Influence of atropine, pirenzepine and cimetidine on nocturnal gastro-intestinal motility and gastric acid secretion.

The present study was performed to investigate the correlation between gastric H-ion-concentration and interdigestive motility (1) under basal conditions and (2) under the influence of pirenzepine, atropine and cimetidine. During the control period 6.5 (DZ1 5, DZ9 12) MMC's per 12-hour periods (69 +/- 7% gastrointestinal MMC's) were recorded. After administration of pirenzepine and the combination of pirenzepine and cimetidine almost exclusively gastrointestinal MMC's could be identified. On the other hand, atropine did not change the gastrointestinal/intestinal MMC ratio, but reduced total number of MMC's significancy (p less than 0.05). Percentage of observation time with antral pH greater than 4 was significantly increased by the combination of pirenzepine and cimetidine, but not by pirenzepine or cimetidine alone nor by atropine. There was a positive correlation between interdigestive cycle-length and percentage of time with antral pH greater than 4. The effect of pirenzepine on interdigestive motility (1) seems not to be mediated by the inhibition of gastric acid and (2) is different from the effect of atropine.