Bicuculline Ameliorated Chronic, but not Acute, Stress-Induced Feeding Suppression

Abstract

This study was conducted to examine if γ-amino Butyric Acid (GABA)-ergic neurotransmission is implicated in the regulation of stress-induced feeding. Rats received GABAAreceptor antagonist bicuculline before each stress session during 10 days of daily restraint stress. The hypothalamic mRNA expressions of corticotropin-releasing hormone and neuropeptide Y were analyzed by in situ hybridization and the plasma corticosterone with radioimmunoassay. Bicuculline ameliorated the decrease in food intake by repeated restraints but not by a single restraint. Corticosterone increase responding to acute stress but not to repeated restraints was attenuated by bicuculline. Stress-induced expression of corticotropin-releasing hormone was blunted by bicuculline pre-treatm ent. Restraint stress did not affect neuropeptide Y expression, regardless of bicuculline pre-treatment. It is concluded that GABAAreceptors may mediate chronic but not acute, stress-induced suppression in food intake, possibly in relation with anorectic action of the hypothalamic corticotropin-releasing hormone and the hypothalamic neuropeptide Y may not be implicated in its regulatory mechanism.