Verapamil and nifedipine effects on gastric acid secretion and ulcer formation in rats.

The calcium channel antagonists verapamil and nifedipine were examined for their effects on conscious basal gastric acid output, stress ulcer formation and on ethanol-induced ulcers. Both compounds significantly reduced gastric acid secretion, however verapamil did so in a dose-related manner. Both verapamil and nifedipine significantly attenuated stress gastric ulcer formation. Nifedipine, at a dose of 32.0 mg kg-1, virtually abolished stress ulcers. Verapamil exacerbated, while nifedipine, at 32.0 mg kg-1, attenuated ethanol-induced gastric ulcers. The differential gastrointestinal effects of these calcium channel antagonists support the existence of multiple classes of calcium channels in the gut and suggest an important role for intracellular calcium and hence, its blockade, in gastric pathophysiology.