Contraction induced by Clostridium perfringens alpha toxin in the isolated rat ileum

Clostridium perfringens alpha toxin caused contraction of the isolated rat ileum in a dose-dependent manner. The contraction caused by the toxin was inhibited by verapamil, nifedipine, cinnarizine, but not by tetrodotoxin or incubation in a low Na+ medium. The toxin stimulated Ca2+ uptake in the ileum in a dose-dependent manner. Nifedipine completely inhibited the Ca2+ uptake into the ileum induced by the toxin. Furthermore, TMB-8, trifluoperazine, W-7 and H-7 significantly blocked the toxin-induced contraction. On the other hand, the toxin activated de novo production of phosphatidic acid and phosphatidylinositol in the tissue. These data suggest that the toxin-induced contraction is due to an increased Ca2+ permeability across the tissue, and activation of phospholipid metabolism.