In vitro effects of wood creosote on enterotoxin-induced secretion measured electrophysiologically in the rat jejunum and colon

Secretory diarrhea occurs when the balance between intestinal absorption an d secretion is disturbed by excessive secretion caused by enterotoxins prod uced by the pathogen, Wood creosote has long been used as a traditional ant idiarrheal remedy. The goal of our study was to extend our knowledge about the antisecretory action of wood creosote against Escherichia coli enteroto xin-induced secretion in the small intestine and colon, Experiments were pe rformed in mucosal sheets of rat jejunum and colon which were stripped of t he external muscle layers to eliminate interactions with smooth muscle acti vity and local blood how, Mucosal sheets were placed in modified Ussing cha mbers and hypersecretory conditions were induced by heat-labile (LT) or hea t-stable (STa) E, coli enterotoxins added cumulatively (0.01-10 mug/ml) to the mucosal bathing solution. Intestinal secretion was monitored electrophy siologically as transmucosal short circuit current (Isc), LT induced a conc entration-dependent increase in Isc in the rat jejunum, with no effect in t he colon. In contrast, STa induced a significant increase in colonic Isc, w ithout causing any change in Isc across the jejunum, In separate experiment s the effects of increasing concentrations of wood creosote (0.1-50 mug/ml) , added to the mucosal or serosal bathing solution, were examined against t he secretory responses induced by LT or STa, In the small intestine the ant isecretory activity of wood creosote against LT-induced secretion was more potent following serosal application, whereas in the colon wood creosote in hibited STa-induced secretion with equal potency following either serosal o r mucosal addition, In summary, our findings demonstrate that wood creosote possesses antidiarrheal activity suppressing E, coli enterotoxin-induced s ecretion in both the small intestine and colon.