Ethanol administration produces divergent changes in GABAergic neuroactive steroid immunohistochemistry in the rat brain.

BACKGROUND The 5α-reduced pregnane neuroactive steroid (3α,5α)-3-hydroxypregnan-20-one (3α,5α-THP or allopregnanolone) is a potent positive modulator of GABAA receptors capable of modulating neuronal activity. In rats, systemic ethanol (EtOH) administration increases cerebral cortical and hippocampal levels of 3α,5α-THP, but the effects of EtOH on 3α,5α-THP levels in other brain regions are unknown. There is a large body of evidence suggesting that 3α,5α-THP enhances EtOH sensitivity, contributes to some behavioral effects of EtOH, and modulates EtOH reinforcement and motivation to drink. In this study, we used immunohistochemistry (IHC) to determine EtOH-induced changes in cellular 3α,5α-THP expression in brain regions associated with EtOH actions and responses. METHODS Male Wistar rats were administered EtOH (2 g/kg) or saline intraperitoneally and after 60 minutes transcardially perfused. IHC was performed on free-floating sections (3 to 4 sections/animal/brain region) using an affinity purified anti-3α,5α-THP primary antibody, and immunoreactivity was visualized with 3,3'-diaminobenzidine. RESULTS EtOH significantly increased 3α,5α-THP immunoreactivity by 24 ± 6% in the medial prefrontal cortex, 32 ± 12% in the hippocampal Cornu Ammonis area 1 (CA1) pyramidal cell layer, 52 ± 5% in the polymorph cell layer of the dentate gyrus (DG), 44 ± 15% in the bed nucleus of the stria terminalis, and 36 ± 6% in the paraventricular nucleus of the hypothalamus. In contrast, EtOH administration significantly reduced 3α,5α-THP immunoreactivity by 25 ± 5% in the nucleus accumbens "shore" and 21 ± 3% in the central nucleus of the amygdala. No changes were observed in the ventral tegmental area, dorsomedial striatum, granule cell layer of the DG, or the lateral and basolateral amygdala. CONCLUSIONS The results suggest acute EtOH (2 g/kg) produces divergent, brain region specific, effects on cellular 3α,5α-THP levels. Regional differences in the effects of EtOH suggest there may be regional brain synthesis of 3α,5α-THP independent of the adrenal glands and novel mechanisms that reduce cellular 3α,5α-THP. Regional differences in EtOH-induced changes in 3α,5α-THP levels likely contribute to EtOH effects on neuronal function in brain.

[1]  G. Stuber,et al.  New insights on neurobiological mechanisms underlying alcohol addiction , 2013, Neuropharmacology.

[2]  G. Koob.  Theoretical frameworks and mechanistic aspects of alcohol addiction: alcohol addiction as a reward deficit disorder. , 2013, Current topics in behavioral neurosciences.

[3]  S. Moss,et al.  Neurosteroidogenesis Is Required for the Physiological Response to Stress: Role of Neurosteroid-Sensitive GABAA Receptors , 2011, The Journal of Neuroscience.

[4]  Y. Izumi,et al.  Ethanol Enhances Neurosteroidogenesis in Hippocampal Pyramidal Neurons by Paradoxical NMDA Receptor Activation , 2011, The Journal of Neuroscience.

[5]  C. Hodge,et al.  Pregnenolone and ganaxolone reduce operant ethanol self-administration in alcohol-preferring p rats. , 2010, Alcoholism, clinical and experimental research.

[6]  A. Armario.  Activation of the hypothalamic-pituitary-adrenal axis by addictive drugs: different pathways, common outcome. , 2010, Trends in pharmacological sciences.

[7]  T. O’Buckley,et al.  Ethanol induction of steroidogenesis in rat adrenal and brain is dependent upon pituitary ACTH release and de novo adrenal StAR synthesis , 2010, Journal of neurochemistry.

[8]  M. Ford,et al.  Manipulation of GABAergic steroids: Sex differences in the effects on alcohol drinking- and withdrawal-related behaviors , 2010, Hormones and Behavior.

[9]  K. Grant,et al.  Differential Effects of Ethanol on Serum GABAergic 3 α ,5 α /3 α ,5 β Neuroactive Steroids in Mice, Rats, Cynomolgus Monkeys and Humans , 2010 .

[10]  E. C. Howard,et al.  The dopamine response in the nucleus accumbens core-shell border differs from that in the core and shell during operant ethanol self-administration. , 2009, Alcoholism, clinical and experimental research.

[11]  T. O’Buckley,et al.  Simultaneous quantification of GABAergic 3α,5α/3α,5β neuroactive steroids in human and rat serum , 2009, Steroids.

[12]  J. Steinbach,et al.  Mechanisms of neurosteroid interactions with GABA(A) receptors. , 2007, Pharmacology & therapeutics.

[13]  J. Lambert,et al.  Neurosteroid modulation of synaptic and extrasynaptic GABA(A) receptors. , 2007, Pharmacology & therapeutics.

[14]  M. Ford,et al.  Allopregnanolone influences the consummatory processes that govern ethanol drinking in C57BL/6J mice , 2007, Behavioural Brain Research.

[15]  Y. Saalmann,et al.  Cellular Distribution of the GABAA Receptor‐Modulating 3α‐Hydroxy, 5α‐Reduced Pregnane Steroids in the Adult Rat Brain , 2007 .

[16]  Y. Saalmann,et al.  Cellular distribution of the GABAA receptor-modulating 3alpha-hydroxy, 5alpha-reduced pregnane steroids in the adult rat brain. , 2007, Journal of neuroendocrinology.

[17]  D. Amaral,et al.  The dentate gyrus: fundamental neuroanatomical organization (dentate gyrus for dummies). , 2007, Progress in brain research.

[18]  Y. Saalmann,et al.  Neurosteroids involved in regulating inhibition in the inferior colliculus. , 2006, Journal of Neurophysiology.

[19]  Alastair M. Hosie,et al.  Endogenous neurosteroids regulate GABAA receptors through two discrete transmembrane sites , 2006, Nature.

[20]  Erminio Costa,et al.  Characterization of brain neurons that express enzymes mediating neurosteroid biosynthesis , 2006, Proceedings of the National Academy of Sciences.

[21]  M. Ford,et al.  Neurosteroid Modulators of GABAA Receptors Differentially Modulate Ethanol Intake Patterns in Male C57BL/6J Mice , 2005 .

[22]  R. Feinn,et al.  GABRA2 Alleles Moderate the Subjective Effects of Alcohol, Which are Attenuated by Finasteride , 2005, Neuropsychopharmacology.

[23]  R. Ugale,et al.  Evaluation of GABAergic neuroactive steroid 3α-hydroxy-5α-pregnane-20-one as a neurobiological substrate for the anti-anxiety effect of ethanol in rats , 2005, Psychopharmacology.

[24]  D. B. Matthews,et al.  Ethanol-induced elevation of 3α-hydroxy-5α-pregnan-20-one does not modulate motor incoordination in rats , 2004 .

[25]  R. Gonzales,et al.  The role of mesolimbic dopamine in the development and maintenance of ethanol reinforcement. , 2004, Pharmacology & therapeutics.

[26]  G. Biggio,et al.  Brain Steroidogenesis Mediates Ethanol Modulation of GABAA Receptor Activity in Rat Hippocampus , 2004, The Journal of Neuroscience.

[27]  A. Guidotti,et al.  Chronic intermittent ethanol (CIE) administration in rats decreases levels of neurosteroids in hippocampus, accompanied by altered behavioral responses to neurosteroids and memory function , 2004, Neuropharmacology.

[28]  G. Koob,et al.  Ethanol-induced increases in neuroactive steroids in the rat brain and plasma are absent in adrenalectomized and gonadectomized rats. , 2004, European journal of pharmacology.

[29]  D. B. Matthews,et al.  Ethanol-induced elevation of 3 alpha-hydroxy-5 alpha-pregnan-20-one does not modulate motor incoordination in rats. , 2004, Alcoholism, clinical and experimental research.

[30]  T. O’Buckley,et al.  Neuroactive steroid 3α-hydroxy-5α-pregnan-20-one modulates ethanol-induced loss of righting reflex in rats , 2003, Brain Research.

[31]  Hyun Joon Kim,et al.  StAR and steroidogenic enzyme transcriptional regulation in the rat brain: effects of acute alcohol administration. , 2003, Brain research. Molecular brain research.

[32]  P. Janak,et al.  Comparison of the effects of allopregnanolone with direct GABAergic agonists on ethanol self-administration with and without concurrently available sucrose. , 2003, Alcohol.

[33]  Sayaka Tokunaga,et al.  Effect of acute ethanol administration and acute allopregnanolone administration on spontaneous hippocampal pyramidal cell neural activity , 2003, Brain Research.

[34]  E. Seu,et al.  Progesterone enhances ethanol‐induced modulation of mesocortical dopamine neurons: antagonism by finasteride , 2002, Journal of neurochemistry.

[35]  C. Chopde,et al.  Behavioral action of ethanol in Porsolt’s forced swim test: modulation by 3alpha-hydroxy-5alpha-pregnan-20-one , 2002, Neuropharmacology.

[36]  Sayaka Tokunaga,et al.  Acute ethanol administration and acute allopregnanolone administration impair spatial memory in the Morris water task. , 2002, Alcoholism, clinical and experimental research.

[37]  M. Marinelli,et al.  The neurosteroid allopregnanolone increases dopamine release and dopaminergic response to morphine in the rat nucleus accumbens , 2002, The European journal of neuroscience.

[38]  W. Mcbride.  Central nucleus of the amygdala and the effects of alcohol and alcohol-drinking behavior in rodents , 2002, Pharmacology Biochemistry and Behavior.

[39]  D. B. Matthews,et al.  The role of GABAergic neuroactive steroids in ethanol action, tolerance and dependence , 2001, Brain Research Reviews.

[40]  S. Mellon,et al.  Biosynthesis of the Neurosteroid 3α-Hydroxy-4-pregnen-20-one (3αHP), a Specific Inhibitor of FSH Release. , 2001, Endocrinology.

[41]  S. Mellon,et al.  Biosynthesis of the neurosteroid 3 alpha-hydroxy-4-pregnen-20-one (3 alpha hp), a specific inhibitor of FSH release. , 2001, Endocrinology.

[42]  D. L. Robinson,et al.  Dissociation between the time course of ethanol and extracellular dopamine concentrations in the nucleus accumbens after a single intraperitoneal injection. , 2000, Alcoholism, clinical and experimental research.

[43]  D. B. Matthews,et al.  Neuroactive Steroid 3α-Hydroxy-5α-Pregnan-20-One Modulates Electrophysiological and Behavioral Actions of Ethanol , 2000, The Journal of Neuroscience.

[44]  G. Gessa,et al.  Ethanol markedly increases "GABAergic" neurosteroids in alcohol-preferring rats. , 1999, European journal of pharmacology.

[45]  A. Morrow,et al.  Effects of Chronic Ethanol Consumption and Withdrawal on the Neuroactive Steroid 3α‐Hydroxy‐5α‐pregnan‐20‐one in Male and Female Rats , 1998 .

[46]  P. Janak,et al.  The reinforcing effects of ethanol are altered by the endogenous neurosteroid, allopregnanolone. , 1998, Alcoholism, clinical and experimental research.

[47]  F. Holsboer,et al.  The Neurosteroid Tetrahydroprogesterone Attenuates the Endocrine Response to Stress and Exerts Glucocorticoid-like Effects on Vasopressin Gene Transcription in the Rat Hypothalamus , 1996, Neuropsychopharmacology.

[48]  G. Biggio,et al.  Inhibition of basal and stress-induced dopamine release in the cerebral cortex and nucleus accumbens of freely moving rats by the neurosteroid allopregnanolone , 1996, Journal of psychopharmacology.

[49]  G. Biggio,et al.  Time-dependent changes in rat brain neuroactive steroid concentrations and GABAA receptor function after acute stress. , 1996, Neuroendocrinology.

[50]  F. Holsboer,et al.  The neurosteroid tetrahydroprogesterone counteracts corticotropin-releasing hormone-induced anxiety and alters the release and gene expression of corticotropin-releasing hormone in the rat hypothalamus , 1994, Neuroscience.

[51]  C. Nemeroff,et al.  5a-Pregnane-3a,21-diol-20-one (THDOC) attenuates mild stress-induced increases in plasma corticosterone via a non-glucocorticoid mechanism: comparison with alprazolam , 1992, Brain Research.

[52]  S. Paul,et al.  Steroid hormone metabolites potentiate GABA receptor-mediated chloride ion flux with nanomolar potency. , 1987, European journal of pharmacology.

[53]  G. Di Chiara,et al.  Preferential stimulation of dopamine release in the nucleus accumbens of freely moving rats by ethanol. , 1986, The Journal of pharmacology and experimental therapeutics.