DOPAMINERGIC DRUGS IN THE MEDIAL PREOPTIC AREA AND NUCLEUS-ACCUMBENS - EFFECTS ON MOTOR-ACTIVITY, SEXUAL MOTIVATION, AND SEXUAL PERFORMANCE

In two experiments, dopamine agonists and/or antagonists were injected into the medial preoptic area (MPOA) or the nucleus accumbens (NAcc) of male rats. The animals were then tested in an X-maze with four goal boxes, which contained a receptive female, a male, or were empty. In Experiment 1, the D-1 antagonist SCH-23390 and the D-2 antagonist racl opride in the MPOA decreased the percentage of trials on which the fem ale's chamber was chosen, a measure of sexual motivation. Raclopride a lso decreased the number of animals that copulated after choosing the female's chamber. The 10-mu g dose of the D-3/D-2 agonist quinelorane increased the latency to reach the female's chamber, slowed the onset of copulation, and decreased the number of intromissions preceding an ejaculation. In Experiment 2, 1- and 5-mu g doses of quinelorane and o f the mixed D-1/D-2 agonist apomorphine were injected bilaterally into the NAcc. Both doses of quinelorane increased the number of times tha t the subject did not select a chamber within 60 s. No drug in the NAc c affected specifically sexual motivation or performance. The results are consistent with differential influence of the MPOA and the NAcc on motor activity, sexual motivation, and sexual performance.