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Coregulation of Ethanol Discrimination by the Nucleus Accumbens and Amygdala
Author(s) -
Besheer Joyce,
Cox Amy A.,
Hodge Clyde W.
Publication year - 2003
Publication title -
alcoholism: clinical and experimental research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.267
H-Index - 153
eISSN - 1530-0277
pISSN - 0145-6008
DOI - 10.1097/01.alc.0000057036.64169.c1
Subject(s) - nucleus accumbens , amygdala , muscimol , extended amygdala , neuroscience , basal ganglia , chemistry , gabaa receptor , agonist , endocrinology , medicine , pharmacology , receptor , psychology , biology , dopamine , central nervous system , biochemistry
Background: Activation of GABA A receptors in the amygdala or nucleus accumbens produces discriminative stimulus effects that substitute fully for those of systemically administered ethanol. This study was conducted to determine if GABA A receptors in the amygdala and nucleus accumbens interactively modulate ethanol discrimination. Methods: Male Long‐Evans rats were trained to discriminate between intraperitoneal injections of ethanol (1 g/kg) and saline on a 2‐lever drug discrimination task. The rats were then surgically implanted with bilateral injection cannulae aimed at the nucleus accumbens and the amygdala. Results: Infusion of the GABA A agonist muscimol in the nucleus accumbens resulted in full substitution for systemically administered ethanol. Concurrent infusion of the GABA A antagonist bicuculline in the amygdala shifted the muscimol substitution curve in the nucleus accumbens 10‐fold to the right. Conclusions: These results indicate that blockade of GABA A receptors in the amygdala significantly reduces the potency of the GABA A agonist in the nucleus accumbens. This suggests that the ethanol‐like stimulus effects of GABA A receptor activation in the nucleus accumbens are modulated by GABA A receptor activity in the amygdala. These data support the hypothesis that the addictive stimulus properties of alcohol are mediated by GABAergic transmission in a neural circuit involving the amygdala and nucleus accumbens.