Effect of apomorphine, a dopamine receptor agonist, on penile tumescence in normal subjects.
Apomorphine HCl (Apo) (0.25, 0.5 or 0.75 mg sc), a dopamine (DA) receptor agonist, induced penile erections (PEs) (monitored by mercury strain gauges and continuous recording on paper strip charts) in 7 out of 9 normal subjects and placebo in 1 of these 9 (p less than 0.05). Apo-induced PEs recurred in each of the 6 subjects retested. Benztropine (2 mg iv) had no effect on Apo-induced penile tumescence (PT). These data suggest (a) DA mechanisms play a role in normal erectile function (b) DA-mediated PT is not modulated by cholinergic systems (c) evaluation of the erectile response to Apo may provide a simple ancillary test to the investigation of impotence and a way of identifying a subpopulation of impotent subjects with impaired DA function who may respond to long-acting DA agents (d) Apo-induced PT may provide a novel way of studying DA function in man.
D000328:Adult; D001058:Apomorphine / Q000494:pharmacology*; D001590:Benztropine / Q000494:pharmacology; D001971:Bromocriptine / Q000494:pharmacology; D002799:Cholinergic Fibers / Q000502:physiology; D004298:Dopamine / Q000502:physiology*; D004347:Drug Interactions; D006801:Humans; D007980:Levodopa / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D010413:Penis / Q000187:drug effects* / Q000502:physiology
D001590:Benztropine; D001971:Bromocriptine; D007980:Levodopa; D001058:Apomorphine; D004298:Dopamine