Role of Sympathetic Pathway in Secretory Activity Induced in Rat Parotid by Feeding 1

Abstract

Summary

A prominent role for the sympathetic inanervation in the secretory activity reflexly induced in parotid gland during eating is shown by present data. This role is concerned principally with the secretion of proteins, e.g., amylase. Parotid glands of rats fasted overnight to establish maximal glandular levels of the enzyme were stimulated by eating solid (but not liquid) diet; measurements of amylase activity made 1 hr later showed a 26% decrease in amylase activity of the gland. If atropine, in low dose, was administered just prior to the refeeding, there was no inhibition of the emptying; if propranolol and dibenzyline were administered prior to refeeding, the emptying was inhibited. Thus, the emptying of gland amylase induced by eating solid food is mediated through the sympathetic pathway. Cholinergic stimulation, either by feeding, by direct electrical stimulation of the auriculotemporal nerve, or by injection of a parasympathomimetic agent, produced little alteration of gland levels of enzyme. On the other hand, adrenergic stimulation had a profound effect in causing depletion of gland levels of amylase that was apparent from direct electrical stimulation of the sympathetic innervation, from use of pilocarpine and from experiments with refeeding of solid chow.