Sexual Behavior in Male Rats After Radiofrequency or Dopamine-Depleting Lesions in Nucleus Accumbens

Abstract

Considerable neurochemical evidence links dopamine (DA) in nucleus accumbens (NAcc) to male sexual behavior. The present experiments were conducted to extend this information to the male’s sexual response to remote stimuli from estrous female (noncontact erection; NCE). Male rats were tested for copulation and NCE after either 6-hydroxydopamine (6-OHDA) or radiofrequency (RF) lesions in NAcc). Males with an average 78% depletion of DA in NAcc had a lower incidence of NCE, longer latency to display NCE, and fewer erections. DA-depleted males also had less locomotor activity after injections of d-amphetamine, and reductions in apomorphine-induced yawning, but a normal incidence of penile erection. Males with RF lesions of the NAcc had longer NCE latencies. All males copulated to ejaculation after either 6-OHDA or RF lesions with little or no deficit, although the 6-OHDA–treated males had longer intromission latencies. The NCE deficit supports the hypothesized role of NAcc DA in arousal processes in responding to remote cues from estrous females. The minimal effect of lesions on copulation suggests that the presence of additional proximal stimulation during copulation may overcome the deficits induced by DA depletions or lesions in NAcc.