Effect of Autonomic Blocking Agents on Sweat Secretion in Cat

Abstract

Using a quantitative electrical technique, the effects of atropine and Dibenamine (N,N-dibenzyl-beta-chlorethylamine hydrochloride) on sweat gland activity were studied in cats under pentobarbital anesthesia. The sweat glands of the footpad were excited by single-shock stimulation of the lumbar sympathetic chain (L5-L6), and the electrical responses of the sweat glands were recorded through electrodes on the footpad and gland-free skin of the thigh. The potentials were recorded unamplified on a string galvanometer, or on a Hathaway galvanometer after suitable amplification with a carrier-type D.C. amplifier. Responses were evoked at 1-min. intervals before, during and after intraven. infusion of drugs. Dibenamine, a specific adrenolytic and sympatholytic drug, was given in dosages of 15-20 mg./kg. and at a slow rate (1 mg./min.) to avoid precipitous hypotension. Atropine (0.1 mg./kg.) was admd. rapidly. Dibenamine in doses sufficient to cause miosis, relaxation of mictitating membrane, and blockage of tail piloerection to sympathetic chain stimulation failed to reduce the potential responses of the sweat glands during infusion and for periods of an hr. after full dosage. The potentials often increased in magnitude, perhaps as a result of circulatory effects of the drug. Atropine promptly (4-5 min.) abolished the responses irreversibly. The results confirm Dale and Feldberg''s finding that the sudo-motor innervation is cholinergic and gave no evidence of a recently described adrenergic component.