DOSE DEPENDENT D2 EFFECTS ON GENITAL REFLEXES AFTER MPOA INJECTIONS OF QUINELORANE AND APOMORPHINE

This study investigated the effects on genital reflexes of unilateral MPOA injections of 0.1, 1, 3, and 10-mu-g of the D2 agonist quinelorane (LY-163502), and of 3-mu-g quinelorane administered together with 3-mu-g of the D1 antagonist SCH-23390. In addition, the effects of an MPOA injection of 10-mu-g apomorphine were tested. All but the lowest dose of quinelorane significantly decreased the latency to the first reflex. The 3 and 10-mu-g doses of quinelorane, and the combination of quinelorane and SCH-23390, decreased the total number of reflexes. In addition, 10-mu-g quinelorane increased the number of seminal emissions. 10-mu-g apomorphine, like 10-mu-g quinelorane, decreased the latency to the first reflex and increased the number of seminal emissions, but did not decrease the numbers of erections or penile movements. The ratio of D1/D2 activity may influence the number of erections displayed during ex copula testing.