Function specific supersensitivity of m-chlorophenyl piperazine-induced serotonergic neurotransmission in female compared to male rats.

Administration of various doses of m-chlorophenylpiperazine (m-CPP), a 5-hydroxytryptamine (5-HT) agonist, to rats increased plasma levels of corticosterone and decreased locomotor activity in a dose dependent manner. The increases of plasma corticosterone but not the decreases of locomotor activity were greater in female than male rats. Hypophagic effects of m-CPP not different in freely feeding male and female rats were greater in females when food deprived animals used. The findings along with our previous report show a functional supersensitivity of 5-HT neurotransmission involved in the regulation of hypothalamo-pituitary adrenocortical axis and appetite suppression in female sex, and suggest a possible basis for the greater occurrence of depression and anorexia in women than men.