Effects of olfactory bulb removal and flank shock on copulation in male rats

Abstract

Sexually experienced male rats received bilateral olfactory bulbectomy (BOB, N=9), unilateral olfactory bulbectomy (UOB, N=7) or a sham operation (Sham, N=8). Copulation was severely disrupted in BOB males, whereas only minimal effects on copulation were observed in UOB males. Penile reflexes were not affected by either operation. Intermittent flank shock stimulated copulation in 5/6 BOB males. The BOB males that ejaculated had longer intromission latencies and longer postejaculatory intromission intervals than did Sham males receiving a similar schedule of shocks. Even so, all BOB males that ejaculated with flank shock also resumed copulation and ejaculated a second time without further shocks. Three BOB males that ejaculated with flank shock were tested the following week without shock, and none of these males copulated. These results strengthen previous conclusions that the olfactory bulbs are critical for the initiation and maintenance of sexual arousal in male rats.