Effects and bioassay of Escherichia coli enterotoxin (heat-stable fraction) on smooth muscle |
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| Authors: | L Pesti HA Gordon |
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| Institution: | Department of Pharmacology, College of Medicine, University of Kentucky, Lexington, Ky. 40506 U.S.A. |
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| Abstract: | Heat-stable E. coli and V. cholerae enterotoxins and E. coli endotoxin were tested on the following smooth muscle preparation: vascular; rabbit aorta; rat mesenteric arterioles, and intestinal, rabbit jejunum; pig duodenum; dog jejunal lamina propria smooth muscle. The results indicated that in most preparations used, the prime action of heat-stable enterotoxin from pathogenic strains of E. coli consisted in neutralizing the effects of both alpha or beta adrenergic agonists. In this respect the effect of enterotoxin appeared similar to that of alpha or beta adrenergic blockers. Using the same models, it was found that this enterotoxin did not interfere with the effects of cholinergic agonists or of biogenic amines. Control heat-stable enterotoxin preparations and other tested substances proved inactive, suggesting that different receptor sites might exist for these agents in our models. It appears that smooth muscle preparations are well suited for bioassay of active heat-stable E. coli enterotoxin. |
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