Some effects of pilocarpine and acetylcholine on the responses of the guinea-pig vas deferens to hypogastric nerve stimulation and transmural stimulation and applied (–)-noradrenaline

Abstract

Enhancement by acetylcholine and by pilocarpine of the contractile responses of the guinea-pig isolated vas deferens to hypogastric nerve and transmural stimulation and to exogenous (–)-noradrenaline was examined. At high concentration (600 nm) acetylcholine enhanced responses in the order: hypogastric nerve > transmural > exogenous (–)-noradrenaline. Pilocarpine produced a similar maximal degree of enhancement with all three stimuli. All these effects were reversibly inhibited by 1.4 μta atropine, a concentration which alone did not affect responses to the stimuli. Pilocarpine (50–400 μm) gave a concentration-related inhibition of the enhancement of responses to hypogastric nerve stimulation by 600 nm acetylcholine.