The effects of intrathecal administration of the dopamine agonist apomorphine on penile reflexes and copulation in the male rat.
Relatively high doses of systemically administered apomorphine inhibit penile reflexes. It is possible that these inhibitory effects are due, at least in part, to actions of apomorphine on the lumbosacral spinal cord. The present experiments examined this possibility by injecting apomorphine (10 and 50 micrograms/5.0 microliters vehicle) into the lumbosacral subarachnoid space through chronic, indwelling cannulae. Such injections impaired ex copula penile reflexes, slowed the rate of copulation, and decreased the number of intromissions preceding ejaculation. These results suggest that lumbosacral cord dopamine receptors may normally regulate male sexual performance.
Pehek
E A
EA
Department of Psychology, State University of New York, Buffalo 14260.
Thompson
J T
JT
Hull
E M
EM
D000818:Animals; D001058:Apomorphine / Q000008:administration & dosage / Q000494:pharmacology*; D003307:Copulation / Q000187:drug effects*; D015259:Dopamine Agents / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D007278:Injections, Spinal; D008297:Male; D010413:Penis / Q000187:drug effects*; D051381:Rats; D012018:Reflex / Q000187:drug effects*; D013346:Subarachnoid Space / Q000033:anatomy & histology
D015259:Dopamine Agents; D001058:Apomorphine