Human ejaculatory duct: parameters of smooth muscle motor activity and modulatory role of autonomic drugs

The contractile behaviour and effects of several autonomic drugs on the mot or activity of human isolated ejaculatory ducts were investigated. Ejaculat ory ducts exhibited spontaneous contractions characterised by an amplitude of 2.35 +/- 0.28 mN, a duration of 62.9 +/- 3.72 s and a frequency of 0.64 +/- 0.014 waves min(-1), Acetylcholine (10(-5)-10(-4) M) induced a slight i ncrease in basal tone and in the frequency of the contraction waves. These effects were suppressed by atropine (10(-4) M). Noradrenaline (norepinephri ne) increased the basal tone and frequency of spontaneous contractions in a dose-dependent manner. These responses were competitively inhibited by HEA T, a selective alpha(1)-adrenoceptor antagonist. These preliminary function al findings, indicating the presence of spontaneous motor activity of human ejaculatory ducts and its possible control by adrenergic agonists, suggest s a physiological role for human ejaculatory duct in the propulsion of seme n from the seminal vesicle towards the urethra.