Effects of adrenergic and cholinergic drugs on electrical and mechanical activities of the rat cauda epididymidis in vitro

Summary. Electrical and mechanical activities of the rat epididymis (at 29 \m=+-\1\m=.\1cm from the junction of the vas deferens) were recorded in vitro. The frequency of the spontaneous activity was 2\m=.\7\m=+-\0\m=.\15/min.Adrenaline, phenylephrine, isoprenaline and carbachol increased the basal tension, frequency and amplitude of the contractions. Phentolamine, an alpha-adrenergic blocking agent, abolished the stimulatory effects of adrenaline and isoprenaline, but not those of carbachol. Propranolol and metoprolol, beta-adrenergic blocking agents, did not inhibit the stimulatory effects of isoprenaline. Atropine abolished the response to carbachol. The results suggest that alpha-adrenergic receptors but not beta-receptors are present in the rat epididymis.