Effects of proton pump inhibitors and histamine H2 receptor antagonists on gastrointestinal motility

ABSTRACT

Isolated segments from the different parts of the gastrointestinal tract of rabbit were used. They were suspended in organ bath containing physiological solution of PH7.4 at 37C and bubbled with air. Motility was recorded using isotonic transducter and an ossilograph. The effects of the proton pump inhibitor Omeprazole [5 UM] and the histamine H2 receptor antagonist Ranitidine [3 x 10-4 M] were studied. It was observed that Omeprazole decreases esophageal tone, decreases the amplitude of contractions in stomach and duodenum and decreases both bone and amplitude of contractions in the colon. This inhibitory effect of Omeprazole is abolished by either propranolol or phentolamine indicating an adrenergic effect of Omeprazole. The increased tone is a cholinergic effect since it is abolished by atropine. But the increased amplitude of contractions is not affected by atropine and is aboliahed in calcium free solution indicating that this effect of Ranitidine is due to increased calcium influx from the extracellular fluid