Effect of Enterotoxins of Vibrio cholerae, Escherichia coli, and Shigella dysenteriae Type 1 on Fluid and Electrolyte Transport in the Colon

Abstract

Experiments were designed to determine whether the enterotoxins of Vibrio cholerae, Escherichia coli, and Shigella dysenteriae type 1. alter the movement of fluid and electrolytes in the rat cecum. Net secretion of water and sodium were observed after incubation of 1.67 × 10⁻⁵ µg of purified cholera toxin (choleragen)/ml for 18 hr or of 50 µg/ ml for 3 hr. The effect of choleragen on cecal transport of water and electrolytes was related to the dose. In addition, choleragen increased cecal mucosal content of adenosine 3′:5′-cyclic phosphate but did not alter the histology of the cecum. The results demonstrate that the colon responds to choleragen in a manner similar to that. of. other tissues. In contrast, the enterotoxins of both E. coli and S. dysenteriae type 1 failed to affect cecal transport of water and electrolytes. These observations may explain several phenomena associated with the diarrhea produced by bacterial enterotoxins.