The contractile behaviour and effects of several autonomic drugs on the motor activity of human isolated ejaculatory ducts were investigated. Ejaculatory 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 increase in basal tone and in the frequency of the contraction waves. These effects were suppressed by atropine (10-4 m). Noradrenaline (norepinephrine) increased the basal tone and frequency of spontaneous contractions in a dose-dependent manner. These responses were competitively inhibited by HEAT, a selective a1-adrenoceptor antagonist. These preliminary functional findings, indicating the presence of spontaneous motor activity of human ejaculatory ducts and its possible control by adrenergic agonists, suggests a physiological role for human ejaculatory duct in the propulsion of semen from the seminal vesicle towards the urethra.