Structure of the myenteric plexus in the sphincters of cat gastro-intestinal tract.. II. Changes in the quantitative characteristics of the types of dense-core vesicles after reserpine treatment.

In order to elucidate the functional significance of the populations of dense-core vesicles in the myenteric plexus of the sphincters of cat gastro-intestinal tract, studies are made of the changes in their spatial density after reserpine treatment, since the action of reserpine on a definte transmitter-noradrenaline-is known. The different character and intensity of the changes in the density of the different populations of dense-core vesicles probably indicates participation in the metabolism of different transmitter systems. The lack of statistically significant changes in the number of large dense-core vesicles correlates well with the character of the relaxation upon electrical stimulation of the sphincters and suggests participation of these vesicles in the nonadrenergic noncholinergic innervation.