Abstract

The effects of cocaine on male rat sexual behavior and sexual inhibition were studied. The first study addressed acute and long-term effects of cocaine (5, 10, 20, and 40 mg/kg, i.p.) on sexual responsiveness using a paradigm where cocaine was administered intermittently prior to sexual behavior and was followed by tests during withdrawal and drug challenge. The subsequent studies attempted to use the models of sexual inhibition described above to determine whether acute administration of cocaine could disrupt first-order and second-order conditioned inhibition of sexual behavior. Results indicated that cocaine administration lead to decreased ejaculation latencies compounded with fewer intromissions prior to ejaculation. The effects of cocaine (20 and 40 mg/kg, i.p.) on sexual inhibition were subsequently tested using first order and second order conditioned sexual inhibition paradigms. Cocaine did not release male copulatory behavior from inhibition, at any of the doses tested, on the inhibitory test with non-receptive females. In contrast, in an experiment in which males were conditioned to inhibit their sexual responses in the presence of a neutral odor (almond) paired with female non-receptivity, cocaine (20 mg/kg, i.p.) was shown to block the learned sexual inhibition against females bearing the odor in a copulatory preference test with two receptive females, as measured by the choice of first mount. Paradoxically, the same dose of cocaine (20 mg/kg, i.p.) also resulted in a preference to repeatedly mount the female bearing the odor associated with non-receptivity, as indicated by repeated attempts to mount. The present findings were interpreted in light of proposed links between cocaine use and sexual risk-taking reported in the human literature.