Sex-dependent effects of inescapable shock administration on behavior and subsequent escape performance in rats.

Stress-induced behavioral disturbances have widely been used as animal models of depression. Sex differences, however, have rarely been studied, even though evidence is available to show that males and females react differently after presentation of aversive stimuli. The present experiment investigated the behavioral effects of inescapable shocks on subsequent shuttlebox-escape performance in male and female rats. Exposure to inescapable shocks resulted in suppression of activity during shock administration, which was more severe when shock duration was increased. Females showed less behavioral suppression and they were also more active than males during the adaptation phase, prior to shuttlebox-escape training. Shuttlebox-escape performance was less affected in females than in males compared to that of nonshocked control subjects. Shock duration as a factor only affected efficiency of shuttlebox-escape performance in males.