Post-weaning social isolation alters the development of behavioral indices of sexual maturation and leads to deficits in the sexual behavior of male rats

Abstract

In male rats, genital grooming (GG) and spontaneous penile erections (SPE) increase substantially between weaning and the peripubertal period, and show a characteristic development pattern around the time of puberty. These indices of sexual maturation, which play an important role in readying adult male rats for reproduction, are influenced by several factors, such as drugs, undernutrition, maternal care, and social interaction. Considering that post-weaning social isolation affects sexual behavior, the aim of this work was to characterize the development pattern of GG, SPE and sexual behavior in male rats that were housed individually from 22-to-77 days of age. Although the values for the frequency and duration of GG and SPE showed a gradual increase as puberty approached (40 days old), social deprivation altered the relation of the occurrence of GG and SPE and the efficacy of sexual behavior. The subjects housed individually after post-weaning did not show a direct correlation between a higher frequency and duration of GG and SPE and improved performance of sexual behavior, as has been reported to occur in socially- housed male rats. These findings highlight the role of post-weaning social experience in the development of behavioral indices of sexual maturation, and suggest an important long-term effect on the performance of sexual behavior in the male rat.