- Research Consortium on NeuroEndocrine Causes of Tics (ReConNECT)
| | - Barbara J. Coffey
- Research Consortium on NeuroEndocrine Causes of Tics (ReConNECT)
- Department of Psychiatry and Behavioral ScienceMiller School of MedicineUniversity of MiamiMiamiFLUSA
| | - Vilma Gabbay
- Research Consortium on NeuroEndocrine Causes of Tics (ReConNECT)
- Department of Psychiatry and Behavioral SciencesAlbert Einstein College of MedicineBronxNYUSA
| | - Simona Scheggi
- Department of Molecular and Developmental MedicineSchool of MedicineUniversity of SienaSienaItaly
| |
Collapse
|
4
|
Abstract
Sexually dimorphic effects of alcohol exposure throughout life have been documented in clinical and preclinical studies. In the past, rates of alcohol use disorder (AUD) were higher in men than in women, but over the past 10 years, the difference between sexes in prevalence of AUD and binge drinking has narrowed. Recent evidence adds to historical data regarding the influence of sex steroids on alcohol drinking and the interaction with stress-related steroids. This review considers the contribution of the endocrine system to alcohol drinking in females, with a focus on the hypothalamic pituitary gonadal axis and the hypothalamic pituitary adrenal axis and their reciprocal interactions. Emphasis is given to preclinical studies that examined genomic and rapid membrane effects of estrogen, progesterone, glucocorticoids, and GABAergic neurosteroids for their effects on alcohol drinking and models of relapse. Pertinent comparisons to data in males highlight divergent effects of sex and stress steroids on alcohol drinking and emphasize the importance of considering sex in the development of novel pharmacotherapeutic targets for the treatment of AUD. For instance, pharmacological strategies targeting the corticotropin releasing factor and glucocorticoid receptor systems may be differentially effective in males and females, whereas strategies to enhance GABAergic neurosteroids may represent a biomarker of treatment efficacy in both sexes.
Collapse
Affiliation(s)
- Deborah A Finn
- Oregon Health & Science University, Portland, Oregon.,Veterans Affairs Portland Health Care System, Portland, Oregon
| |
Collapse
|
5
|
Tomaselli G, Vallée M. Stress and drug abuse-related disorders: The promising therapeutic value of neurosteroids focus on pregnenolone-progesterone-allopregnanolone pathway. Front Neuroendocrinol 2019; 55:100789. [PMID: 31525393 DOI: 10.1016/j.yfrne.2019.100789] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 08/14/2019] [Accepted: 09/09/2019] [Indexed: 02/06/2023]
Abstract
The pregnenolone-progesterone-allopregnanolone pathway is receiving increasing attention in research on the role of neurosteroids in pathophysiology, particularly in stress-related and drug use disorders. These disorders involve an allostatic change that may result from deficiencies in allostasis or adaptive responses, and may be downregulated by adjustments in neurotransmission by neurosteroids. The following is an overview of findings that assess how pregnenolone and/or allopregnanolone concentrations are altered in animal models of stress and after consumption of alcohol or cannabis-type drugs, as well as in patients with depression, anxiety, post-traumatic stress disorder or psychosis and/or in those diagnosed with alcohol or cannabis use disorders. Preclinical and clinical evidence shows that pregnenolone and allopregnanolone, operating according to a different or common pharmacological profile involving GABAergic and/or endocannabinoid system, may be relevant biomarkers of psychiatric disorders for therapeutic purposes. Hence, ongoing clinical trials implicate synthetic analogs of pregnenolone or allopregnanolone, and also modulators of neurosteroidogenesis.
Collapse
Affiliation(s)
- Giovanni Tomaselli
- INSERM U1215, Neurocentre Magendie, Group "Physiopathology and Therapeutic Approaches of Stress-Related Disease", 146 Rue Léo Saignat, 33000 Bordeaux, France; University of Bordeaux, 33000 Bordeaux, France
| | - Monique Vallée
- INSERM U1215, Neurocentre Magendie, Group "Physiopathology and Therapeutic Approaches of Stress-Related Disease", 146 Rue Léo Saignat, 33000 Bordeaux, France; University of Bordeaux, 33000 Bordeaux, France.
| |
Collapse
|
6
|
Abstract
The term neurosteroid refers to rapid membrane actions of steroid hormones and their derivatives that can modulate physiological functions and behavior via their interactions with ligand-gated ion channels. This chapter will highlight recent advances pertaining to the modulatory effects of a select group of neurosteroids that are primarily potent positive allosteric modulators of γ-aminobutyric acidA receptors (GABAARs). Nanomolar concentrations of neurosteroids, which occur in vivo, potentiate phasic and tonic forms of GABAAR-mediated inhibition, indicating that both synaptic and extrasynaptic GABAARs possess sensitivity to neurosteroids and contribute to the overall ability of neurosteroids to modulate central nervous system excitability. Common effects of alcohol and neurosteroids at GABAARs have stimulated research on the ability of neurosteroids to modulate alcohol's acute and chronic effects. Background on neurosteroid pharmacology and biosynthetic enzymes will be provided as it relates to experimental findings. Data will be summarized on alcohol and neurosteroid interactions across neuroanatomical regions and models of intoxication, consumption, dependence, and withdrawal. Evidence supports independent regulation of neurosteroid synthesis between periphery and brain as well as across brain regions following acute alcohol administration and during withdrawal. Local mechanisms for fine-tuning neuronal excitability via manipulation of neurosteroid synthesis exert predicted behavioral and electrophysiological responses on GABAAR-mediated inhibition. Collectively, targeting neurosteroidogenesis may be a beneficial treatment strategy for alcohol use disorders.
Collapse
|
7
|
Spencer S, Neuhofer D, Chioma VC, Garcia-Keller C, Schwartz DJ, Allen N, Scofield MD, Ortiz-Ithier T, Kalivas PW. A Model of Δ 9-Tetrahydrocannabinol Self-administration and Reinstatement That Alters Synaptic Plasticity in Nucleus Accumbens. Biol Psychiatry 2018; 84:601-610. [PMID: 29861097 PMCID: PMC6162175 DOI: 10.1016/j.biopsych.2018.04.016] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 04/17/2018] [Accepted: 04/26/2018] [Indexed: 01/12/2023]
Abstract
BACKGROUND Cannabis is the most widely used illicit drug, but knowledge of the neurological consequences of cannabis use is deficient. Two primary components of cannabis are Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD). We established a THC+CBD model of self-administration and reinstated drug seeking to determine if, similar to other addictive drugs, cannabis produces enduring synaptic changes in nucleus accumbens core (NAcore) thought to contribute vulnerability to drug reinstatement. METHODS Sprague Dawley rats were trained to self-administer THC+CBD (n = 165) or were used as vehicle self-administering control animals (n = 24). Reinstatement was initiated by context, cues, drug priming, and stress (yohimbine injection). Enduring neuroadaptations produced by THC+CBD self-administration were assayed using four measures: dendritic spine morphology, long-term depression, alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid/N-methyl-D-aspartate ratios, and behavioral pharmacology. RESULTS We described a novel rodent model of cannabis relapse involving intravenous THC+CBD self-administration and drug seeking induced by conditioned context, cues, and stress. Cued reinstatement of THC+CBD seeking depended on a sequence of events implicated in relapse to other addictive drugs, as reinstatement was prevented by daily treatment with N-acetylcysteine or acute intra-NAcore pretreatment with a neuronal nitric oxide synthase or matrix metalloprotease-9 inhibitor, all of which normalize impaired glutamate homeostasis. The capacity to induce N-methyl-D-aspartate long-term depression in NAcore medium spiny neurons was abolished and dendritic spine density was reduced, but alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid/N-methyl-D-aspartate ratio was unaltered in THC+CBD-trained animals, akin to opioids, but not to psychostimulants. CONCLUSIONS We report enduring consequences of THC+CBD use on critical relapse circuitry and synaptic physiology in NAcore following rat self-administration and provide the first report of cue- and stress-induced reinstatement with this model.
Collapse
Affiliation(s)
- Sade Spencer
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina.
| | - Daniela Neuhofer
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina
| | - Vivian C Chioma
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina
| | - Constanza Garcia-Keller
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina
| | - Danielle J Schwartz
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina
| | - Nicholas Allen
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina
| | - Michael D Scofield
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina; Department of Anesthesiology, Medical University of South Carolina, Charleston, South Carolina
| | - Tara Ortiz-Ithier
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina; Department of Physiology, University of Puerto Rico, Rio Piedras, Puerto Rico
| | - Peter W Kalivas
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina
| |
Collapse
|
8
|
Blegen MB, da Silva E Silva D, Bock R, Morisot N, Ron D, Alvarez VA. Alcohol operant self-administration: Investigating how alcohol-seeking behaviors predict drinking in mice using two operant approaches. Alcohol 2018; 67:23-36. [PMID: 29310048 PMCID: PMC5939586 DOI: 10.1016/j.alcohol.2017.08.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 07/27/2017] [Accepted: 08/10/2017] [Indexed: 02/07/2023]
Abstract
Alcohol operant self-administration paradigms are critical tools for studying the neural circuits implicated in both alcohol-seeking and consummatory behaviors and for understanding the neural basis underlying alcohol-use disorders. In this study, we investigate the predictive value of two operant models of oral alcohol self-administration in mice, one in which alcohol is delivered into a cup following nose-poke responses with no accurate measurement of consumed alcohol solution, and another paradigm that provides access to alcohol via a sipper tube following lever presses and where lick rate and consumed alcohol volume can be measured. The goal was to identify a paradigm where operant behaviors such as lever presses and nose pokes, as well as other tracked behavior such as licks and head entries, can be used to reliably predict blood alcohol concentration (BAC). All mice were first exposed to alcohol in the home cage using the "drinking in the dark" (DID) procedure for 3 weeks and then were trained in alcohol self-administration using either of the operant paradigms for several weeks. Even without sucrose fading or food pre-training, mice acquired alcohol self-administration with both paradigms. However, neither lever press nor nose-poke rates were good predictors of alcohol intake or BAC. Only the lick rate and consumed alcohol were consistently and significantly correlated with BAC. Using this paradigm that accurately measures alcohol intake, unsupervised cluster analysis revealed three groups of mice: high-drinking (43%), low-drinking (37%), and non-drinking mice (20%). High-drinking mice showed faster acquisition of operant responding and achieved higher BACs than low-drinking mice. Lick rate and volume consumed varied with the alcohol concentration made available only for high- and low-drinking mice, but not for non-drinking mice. In addition, high- and low-drinking mice showed similar patterns during extinction and significant cue-induced reinstatement of seeking. Only high-drinking mice showed insensitivity to quinine adulteration, indicating a willingness to drink alcohol despite pairing with aversive stimuli. Thus, this study shows that relying on active presses is not an accurate determination of drinking behavior in mice. Only paradigms that allow for accurate measurements of consumed alcohol and/or lick rate are valid models of operant alcohol self-administration, where compulsive-like drinking could be accurately determined based on changes in alcohol intake when paired with bitter-tasting stimuli.
Collapse
Affiliation(s)
- Mariah B Blegen
- Laboratory on Neurobiology of Compulsive Behaviors, National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892, USA
| | - Daniel da Silva E Silva
- Laboratory on Neurobiology of Compulsive Behaviors, National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892, USA; Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil; CAPES Foundation, Ministry of Education of Brazil, Brasília, DF, 70.040-020, Brazil
| | - Roland Bock
- Laboratory on Neurobiology of Compulsive Behaviors, National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892, USA
| | - Nadege Morisot
- Department of Neurology, University of California San Francisco, San Francisco, CA 94143-0663, USA
| | - Dorit Ron
- Department of Neurology, University of California San Francisco, San Francisco, CA 94143-0663, USA
| | - Veronica A Alvarez
- Laboratory on Neurobiology of Compulsive Behaviors, National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892, USA.
| |
Collapse
|
9
|
Chandler CM, Overton JS, Rüedi-Bettschen D, Platt DM. GABA A Receptor Subtype Mechanisms and the Abuse-Related Effects of Ethanol: Genetic and Pharmacological Evidence. Handb Exp Pharmacol 2018; 248:3-27. [PMID: 29204713 DOI: 10.1007/164_2017_80] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Ethanol's reinforcing and subjective effects, as well as its ability to induce relapse, are powerful factors contributing to its widespread use and abuse. A significant mediator of these behavioral effects is the GABAA receptor system. GABAA receptors are the target for γ-aminobutyric acid (GABA), the major inhibitory neurotransmitter in the CNS. Structurally, they are pentameric, transmembrane chloride ion channels comprised of subunits from at least eight different families of distinct proteins. The contribution of different GABAA subunits to ethanol's diverse abuse-related effects is not clear and remains an area of research focus. This chapter details the clinical and preclinical findings supporting roles for different α, β, γ, and δ subunit-containing GABAA receptors in ethanol's reinforcing, subjective/discriminative stimulus, and relapse-inducing effects. The reinforcing properties of ethanol have been studied the most systematically, and convergent preclinical evidence suggests a key role for the α5 subunit in those effects. Regarding ethanol's subjective/discriminative stimulus effects, clinical and genetic findings support a primary role for the α2 subunit, whereas preclinical evidence implicates the α5 subunit. At present, too few studies investigating ethanol relapse exist to make any solid conclusions regarding the role of specific GABAA subunits in this abuse-related effect.
Collapse
Affiliation(s)
- Cassie M Chandler
- Graduate Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS, USA
| | - John S Overton
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, USA
| | - Daniela Rüedi-Bettschen
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, USA
| | - Donna M Platt
- Graduate Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS, USA.
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, USA.
| |
Collapse
|
10
|
Porcu P, Barron AM, Frye CA, Walf AA, Yang SY, He XY, Morrow AL, Panzica GC, Melcangi RC. Neurosteroidogenesis Today: Novel Targets for Neuroactive Steroid Synthesis and Action and Their Relevance for Translational Research. J Neuroendocrinol 2016; 28:12351. [PMID: 26681259 PMCID: PMC4769676 DOI: 10.1111/jne.12351] [Citation(s) in RCA: 123] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Revised: 12/12/2015] [Accepted: 12/12/2015] [Indexed: 12/19/2022]
Abstract
Neuroactive steroids are endogenous neuromodulators synthesised in the brain that rapidly alter neuronal excitability by binding to membrane receptors, in addition to the regulation of gene expression via intracellular steroid receptors. Neuroactive steroids induce potent anxiolytic, antidepressant, anticonvulsant, sedative, analgesic and amnesic effects, mainly through interaction with the GABAA receptor. They also exert neuroprotective, neurotrophic and antiapoptotic effects in several animal models of neurodegenerative diseases. Neuroactive steroids regulate many physiological functions, such as the stress response, puberty, the ovarian cycle, pregnancy and reward. Their levels are altered in several neuropsychiatric and neurological diseases and both preclinical and clinical studies emphasise a therapeutic potential of neuroactive steroids for these diseases, whereby symptomatology ameliorates upon restoration of neuroactive steroid concentrations. However, direct administration of neuroactive steroids has several challenges, including pharmacokinetics, low bioavailability, addiction potential, safety and tolerability, which limit its therapeutic use. Therefore, modulation of neurosteroidogenesis to restore the altered endogenous neuroactive steroid tone may represent a better therapeutic approach. This review summarises recent approaches that target the neuroactive steroid biosynthetic pathway at different levels aiming to promote neurosteroidogenesis. These include modulation of neurosteroidogenesis through ligands of the translocator protein 18 kDa and the pregnane xenobiotic receptor, as well as targeting of specific neurosteroidogenic enzymes such as 17β-hydroxysteroid dehydrogenase type 10 or P450 side chain cleavage. Enhanced neurosteroidogenesis through these targets may be beneficial not only for neurodegenerative diseases, such as Alzheimer's disease and age-related dementia, but also for neuropsychiatric diseases, including alcohol use disorders.
Collapse
Affiliation(s)
- Patrizia Porcu
- Neuroscience Institute, National Research Council of Italy (CNR), Cagliari, Italy
| | - Anna M. Barron
- Molecular Imaging Center, National Institute of Radiological Sciences, Anagawa, Inage-ku, Chiba, Japan
| | - Cheryl Anne Frye
- Institute of Arctic Biology, The University of Alaska–Fairbanks, Fairbanks, AK, USA
- The University at Albany, Albany, NY, USA
| | - Alicia A. Walf
- Institute of Arctic Biology, The University of Alaska–Fairbanks, Fairbanks, AK, USA
- The University at Albany, Albany, NY, USA
- Department of Cognitive Science, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Song-Yu Yang
- Department of Developmental Biochemistry, NYS Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - Xue-Ying He
- Department of Developmental Biochemistry, NYS Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - A. Leslie Morrow
- Departments of Psychiatry and Pharmacology, Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Gian Carlo Panzica
- Department of Neuroscience, University of Turin, and NICO - Neuroscience Institute Cavalieri Ottolenghi, Orbassano, Italy
| | - Roberto C. Melcangi
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| |
Collapse
|
11
|
Ford MM, Nickel JD, Kaufman MN, Finn DA. Null mutation of 5α-reductase type I gene alters ethanol consumption patterns in a sex-dependent manner. Behav Genet 2015; 45:341-53. [PMID: 25416204 PMCID: PMC4425631 DOI: 10.1007/s10519-014-9694-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 11/10/2014] [Indexed: 02/04/2023]
Abstract
The neuroactive steroid allopregnanolone (ALLO) is a positive modulator of GABAA receptors, and manipulation of neuroactive steroid levels via injection of ALLO or the 5α-reductase inhibitor finasteride alters ethanol self-administration patterns in male, but not female, mice. The Srd5a1 gene encodes the enzyme 5α-reductase-1, which is required for the synthesis of ALLO. The current studies investigated the influence of Srd5a1 deletion on voluntary ethanol consumption in male and female wildtype (WT) and knockout (KO) mice. Under a continuous access condition, 6 and 10 % ethanol intake was significantly greater in KO versus WT females, but significantly lower in KO versus WT males. In 2-h limited access sessions, Srd5a1 deletion retarded acquisition of 10 % ethanol intake in female mice, but facilitated it in males, versus respective WT mice. The present findings demonstrate that the Srd5a1 gene modulates ethanol consumption in a sex-dependent manner that is also contingent upon ethanol access condition and concentration.
Collapse
Affiliation(s)
- Matthew M Ford
- Department of Behavioral Neuroscience, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR, 97239, USA,
| | | | | | | |
Collapse
|
12
|
Ramaker MJ, Strong-Kaufman MN, Ford MM, Phillips TJ, Finn DA. Effect of nucleus accumbens shell infusions of ganaxolone or gaboxadol on ethanol consumption in mice. Psychopharmacology (Berl) 2015; 232:1415-26. [PMID: 25342197 PMCID: PMC4412309 DOI: 10.1007/s00213-014-3777-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 10/10/2014] [Indexed: 01/16/2023]
Abstract
RATIONALE Allopregnanolone (ALLO) is an endogenous neuroactive steroid thought to alter the reinforcement value of alcohol (ethanol) due to its actions as a positive modulator of the GABAA receptor (GABAAR). Extrasynaptic GABAARs may be a particularly sensitive target of ethanol and neuroactive steroids. Previous work showed that systemic injections of an ALLO analog, ganaxolone (GAN), or an extrasynaptic GABAAR agonist (gaboxadol; THIP) decreased ethanol intake in male mice with limited access to ethanol. OBJECTIVES The present studies tested whether activation of GABAARs in the nucleus accumbens (NAc) shell by GAN or THIP was sufficient to reduce ethanol intake. C57BL/6J male mice had 2-h access to 10 % ethanol (10E) and water, and 10E intake was measured following site-specific infusions of GAN or THIP. RESULTS Decreases in limited-access 10E consumption were observed following site-specific bilateral infusions of either drug into the NAc shell. Significant changes in intake were absent when the drugs were infused in a region dorsal to the target site (GAN) or into the lateral ventricle (THIP). Locomotor data confirmed that the decreases in intake were not due to a sedative effect of the drugs. CONCLUSIONS These data demonstrate the sufficiency of GABAAR activation by a positive allosteric modulator or an agonist with selectivity for extrasynaptic GABAARs to decrease ethanol consumption in mice. Importantly, more refined GABAAR-active targets that decrease ethanol intake may enhance our understanding and ability to treat alcohol use disorders.
Collapse
Affiliation(s)
- Marcia J. Ramaker
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239
| | | | - Matthew M. Ford
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239
| | - Tamara J. Phillips
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239,Department of Veterans Affairs Medical Research, Portland, OR 97239
| | - Deborah A. Finn
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239,Department of Veterans Affairs Medical Research, Portland, OR 97239
| |
Collapse
|
13
|
Weiland A, Garcia S, Knackstedt LA. Ceftriaxone and cefazolin attenuate the cue-primed reinstatement of alcohol-seeking. Front Pharmacol 2015; 6:44. [PMID: 25805996 PMCID: PMC4354333 DOI: 10.3389/fphar.2015.00044] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 02/19/2015] [Indexed: 11/13/2022] Open
Abstract
Alcohol consumption and the reinstatement of alcohol-seeking rely on glutamate and GABA transmission. Modulating these neurotransmitters may be a viable treatment strategy to prevent alcohol relapse. N-acetylcysteine (NAC) and the antibiotic ceftriaxone (CEF) alter the glial reuptake and release of glutamate while the antibiotic cefazolin (CEFAZ) modulates GABA signaling without affecting glutamate. Here, we used the extinction-reinstatement model of relapse to test the ability of these compounds to attenuate the reinstatement of alcohol-seeking. Male Sprague-Dawley rats were trained to self-administer 20% (v/v) alcohol in the home cage using an intermittent schedule (24 h on, 24 h off) for 12 sessions. Subsequently, animals self-administered alcohol during daily 45-min operant sessions for 26 sessions, followed by extinction training. We tested whether chronic administration of NAC, CEF, or CEFAZ attenuated the cue-primed reinstatement of alcohol-seeking. CEF and CEFAZ attenuated cue-primed reinstatement of alcohol-seeking while NAC had no effect. We subsequently investigated whether CEF and CEFAZ alter the self-administration of sucrose and chow pellets and if CEFAZ attenuates the reinstatement of cocaine-seeking. The operant self-administration of regular chow and sucrose was not altered by either CEF or CEFAZ. CEFAZ had no effect on cocaine reinstatement, a behavior that has been strongly tied to altered glutamate homeostasis in the nucleus accumbens. Thus the ability of CEFAZ to attenuate alcohol reinstatement likely does not involve the glial modulation of glutamate levels. The dampening of GABA transmission may be a common mechanism of action of cefazolin and ceftriaxone.
Collapse
Affiliation(s)
- Ana Weiland
- Department of Neuroscience, Medical University of South Carolina Charleston, SC, USA
| | - Steven Garcia
- Department of Neuroscience, Medical University of South Carolina Charleston, SC, USA
| | - Lori A Knackstedt
- Department of Neuroscience, Medical University of South Carolina Charleston, SC, USA
| |
Collapse
|
14
|
Effects of the neuroactive steroid allopregnanolone on intracranial self-stimulation in C57BL/6J mice. Psychopharmacology (Berl) 2014; 231:3415-3423. [PMID: 24810108 PMCID: PMC4692244 DOI: 10.1007/s00213-014-3600-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 04/20/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE The neuroactive steroid (3α,5α)-3-hydroxy-pregnan-20-one (3α,5α-THP, allopregnanolone) has effects on reward-related behaviors in mice and rats that suggest that it may activate brain reward circuits. Intracranial self-stimulation (ICSS) is an operant behavioral technique that detects changes in the sensitivity of brain reward circuitry following drug administration. OBJECTIVE To examine the effects of the neuroactive steroid allopregnanolone on ICSS and to compare these effects to those of cocaine. METHODS Male C57BL/6J mice implanted with stimulating electrodes implanted into the medial forebrain bundle responded for reinforcement by electrical stimulation (brain stimulation reward (BSR)). Mice received cocaine (n = 11, 3.0-30.0 mg/kg, intraperitoneal (i.p.)) or the neuroactive steroid allopregnanolone (n = 11, 3.0-17.0 mg/kg, i.p.). BSR thresholds (θ 0) and maximum (MAX) operant response rates after drug treatments were compared to those after vehicle injections. RESULTS Cocaine and allopregnanolone dose dependently lowered BSR thresholds relative to vehicle injections. Cocaine was maximally effective (80 % reduction) in the second 15 min following the 30 mg/kg dose, while allopregnanolone was maximally effective (30 % reduction) 15-45 min after the 17 mg/kg dose. Neither drug had significant effects on MAX response rates. CONCLUSIONS The effects of allopregnanolone on BSR thresholds are consistent with the previously reported effects of benzodiazepines and alcohol, suggesting that positive modulation of GABAA receptors can facilitate reward-related behaviors in C57BL/6J mice.
Collapse
|
15
|
Porcu P, Morrow AL. Divergent neuroactive steroid responses to stress and ethanol in rat and mouse strains: relevance for human studies. Psychopharmacology (Berl) 2014; 231:3257-72. [PMID: 24770626 PMCID: PMC4135033 DOI: 10.1007/s00213-014-3564-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 03/25/2014] [Indexed: 01/09/2023]
Abstract
RATIONALE Neuroactive steroids are endogenous or synthetic steroids that rapidly alter neuronal excitability via membrane receptors, primarily γ-aminobutyric acid type A (GABAA) receptors. Neuroactive steroids regulate many physiological processes including hypothalamic-pituitary-adrenal (HPA) axis function, ovarian cycle, pregnancy, aging, and reward. Moreover, alterations in neuroactive steroid synthesis are implicated in several neuropsychiatric disorders. OBJECTIVES This review will summarize the pharmacological properties and physiological regulation of neuroactive steroids, with a particular focus on divergent neuroactive steroid responses to stress and ethanol in rats, mice, and humans. RESULTS GABAergic neuroactive steroids exert a homeostatic regulation of the HPA axis in rats and humans, whereby the increase in neuroactive steroid levels following acute stress counteracts HPA axis hyperactivity and restores homeostasis. In contrast, in C57BL/6J mice, acute stress decreases neurosteroidogenesis and neuroactive steroids exert paradoxical excitatory effects upon the HPA axis. Rats, mice, and humans also differ in the neuroactive steroid responses to ethanol. Genetic variation in neurosteroidogenesis may explain the different neuroactive steroid responses to stress or ethanol. CONCLUSIONS Rats and mouse strains show divergent effects of stress and ethanol on neuroactive steroids in both plasma and brain. The study of genetic variation in the various processes that determine neuroactive steroids levels as well as their effects on cell signaling may underlie these differences and may play a relevant role for the potential therapeutic benefits of neuroactive steroids.
Collapse
Affiliation(s)
- Patrizia Porcu
- Neuroscience Institute, National Research Council of Italy (CNR), Cittadella Universitaria, 09042, Monserrato, Cagliari, Italy,
| | | |
Collapse
|
16
|
Ramaker MJ, Ford MM, Phillips TJ, Finn DA. Differences in the reinstatement of ethanol seeking with ganaxolone and gaboxadol. Neuroscience 2014; 272:180-7. [PMID: 24814021 DOI: 10.1016/j.neuroscience.2014.04.065] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 04/21/2014] [Accepted: 04/24/2014] [Indexed: 10/25/2022]
Abstract
The endogenous neuroactive steroid allopregnanolone (ALLO) has previously been shown to induce reinstatement of ethanol seeking in rodents. ALLO is a positive allosteric modulator at both synaptic and extrasynaptic GABAA receptors. The contribution of each class of GABAA receptors in mediating reinstatement of ethanol seeking is unknown. The first aim of the present study was to determine whether ganaxolone (GAN), a longer-acting synthetic analog of ALLO, also promotes reinstatement of ethanol seeking. The second aim was to examine whether preferentially activating extrasynaptic GABAA receptors with the selective agonist gaboxadol (THIP) was sufficient to reinstate responding for ethanol in mice. Male C57BL/6J mice were trained to lever press for access to a 10% ethanol (v/v) solution (10E), using a sucrose-fading procedure. Following extinction of the lever-pressing behavior, systemic THIP (0, 4 and 6mg/kg) and GAN (0, 10, and 15mg/kg) were tested for their ability to reinstate ethanol-appropriate responding in the absence of 10E access. GAN significantly increased lever pressing on the previously active lever, while THIP did not alter lever-pressing behavior. The results of this study suggest that direct activation of extrasynaptic GABAA receptors at the GABA site is not sufficient to induce ethanol seeking in the reinstatement procedure. Future studies are necessary to elucidate the mechanisms and brain areas by which differences in the pharmacological activity of GAN and THIP at the GABAA receptor contribute to the dissimilarity in their effect on the reinstatement of ethanol seeking. Nonetheless, based on the increased use of these drugs in clinical trials across multiple disease states, the effects of GAN or THIP on alcohol seeking may be an important consideration if these drugs are to be used clinically in a population with a co-occurring alcohol use disorder.
Collapse
Affiliation(s)
- M J Ramaker
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States.
| | - M M Ford
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States
| | - T J Phillips
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States; Department of Veterans Affairs Medical Research, Portland, OR 97239, United States
| | - D A Finn
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States; Department of Veterans Affairs Medical Research, Portland, OR 97239, United States
| |
Collapse
|
17
|
Lopez MF, Becker HC. Operant ethanol self-administration in ethanol dependent mice. Alcohol 2014; 48:295-9. [PMID: 24721194 DOI: 10.1016/j.alcohol.2014.02.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 02/17/2014] [Accepted: 02/19/2014] [Indexed: 12/28/2022]
Abstract
While rats have been predominantly used to study operant ethanol self-administration behavior in the context of dependence, several studies have employed operant conditioning procedures to examine changes in ethanol self-administration behavior as a function of chronic ethanol exposure and withdrawal experience in mice. This review highlights some of the advantages of using operant conditioning procedures for examining the motivational effects of ethanol in animals with a history of dependence. As reported in rats, studies using various operant conditioning procedures in mice have demonstrated significant escalation of ethanol self-administration behavior in mice rendered dependent via forced chronic ethanol exposure in comparison to nondependent mice. This paper also presents a summary of these findings, as well as suggestions for future studies.
Collapse
|
18
|
Porcu P, Locci A, Santoru F, Berretti R, Morrow AL, Concas A. Failure of acute ethanol administration to alter cerebrocortical and hippocampal allopregnanolone levels in C57BL/6J and DBA/2J mice. Alcohol Clin Exp Res 2014; 38:948-58. [PMID: 24428156 DOI: 10.1111/acer.12329] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 10/25/2013] [Indexed: 11/28/2022]
Abstract
BACKGROUND Ethanol (EtOH) administration increases brain allopregnanolone levels in rats, and this increase contributes to sensitivity to EtOH's behavioral effects. However, EtOH's effects on allopregnanolone may differ across species. We investigated the effects of acute EtOH administration on allopregnanolone, progesterone, and corticosterone levels in cerebral cortex and hippocampus of C57BL/6J and DBA/2J mice, 2 inbred strains with different alcohol sensitivity. METHODS Naïve male C57BL/6J and DBA/2J mice received EtOH (1, 2, 3, or 4 g/kg, intraperitoneally [i.p.]) or saline and were euthanized 1 hour later. For the time-course study, mice received EtOH (2 g/kg, i.p.) and were euthanized 15, 30, 60, and 120 minutes later. Steroids were measured by radioimmunoassay. RESULTS Acute EtOH administration did not alter cerebrocortical and hippocampal levels of allopregnanolone and progesterone in these strains at any of the doses and time points examined. Acute EtOH dose-dependently increased cerebrocortical corticosterone levels by 319, 347, and 459% in C57BL/6J mice at the doses of 2, 3, and 4 g/kg, and by 371, 507, 533, and 692% in DBA/2J mice at the doses of 1, 2, 3, and 4 g/kg, respectively. Similar changes were observed in the hippocampus. EtOH's effects on cerebrocortical corticosterone levels were also time dependent in both strains. Moreover, acute EtOH administration time-dependently increased plasma levels of progesterone and corticosterone. Finally, morphine administration increased cerebrocortical allopregnanolone levels in C57BL/6J (+77, +93, and +88% at 5, 10, and 30 mg/kg, respectively) and DBA/2J mice (+81% at 5 mg/kg), suggesting that the impairment in brain neurosteroidogenesis may be specific to EtOH. CONCLUSIONS These results underline important species differences on EtOH-induced brain neurosteroidogenesis. Acute EtOH increases brain and plasma corticosterone levels but does not alter cerebrocortical and hippocampal concentrations of allopregnanolone and progesterone in naïve C57BL/6J and DBA/2J mice.
Collapse
Affiliation(s)
- Patrizia Porcu
- Institute of Neuroscience, National Research Council of Italy (CNR), Cagliari, Italy
| | | | | | | | | | | |
Collapse
|
19
|
Schumacher M, Mattern C, Ghoumari A, Oudinet JP, Liere P, Labombarda F, Sitruk-Ware R, De Nicola AF, Guennoun R. Revisiting the roles of progesterone and allopregnanolone in the nervous system: resurgence of the progesterone receptors. Prog Neurobiol 2013; 113:6-39. [PMID: 24172649 DOI: 10.1016/j.pneurobio.2013.09.004] [Citation(s) in RCA: 245] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 09/15/2013] [Accepted: 09/21/2013] [Indexed: 02/08/2023]
Abstract
Progesterone is commonly considered as a female reproductive hormone and is well-known for its role in pregnancy. It is less well appreciated that progesterone and its metabolite allopregnanolone are also male hormones, as they are produced in both sexes by the adrenal glands. In addition, they are synthesized within the nervous system. Progesterone and allopregnanolone are associated with adaptation to stress, and increased production of progesterone within the brain may be part of the response of neural cells to injury. Progesterone receptors (PR) are widely distributed throughout the brain, but their study has been mainly limited to the hypothalamus and reproductive functions, and the extra-hypothalamic receptors have been neglected. This lack of information about brain functions of PR is unexpected, as the protective and trophic effects of progesterone are much investigated, and as the therapeutic potential of progesterone as a neuroprotective and promyelinating agent is currently being assessed in clinical trials. The little attention devoted to the brain functions of PR may relate to the widely accepted assumption that non-reproductive actions of progesterone may be mainly mediated by allopregnanolone, which does not bind to PR, but acts as a potent positive modulator of γ-aminobutyric acid type A (GABA(A) receptors. The aim of this review is to critically discuss effects of progesterone on the nervous system via PR, and of allopregnanolone via its modulation of GABA(A) receptors, with main focus on the brain.
Collapse
Affiliation(s)
- M Schumacher
- UMR 788 Inserm and University Paris-Sud, Kremlin-Bicêtre, France.
| | - C Mattern
- M et P Pharma AG, Emmetten, Switzerland
| | - A Ghoumari
- UMR 788 Inserm and University Paris-Sud, Kremlin-Bicêtre, France
| | - J P Oudinet
- UMR 788 Inserm and University Paris-Sud, Kremlin-Bicêtre, France
| | - P Liere
- UMR 788 Inserm and University Paris-Sud, Kremlin-Bicêtre, France
| | - F Labombarda
- Instituto de Biologia y Medicina Experimental and University of Buenos Aires, Argentina
| | - R Sitruk-Ware
- Population Council and Rockefeller University, New York, USA
| | - A F De Nicola
- Instituto de Biologia y Medicina Experimental and University of Buenos Aires, Argentina
| | - R Guennoun
- UMR 788 Inserm and University Paris-Sud, Kremlin-Bicêtre, France
| |
Collapse
|
20
|
Davies DL, Bortolato M, Finn DA, Ramaker MJ, Barak S, Ron D, Liang J, Olsen RW. Recent advances in the discovery and preclinical testing of novel compounds for the prevention and/or treatment of alcohol use disorders. Alcohol Clin Exp Res 2012; 37:8-15. [PMID: 22671690 DOI: 10.1111/j.1530-0277.2012.01846.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 03/26/2012] [Indexed: 11/27/2022]
Abstract
Alcohol abuse and dependence have a staggering socioeconomic impact, yet current therapeutic strategies are largely inadequate to treat these disorders. Thus, the development of new strategies that can effectively prevent alcohol use disorders (AUDs) is of paramount importance. Currently approved medications attempt to deter alcohol intake by blocking ethanol metabolism or by targeting the neurochemical systems downstream of the cascades leading to craving and dependence. Unfortunately, these medications have provided only limited success as indicated by the continued high rates of alcohol abuse and alcoholism. The lack of currently available effective treatment strategies is highlighted by the urgent call by the NIAAA to find new and paradigm-changing therapeutics to either prevent or treat alcohol-related problems. This mini-review highlights recent findings from 4 laboratories with a focus on compounds that have the potential to be novel therapeutic agents that can be developed for the prevention and/or treatment of AUDs.
Collapse
Affiliation(s)
- Daryl L Davies
- School of Pharmacy, University of Southern California, Los Angeles, CA 90033, USA.
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Yardley MM, Wyatt L, Khoja S, Asatryan L, Ramaker MJ, Finn DA, Alkana RL, Huynh N, Louie SG, Petasis NA, Bortolato M, Davies DL. Ivermectin reduces alcohol intake and preference in mice. Neuropharmacology 2012; 63:190-201. [PMID: 22465817 DOI: 10.1016/j.neuropharm.2012.03.014] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 03/13/2012] [Accepted: 03/14/2012] [Indexed: 12/19/2022]
Abstract
The high rate of therapeutic failure in the management of alcohol use disorders (AUDs) underscores the urgent need for novel and effective strategies that can deter ethanol consumption. Recent findings from our group showed that ivermectin (IVM), a broad-spectrum anthelmintic with high tolerability and optimal safety profile in humans and animals, antagonized ethanol-mediated inhibition of P2X4 receptors (P2X4Rs) expressed in Xenopus oocytes. This finding prompted us to hypothesize that IVM may reduce alcohol consumption; thus, in the present study we investigated the effects of this agent on several models of alcohol self-administration in male and female C57BL/6 mice. Overall, IVM (1.25-10 mg/kg, intraperitoneal) significantly reduced 24-h alcohol consumption and intermittent limited access (4-h) binge drinking, and operant alcohol self-administration (1-h). The effects on alcohol intake were dose-dependent with the significant reduction in intake at 9 h after administration corresponding to peak IVM concentrations (C(max)) in the brain. IVM also produced a significant reduction in 24-h saccharin consumption, but did not alter operant sucrose self-administration. Taken together, the findings indicate that IVM reduces alcohol intake across several different models of self-administration and suggest that IVM may be useful in the treatment of AUDs.
Collapse
Affiliation(s)
- Megan M Yardley
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, 1985 Zonal Avenue, Los Angeles, CA 90033, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Becker HC. Effects of alcohol dependence and withdrawal on stress responsiveness and alcohol consumption. Alcohol Res 2012; 34:448-58. [PMID: 23584111 PMCID: PMC3860383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
A complex relationship exists between alcohol-drinking behavior and stress. Alcohol has anxiety-reducing properties and can relieve stress, while at the same time acting as a stressor and activating the body's stress response systems. In particular, chronic alcohol exposure and withdrawal can profoundly disturb the function of the body's neuroendocrine stress response system, the hypothalamic-pituitary-adrenocortical (HPA) axis. A hormone, corticotropin-releasing factor (CRF), which is produced and released from the hypothalamus and activates the pituitary in response to stress, plays a central role in the relationship between stress and alcohol dependence and withdrawal. Chronic alcohol exposure and withdrawal lead to changes in CRF activity both within the HPA axis and in extrahypothalamic brain sites. This may mediate the emergence of certain withdrawal symptoms, which in turn influence the susceptibility to relapse. Alcohol-related dysregulation of the HPA axis and altered CRF activity within brain stress-reward circuitry also may play a role in the escalation of alcohol consumption in alcohol-dependent individuals. Numerous mechanisms have been suggested to contribute to the relationship between alcohol dependence, stress, and drinking behavior. These include the stress hormones released by the adrenal glands in response to HPA axis activation (i.e., corticosteroids), neuromodulators known as neuroactive steroids, CRF, the neurotransmitter norepinephrine, and other stress-related molecules.
Collapse
|
23
|
Roger-Sánchez C, Aguilar MA, Rodríguez-Arias M, Aragon CM, Miñarro J. Age- and sex-related differences in the acquisition and reinstatement of ethanol CPP in mice. Neurotoxicol Teratol 2011; 34:108-15. [PMID: 21843635 DOI: 10.1016/j.ntt.2011.07.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 07/28/2011] [Accepted: 07/29/2011] [Indexed: 11/30/2022]
Abstract
Many people begin to experiment with alcohol during adolescence, an important developmental period during which sex differences in the effects of ethanol appear. In the present study we evaluated the effect of ethanol (0, 0.625, 1.25 or 2.5 g/kg) on the acquisition of a conditioned place preference (CPP) in early and late adolescent male and female mice. In addition, we assessed the capacity of ethanol to induce reinstatement of the CPP after its extinction. CPP was induced in early and late adolescent females with 2.5 g/kg, and in early adolescent males with 1.25 or 2.5 g/kg of ethanol. No CPP was observed in late adolescent males. Priming with ethanol reinstated the CPP induced by the highest dose in early adolescent male and early and late adolescent female mice. Our data suggest that early adolescents of both sex and late adolescent females are particularly vulnerable to the effects of ethanol.
Collapse
Affiliation(s)
- C Roger-Sánchez
- Unidad de Investigación Psicobiología de las Drogodependencias, Departamento de Psicobiología, Facultad de Psicología, Universitat de Valencia, Avda. Blasco Ibáñez, 21, 46010 Valencia, Spain
| | | | | | | | | |
Collapse
|
24
|
Ramaker MJ, Ford MM, Fretwell AM, Finn DA. Alteration of ethanol drinking in mice via modulation of the GABA(A) receptor with ganaxolone, finasteride, and gaboxadol. Alcohol Clin Exp Res 2011; 35:1994-2007. [PMID: 21649668 DOI: 10.1111/j.1530-0277.2011.01551.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Neurosteroids and other γ-aminobutyric acid(A) (GABA(A) ) receptor-modulating compounds have been shown to affect ethanol intake, although their mechanism remains unclear. This study examined how patterns of 24-hour ethanol drinking in mice were altered with the synthetic GABAergic neurosteroid ganaxolone (GAN), with an inhibitor of neurosteroid synthesis (finasteride [FIN]), or a GABA(A) receptor agonist with some selectivity at extrasynaptic receptors (gaboxadol HCL [THIP]). METHODS Male C57BL/6J mice had continuous access to a 10% v/v ethanol solution (10E) or water. Using lickometer chambers, drinking patterns were analyzed among mice treated in succession to GAN (0, 5, and 10 mg/kg), FIN (0 or 100 mg/kg), and THIP (0, 2, 4, 8, and 16 mg/kg). RESULTS GAN shifted drinking in a similar but extended manner to previous reports using low doses of the neurosteroid allopregnanolone (ALLO); drinking was increased in hour 1, decreased in hours 2 and 3, and increased in hours 4 and 5 postinjection. THIP (8 mg/kg) and FIN both decreased 10E drinking during the first 5 hours postinjection by 30 and 53%, respectively, while having no effect on or increasing water drinking, respectively. All 3 drugs altered the initiation of drinking sessions in a dose-dependent fashion. FIN increased and GAN decreased time to first lick and first bout. THIP (8 mg/kg) decreased time to first lick but increased time to first bout and attenuated first bout size. CONCLUSIONS The present findings support a role for the modulation of ethanol intake by neurosteroids and GABA(A) receptor-acting compounds and provide hints as to how drinking patterns are shifted. The ability of THIP to alter 10E drinking suggests that extrasynaptic GABA(A) receptors may be involved in the modulation of ethanol intake. Further, the consistent results with THIP to that seen previously with high doses of ALLO suggest that future studies should further examine the relationship between neurosteroids and extrasynaptic GABA(A) receptors, which could provide a better understanding of the mechanism by which neurosteroids influence ethanol intake.
Collapse
Affiliation(s)
- Marcia J Ramaker
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon, USA.
| | | | | | | |
Collapse
|
25
|
Frye CA, Paris JJ, Osborne DM, Campbell JC, Kippin TE. Prenatal Stress Alters Progestogens to Mediate Susceptibility to Sex-Typical, Stress-Sensitive Disorders, such as Drug Abuse: A Review. Front Psychiatry 2011; 2:52. [PMID: 22022315 PMCID: PMC3195272 DOI: 10.3389/fpsyt.2011.00052] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 09/10/2011] [Indexed: 01/06/2023] Open
Abstract
Maternal-offspring interactions begin prior to birth. Experiences of the mother during gestation play a powerful role in determining the developmental programming of the central nervous system. In particular, stress during gestation alters developmental programming of the offspring resulting in susceptibility to sex-typical and stress-sensitive neurodevelopmental, neuropsychiatric, and neurodegenerative disorders. However, neither these effects, nor the underlying mechanisms, are well understood. Our hypothesis is that allopregnanolone, during gestation, plays a particularly vital role in mitigating effects of stress on the developing fetus and may mediate, in part, alterations apparent throughout the lifespan. Specifically, altered balance between glucocorticoids and progestogens during critical periods of development (stemming from psychological, immunological, and/or endocrinological stressors during gestation) may permanently influence behavior, brain morphology, and/or neuroendocrine-sensitive processes. 5α-reduced progestogens are integral in the developmental programming of sex-typical, stress-sensitive, and/or disorder-relevant phenotypes. Prenatal stress (PNS) may alter these responses and dysregulate allopregnanolone and its normative effects on stress axis function. As an example of a neurodevelopmental, neuropsychiatric, and/or neurodegenerative process, this review focuses on responsiveness to drugs of abuse, which is sensitive to PNS and progestogen milieu. This review explores the notion that allopregnanolone may effect, or be influenced by, PNS, with consequences for neurodevelopmental-, neuropsychiatric-, and/or neurodegenerative- relevant processes, such as addiction.
Collapse
Affiliation(s)
- Cheryl A Frye
- Department of Psychology, University at Albany-State University of New York Albany, NY, USA
| | | | | | | | | |
Collapse
|
26
|
Ford MM, Fretwell AM, Anacker AMJ, Crabbe JC, Mark GP, Finn DA. The influence of selection for ethanol withdrawal severity on traits associated with ethanol self-administration and reinforcement. Alcohol Clin Exp Res 2010; 35:326-37. [PMID: 21070250 DOI: 10.1111/j.1530-0277.2010.01348.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Several meta-analyses indicate that there is an inverse genetic correlation between ethanol preference drinking and ethanol withdrawal severity, but limited work has characterized ethanol consumption in 1 genetic animal model, the Withdrawal Seizure-Prone (WSP) and-Resistant (WSR) mouse lines selected for severe or mild ethanol withdrawal, respectively. METHODS We determined whether line differences existed in: (i) operant self-administration of ethanol during sucrose fading and under different schedules of reinforcement, followed by extinction and reinstatement of responding with conditioned cues and (ii) home cage drinking of sweetened ethanol and the development of an alcohol deprivation effect (ADE). RESULTS Withdrawal Seizure-Prone-1 mice consumed more ethanol than WSR-1 mice under a fixed ratio (FR)-4 schedule as ethanol was faded into the sucrose solution, but this line difference dissipated as the sucrose was faded out to yield an unadulterated 10% v/v ethanol solution. In contrast, WSR-1 mice consumed more ethanol than WSP-1 mice when a schedule was imposed that procedurally separated appetitive and consummatory behaviors. After both lines achieved the extinction criterion, reinstatement was serially evaluated following oral ethanol priming, light cue presentation, and a combination of the 2 cues. The light cue produced maximal reinstatement of responding in WSP-1 mice, whereas the combined cue was required to produce maximal reinstatement of responding in WSR-1 mice. There was no line difference in the home cage consumption of a sweetened ethanol solution over a period of 1 month. Following a 2-week period of abstinence, neither line developed an ADE. CONCLUSIONS Although some line differences in ethanol self-administration and reinstatement were identified between WSP-1 and WSR-1 mice, the absence of consistent divergence suggests that the genes underlying these behaviors do not reliably overlap with those that govern withdrawal severity.
Collapse
Affiliation(s)
- Matthew M Ford
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, 97239-3098, USA.
| | | | | | | | | | | |
Collapse
|
27
|
Besheer J, Lindsay TG, O'Buckley TK, Hodge CW, Morrow AL. Pregnenolone and ganaxolone reduce operant ethanol self-administration in alcohol-preferring p rats. Alcohol Clin Exp Res 2010; 34:2044-52. [PMID: 20946297 DOI: 10.1111/j.1530-0277.2010.01300.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Neuroactive steroids modulate ethanol intake in several self-administration models with variable effects. The purpose of this work was to examine the effects of the long-acting synthetic GABAergic neurosteroid ganaxolone and the endogenous neurosteroid pregnenolone, a precursor of all GABAergic neuroactive steroids, on the maintenance of ethanol self-administration in an animal model of elevated drinking-the alcohol-preferring (P) rats. METHODS P rats were trained to self-administer ethanol (15% v/v) versus water on a concurrent schedule of reinforcement, and the effects of ganaxolone (0 to 30 mg/kg, subcutaneous [SC]) and pregnenolone (0 to 75 mg/kg, intraperitoneal [IP]) were evaluated on the maintenance of ethanol self-administration. After completion of self-administration testing, doses of the neuroactive steroids that altered ethanol self-administration were assessed on spontaneous locomotor activity. Finally, the effect of pregnenolone administration on cerebral cortical levels of the GABAergic neuroactive steroid (3α,5α)-3-hydroxypregnan-20-one (allopregnanolone, 3α,5α-THP) was determined in both ethanol-experienced and ethanol-inexperienced P rats because pregnenolone is a precursor of these steroids. RESULTS Ganaxolone produced a dose-dependent biphasic effect on ethanol reinforcement, as the lowest dose (1 mg/kg) increased and the highest dose (30 mg/kg) decreased ethanol-reinforced responding. However, the highest ganaxolone dose also produced a nonspecific reduction in locomotor activity. Pregnenolone treatment significantly reduced ethanol self-administration (50 and 75 mg/kg), without altering locomotor activity. Pregnenolone (50 mg/kg) produced a significant increase in cerebral cortical allopregnanolone levels. This increase was observed in the self-administration trained animals, but not in ethanol-naïve P rats. CONCLUSIONS These results indicate that pregnenolone dose-dependently reduces operant ethanol self-administration in P rats without locomotor impairment, suggesting that it may have potential as a novel therapeutic for reducing chronic alcohol drinking in individuals that abuse alcohol.
Collapse
Affiliation(s)
- Joyce Besheer
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7178, USA
| | | | | | | | | |
Collapse
|
28
|
Anker JJ, Carroll ME. The role of progestins in the behavioral effects of cocaine and other drugs of abuse: human and animal research. Neurosci Biobehav Rev 2010; 35:315-33. [PMID: 20398693 DOI: 10.1016/j.neubiorev.2010.04.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Revised: 04/06/2010] [Accepted: 04/08/2010] [Indexed: 11/25/2022]
Abstract
This review summarizes findings from human and animal research investigating the influence of progesterone and its metabolites allopreganolone and pregnanolone (progestins) on the effects of cocaine and other drugs of abuse. Since a majority of these studies have used cocaine, this will be the primary focus; however, the influence of progestins on other drugs of abuse will also be discussed. Collectively, findings from these studies support a role for progestins in (1) attenuating the subjective and physiological effects of cocaine in humans, (2) blocking the reinforcing and other behavioral effects of cocaine in animal models of drug abuse, and (3) influencing behavioral responses to other drugs of abuse such as alcohol and nicotine in animals. Administration of several drugs of abuse in both human and nonhuman animals significantly increased progestin levels, and this is explained in terms of progestins acting as homeostatic regulators that decrease and normalize heightened stress and reward responses which lead to increased drug craving and relapse. The findings discussed here highlight the complexity of progestin-drug interactions, and they suggest a possible use for these agents in understanding the etiology of and developing treatments for drug abuse.
Collapse
Affiliation(s)
- Justin J Anker
- Department of Psychiatry, University of Minnesota, Minneapolis, MN 55455, USA.
| | | |
Collapse
|
29
|
Porcu P, O'Buckley TK, Alward SE, Song SC, Grant KA, de Wit H, Leslie Morrow A. Differential effects of ethanol on serum GABAergic 3alpha,5alpha/3alpha,5beta neuroactive steroids in mice, rats, cynomolgus monkeys, and humans. Alcohol Clin Exp Res 2009; 34:432-42. [PMID: 20028362 DOI: 10.1111/j.1530-0277.2009.01123.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Acute ethanol administration increases plasma and brain levels of progesterone and deoxycorticosterone-derived neuroactive steroids (3alpha,5alpha)-3-hydroxypregnan-20-one (3alpha,5alpha-THP) and (3alpha,5alpha)-3,21-dihydroxypregnan-20-one (3alpha,5alpha-THDOC) in rats. However, little is known about ethanol effects on GABAergic neuroactive steroids in mice, nonhuman primates, or humans. We investigated the effects of ethanol on plasma levels of 3alpha,5alpha- and 3alpha,5beta-reduced GABAergic neuroactive steroids derived from progesterone, deoxycorticosterone, dehydroepiandrosterone, and testosterone using gas chromatography-mass spectrometry. METHODS Serum levels of GABAergic neuroactive steroids and pregnenolone were measured in male rats, C57BL/6J and DBA/2J mice, cynomolgus monkeys, and humans following ethanol administration. Rats and mice were injected with ethanol (0.8 to 2.0 g/kg), cynomolgus monkeys received ethanol (1.5 g/kg) intragastrically, and healthy men consumed a beverage containing 0.8 g/kg ethanol. Steroids were measured after 60 minutes in all species and also after 120 minutes in monkeys and humans. RESULTS Ethanol administration to rats increased levels of 3alpha,5alpha-THP, 3alpha,5alpha-THDOC, and pregnenolone at the doses of 1.5 g/kg (+228, +134, and +860%, respectively, p < 0.001) and 2.0 g/kg (+399, +174, and +1125%, respectively, p < 0.001), but not at the dose of 0.8 g/kg. Ethanol did not alter levels of the other neuroactive steroids. In contrast, C57BL/6J mice exhibited a 27% decrease in serum 3alpha,5alpha-THP levels (p < 0.01), while DBA/2J mice showed no significant effect of ethanol, although both mouse strains exhibited substantial increases in precursor steroids. Ethanol did not alter any of the neuroactive steroids in cynomolgus monkeys at doses comparable to those studied in rats. Finally, no effect of ethanol (0.8 g/kg) was observed in men. CONCLUSIONS These studies show clear species differences among rats, mice, and cynomolgus monkeys in the effects of ethanol administration on circulating neuroactive steroids. Rats are unique in their pronounced elevation of GABAergic neuroactive steroids, while this effect was not observed in mice or cynomolgus monkeys at comparable ethanol doses.
Collapse
Affiliation(s)
- Patrizia Porcu
- Department of Psychiatry and Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7178, USA
| | | | | | | | | | | | | |
Collapse
|
30
|
Campbell JC, Szumlinski KK, Kippin TE. Contribution of early environmental stress to alcoholism vulnerability. Alcohol 2009; 43:547-54. [PMID: 19913199 DOI: 10.1016/j.alcohol.2009.09.029] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Revised: 05/06/2009] [Accepted: 08/11/2009] [Indexed: 11/29/2022]
Abstract
The most problematic aspects of alcohol abuse disorder are excessive alcohol consumption and the inability to refrain from alcohol consumption during attempted abstinence. The root causes that predispose certain individuals to these problems are poorly understood but are believed to be produced by a combination of genetic and environmental factors. Early environmental trauma alters neurodevelopmental trajectories that can predispose an individual to a number of neuropsychiatric disorders, including substance abuse. Prenatal stress (PNS) is a well-established protocol that produces perturbations in nervous system development, resulting in behavioral alterations that include hyperresponsiveness to stress, novelty, and psychomotor stimulant drugs (e.g., cocaine, amphetamine). Moreover, PNS animals exhibit enduring alterations in basal and cocaine-induced changes in dopamine and glutamate transmission within limbic structures, which exhibit pathology in drug addiction and alcoholism, suggesting that these alterations may contribute to an increased propensity to self-administer large amounts of drugs of abuse or to relapse after periods of drug withdrawal. Given that cocaine and alcohol have actions on common limbic neural substrates (albeit by different mechanisms), we hypothesized that PNS would elevate the motivation for, and consumption of, alcohol. Accordingly, we have found that male C57BL/6J mice subject to PNS exhibit higher operant responding and consume more alcohol during alcohol reinforcement as adults. Alterations in glutamate and dopamine neurotransmission within the forebrain structures appear to contribute to the PNS-induced predisposition to high alcohol intake and are induced by excessive alcohol intake. Accordingly, we are exploring the interactions between neurochemical changes produced by PNS and changes induced by consumption of alcohol in adulthood to model the biological bases of high vulnerability to alcohol abuse.
Collapse
Affiliation(s)
- Joannalee C Campbell
- Department of Psychology, University of California, Santa Barbara, CA 93106-9660, USA
| | | | | |
Collapse
|
31
|
Ford MM, Fretwell AM, Nickel JD, Mark GP, Strong MN, Yoneyama N, Finn DA. The influence of mecamylamine on ethanol and sucrose self-administration. Neuropharmacology 2009; 57:250-8. [PMID: 19501109 DOI: 10.1016/j.neuropharm.2009.05.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Revised: 05/28/2009] [Accepted: 05/29/2009] [Indexed: 11/18/2022]
Abstract
Neuronal nicotinic acetylcholine receptors (nAChRs) are believed to be critically involved in ethanol-related behaviors as well as in neurochemical responses to ethanol. However, discernment of nAChR contribution to ethanol reinforcement and consumption remains incomplete. The current studies examined the influence of the nAChR antagonist mecamylamine (MEC) on operant ethanol self-administration using a procedure that independently assessed appetitive and consumptive processes, and compared these findings to effects of MEC on sucrose self-administration. Male C57BL/6J (B6) mice were trained to respond for 30-min access to a retractable drinking tube containing either 10% v/v ethanol (10E) or 5% w/v sucrose (5S). Once trained, mice were habituated to saline injection and then treated with a series of MEC doses (0-8 mg/kg; i.p.) in a within-subject design. In a separate cohort, MEC was evaluated for its influence on locomotor activity. MEC dose-dependently reduced 10E and 5S self-administration. The suppression in ethanol intake was attributable to a reduction in bout frequency, whereas the attenuation in sucrose intake was due to a decrease in bout size. Doses of MEC (6-8 mg/kg) that altered drinking patterns were also found to impair locomotor activity. Although MEC non-selectively reduced 10E and 5S intakes in mice, there was some specificity in alterations of the underlying drinking pattern for each reinforcer. Assessment of drinking topography within an operant self-administration procedure may provide useful insights regarding the role of nAChR function in the regulation of ethanol consumption.
Collapse
Affiliation(s)
- Matthew M Ford
- Department of Behavioral Neuroscience (L-470), Oregon Health & Science University, Portland, OR 97239-3098, USA.
| | | | | | | | | | | | | |
Collapse
|