SIMILARITY OF EFFECTS OF ADRENALIN AND INHIBITORY SYMPATHIN ON INTESTINAL MOTILITY; SENSITIZATION BY DENERVATION

Abstract

By the use of dogs each having both an innervated and a denervated intestinal loop with fistula, and by interrupting both the sympathetic and the parasympa-thetic pathways at 2 different levels additional evidence has been obtained that inhibitory sympathin is produced during rectal stim. An amount of sympathin sufficient to inhibit the denervated intestine could be produced after coeliac ganglionectomy. Sympathin production after these procedures would have to occur in connection with organs innervated from the inferior mesenteric ganglion. All of the effects on intestinal motility of reflexly produced inhibitory sympathin were duplicated by injections of adrenalin at constant rates. Therefore, the possibility was indicated that the transmission of impulses from adrenergic sympathetic nerves to the wall of the intestine could be accounted for entirely by the producion of adrenine at the nerve endings. Direct evidence was obtained that a denervated Thiry fistula is much more sensitive to adrenalin than is an innervated Thiry fistula of the same dog. Estimated concs. of adrenalin in blood between 1 to 500,000,000 to 1 to 1,000,000,000 have marked inhibitory effects on the motility of the denervated intestine.