Facilitation of copulatory behavior by pCPA treatments following stria terminalis transection but not medial amygdala lesion in the male rat.

In this study, we examined the effect of p-chlorophenylalanine (pCPA), a serotonin synthesis inhibitor, on masculine sexual behavior in male rats following bilateral medial amygdala lesions (MAL) or bilateral stria terminals cuts (STC). Males with MAL and STC both showed a suppression of sexual behavior, compared to that of sham-operated males, when injected with saline. On the other hand, intraperitoneal injections of pCPA increased mount and intromission frequencies in males with STC. Although pCPA injections also slightly increased mount frequency in males with MAL, the injections failed to affect intromission behavior in MAL males. These suggest that the stria terminalis is insufficient as pathway of a whole output of the medial amygdala in regulating copulatory behavior. The medial amygdala may be involved in some other function, such as erection, than that of the stria terminalis.