Evidence for a Nonneural Electrogenic Effect of Cholera Toxin on Human Isolated Ileal Mucosa

Cholera toxin-induced intestinal secretion inintact rats requires a functioning myenteric plexus. Theaim of this investigation was to determine whetherneural elements were essential for cholera toxin to produce a secretory effect in human isolatedileum. Mucosal preparations were mounted in Ussingchambers. Cholera toxin was applied apically andshort-circuit current monitored for 3 hr, at which point forskolin was given. Cholera toxin (10μg/ml) induced a tetrodotoxin-insensitive increase inshort-circuit current in muscle-stripped preparations ofhuman ileum. The increase was not additive with the action of forskolin (25 μM). Cholera toxinexerts a marked nonneural secretory effect in humanileal mucosa in vitro , probably by the same mechanismas forskolin, namely elevation of cyclic AMP.