Bicuculline ameliorated chronic, but not acute, stress-induced feeding suppression

Abstract

This study was conducted to examine if ?-amino butyric acid (GABA)-ergic neurotransmission is implicated in the regulation of stress-induced feeding. Rats received GABAA receptor antagonist bicuculline before each stress session during 10 days of daily restraint stress. The hypothalamic mRNA expression of corticotropin-releasing hormone (CRH) and neuropeptide Y (NPY) was 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 CRH expression was blunted by bicuculline pre-treatment. Restraint stress did not affect NPY expression, regardless of bicuculline pre-treatment. It is concluded that GABAA receptors may mediate chronic, but not acute, stress-induced suppression in food intake, possibly in relation with anorectic action of the hypothalamic CRH, and the hypothalamic NPY may not be implicated in its regulatory mechanism.