Excitatory and inhibitory effects of stimulation applied during the postejaculatory interval of the male rat

Abstract

The male rat's sexual responsiveness to stimuli applied during the postejaculatory interval (PEI) was examined in two experiments. Experiment 1 was a test of the hypothesis that sexual behavior could be facilitated by presenting a novel female to a male during the final, but not the initial portions of the PEI. Although female variation is known to rearouse a sexually sated male, the same manipulations performed either early or late in the PEI, but prior to sexual exhaustion, were without effect. In Expt 2, the responses of male rats to mild electric shocks applied at different points in the PEI were studied. Shocks delivered soon after ejaculation (during the hypothetical absolute refractory period) delayed the resumption of copulation. Stimulation applied later in the PEI (during the relative refractory period) facilitated a resumption of sexual behavior. It was determined that the facilitative consequences of shock are transitory, persisting for a matter of seconds; the inhibitory effects may be evident for several minutes.