Studies on the mechanism of diarrhoea induced by Escherichia coli heat-stable enterotoxin (STa) in newborn calves.

作者: A.M. Al-Majali , E.K. Asem , C.H. Lamar , J.P. Robinson , M.J. Freeman

DOI: 10.1023/A:1006444105846

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摘要: Enterotoxigenic Escherichia coli (ETEC) produces a heat-stable enterotoxin (STa) that binds to and activates putative intestinal receptor, guanylate cyclase, causing an increase in the intracellular levels of cyclic guanosine monophosphate (cGMP). Using flow cytometry 125I-STa binding assays, we studied distribution STa-receptors on enterocytes isolated from different segments newborn calf's tract. We also investigated effect STa cGMP ion transport lumen. More were found prepared ileum than obtained other Guanylate cyclase activity was higher STa-challenged calves control calves. No changes observed Na+ levels, as measured by atomic absorption spectroscopy, significantly increased luminal contents calves, whereas serum Cl- lower This study supports previous observations role initiation STa-induced secretory diarrhoea suggests Na+/Cl- coupling may be major mechanism for loss ions diarrhoeal response is mostly induced

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