How sexual behavior in male rats is inhibited by repeated maternal separation during early postnatal development

Abstract

Perinatal stress can have lasting effects on hormone regulation and behavior. An association between maternal separation and depressive illness is well established. The present study was undertaken to investigate the effects of maternal separation on both motivational and consummatory measures and on the temporal patterning of sexual behavior in male rats. Litters were separated from their mothers for 180 min per day from P1 to P21 (birth=P0) and placed in an isolated box. Control litters remained with their mothers and were not disturbed. At 90 days of age, the sexual behavior of the male rats was assessed using both standard behavioral parameters and mount bout analysis. The forced swim test, open field test, and elevated plus maze test were used to assess anxious and depressive behavior. Each rat was subjected to a single type of behavioral protocol. The inhibitory effect of maternal separation on the sexual behavior of male rats was shown by an increase in mount, intromission, and ejaculation latencies, mount and intromission frequency, and interintromission interval, and a decrease in intromission ratio. Maternally separated rats showed a delayed temporal patterning of sexual behavior. In addition, there was an increase in depressive and anxiety-like behavior in maternally separated rats. The present results suggest that perinatal stress induced by maternal separation leads to changes in sexual behavior and depressive and anxiety-like behavior in male rats. In this sense, early postnatal stress may cause behavioral changes that persist into adulthood.