Responsiveness of duodenal smooth muscle to histamine and carbachol following Escherichia coli infection in chickens

The contractile responses of the duodenal segments from healthy and Escherichia coli infected broiler chickens on exposure to exogenous histamine and carbachol were studied. Molar concentrations of the agonists were introduced into suspensions of the segments in Tyrodes solution at 37 o C and the responses recorded using kymograph. Both healthy and infected segments responded dose-dependently to the agonists. The healthy segments showed greater sensitivity to the agonists and produced significantly (P<0.05) higher mean maximum responses in all cases. The threshold responses to molar concentrations of the drugs were lower for segments from infected chickens. It is suggested that E. coli infection may have altered the contractile responses of chicken