Choline-Esterase Content of Normal and Denervated Submaxillary Gland of the Cat. ∗

Abstract

The heightened sensitivity of the cat's submaxillary gland to sympathetic stimulation, following degenerative section of the chorda tympani, appears to be due to some spontaneous activity of the decentralized parasympathetic supply, the phenomenon thus being analogous to the well-known “augmented secretion”. 1 Histological examination of the unstimulated paralytic gland, indeed, reveals changes characteristic of activity in the demilune cells, 2 which are normally controlled by the sympathetic. 3 An attractive hypothesis is that the latter elements are sensitized by acetylcholine which is liberated elsewhere in the gland through the spontaneous activity of the postganglionic neurones, and which reaches the demilune cells by diffusion. After degenerative section of the chorda tympani, however, there is no increase, but a decrease, in the acetylcholine equivalent of the submaxillary gland. 4 Since the latter term includes both combined and free acetylcholine, it might still be possible that in the paralytic gland there is a higher concentration of the free ester. Thus it might be thought that denervation impairs the ability of the gland to inactivate acetylcholine which has been liberated within it, by reducing the gland's supply of choline-esterase.

Choline-esterase occurs in different tissues, as well as in the blood, in widely varying concentrations, the richest sources being, in general, those organs possessing a cholinergic innervation. 5 There has hitherto been no evidence to indicate whether or not the amount present in any organ is affected by section of the nerve supply to the organ. I have therefore made a series of determinations of the rate at which acetylcholine is destroyed by simple extracts of paralytic, as compared with normal, submaxillary glands.