Differences in brain area 5-hydroxytryptamine turnover and rearing behavior in rats and mice of both sexes.

Abstract Rats and mice of both sexes were compared as to rearing behavior and 5-hydroxytryptamine (5-HT) turnover in forebrain and areas caudal to this. Turnover rates were calculated from changes in 5-HT metabolism in animals pretreated with the monoamine oxidase inhibitor, pargyline (75 mg/kg, i.p.). The results indicate that the female of each species has both a more functional 5-HT system and a higher rate of rearing. These data were interpreted on the basis that 5-HT systems normally depress the ability of an animal to habituate to a novel environment.