Sex and strain differences in leverpress shock escape behavior

Abstract

In Experiment I, the performance of male and female Wistar albino and Long Evans hooded rats was compared on a leverpress shock escape procedure. Consistent superiority of Long-Evans over Wistar subjects emerged in measures of escape latency and percentage of session time spent in contact with the lever. Lower escape latencies recorded for females confirmed previous reports of better performance by female compared to male subjects in aversive conditioning procedures. The data suggest the overall advantage of using female Long Evans subjects, despite the fact that this group seldom appear as subjects in the aversive control literature. Experiment II replicated the sex differences in escape latency of normal subjects, but produced a striking reversal in the behavior of castrated animals. The escape latencies of castrated males and females differed significantly from those of their normal counterparts, and castrated males escaped shock more rapidly than castrated females. Results are discussed in terms of gonadal influences on pituitary-adrenal activity, which may underlie the form of escape response required in the present procedure.