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. Experimental Physiology (2000) 85.4, 465-467.