Effects of adrenaline, noradrenaline and isoprenaline on the electrical and mechanical responses of the guinea-pig vas deferens to nerve stimulation.

Abstract

AbstractSjöstrand, N. O. Effects of adrenaline, noradrenaline and isoprenaline on the electrical and mechanical responses of the guinea‐pig vas deferens to nerve stimulation. Acta physiol. scand. 1973. 89. 10–18.The effect of noradrenaline, adrenaline and isoprenaline on the electrical and mechanical responses of the guinea‐pig vas deferens to nerve stimulation was studied with the sucrose gap technique. A stimulatory α‐adrenergic effect was found. This was due to a depolarization of the smooth muscle cell membrane. An inhibitory β‐adrenergic effect was observed in some preparations. It consisted of a hyperpolariiSation of the membrane potential and a decrease in size of the excitatory junction potentials. Thirdly, in a few preparations an inhibition of the excitatory junction potentials was seen, which was not a β‐effect but could partly be antagonized by phentolamine. It is suggested that this effect is due to an n‐sympathicomimitic inhibition of the neurotransmission in the vas deferens.