Copulatory behavior of male rats given intermittent electric shocks: theoretical implications.

Abstract

In 3 experiments mildly painful .5-sec. shocks, delivered to the skin of male rats every 30 sec. in the presence of a receptive female, reduced the intervals between intromissions and the latencies to resume mounts and intromissions after ejaculation (PEM, PEI), but did not affect the number of intromissions preceding ejaculation. The effects of shock on PEM and PEI supported Beach and Holz-Tucker's concept of the postejaculatory period consisting of absolute and relative phases. The pattern of results led to the development of a model of the fluctuation in sexual arousal during copulation and to a modification of existing theories of the accumulation of ejaculatory potential. The copulatory behavior of male rats includes brief penile insertions spaced a minute or so apart. After several such intromissions the male, during the next insertion, ejaculates. Following ejaculation there is a period of 5 min. or more before the male again attempts copulation with the female. This copulatory behavior can be potentiated by a number of arousing nonsexual stimuli, including striking the male (Beach, 1942), lifting the male and replacing him gently (Larsson, 1963), or applying painful peripheral shocks (Barfield & Sachs, 1968; Caggiula & Eibergen, 1969). The facilitative effects of peripheral shock are manifested in several changes in the normal parameters of the male's sexual behavior. Analysis of these changes reveals implica