Sweat Secretion Produced by Pilocarpine in the Cat. ∗

Abstract

Completely denervated sweat glands may be made to secrete by pilocarpine (Langley and Anderson, 1 Langley 2 ), in spite of the fact that section of a peripheral nerve may lead to a much diminished secretion, which Burn 3 attributed to the section of the somatic motor fibers rather than to the sensory or sympathetic fibers in the nerve. Burn believed that this was due to circulatory effects produced by muscular inactivity and found that it paralleled the decreased vasodilator response to histamine. Furthermore he found that pilocarpine following deafferentation of the hind limb in the cat produced a diminished response, accompanying the decreased movement and impaired circulation that was present for a time following the operation. This diminution disappeared later on. Burn, 3 , 4 further showed that the exaggerated sweat response following sympathectomy was due mainly to the removal of the sympathetic control of the blood vessels and also in some animals to a hypersensitiveness of the denervated glands and vessels to pilocarpine.

Guttmann 5 has reviewed the literature on this problem of sweat secretion in man and has described it as seen in a number of Foerster's patients. He has suggested that the sweat glands have a secretory innervation through the sympathetic chain as well as directly by way of the ventral roots to the spinal nerves, and an inhibitory innervation by way of the dorsal roots (Dieden 6 ). Langley 7 denied vigorously that there could be any direct secretory innervation to sweat glands aside from that passing through the sympathetic chain in the cat. He also found a facilitory instead of an inhibitory effect in the cat on stimulation of the 6th and 7th lumbar dorsal roots in case the secretion was already in progress, due, he thought, to the presence of the accompanying dorsal root vasodilatation.