Effect of various stimulants and inhibitors of gastric acid secretion on mucosal potential difference in man.

Pentagastrin and histamine in doses effective in stimulating gastric acid secretion (5 microgram/kg/h intravenously and 25 microgram/kg intramuscularly, respectively) produce a significant decrease in the gastric mucosal potential difference (PD) in man. In contrast, atropine and cimetidine (2 mg/30 min intravenously and 4.5 mg/kg/h intravenously respectively) cause a significant increase in gastric PD. The subsequent or simultaneous administration of cimetidine reverses the effect of the stimulating agents on gastric PD and pH. Similarly, the subsequent administration of pentagastrin reverses the effect of atropine. The intragastric instillation of 100 c HCl 0.1 N increases significantly the gastric PD valuesp in this case the patterns of PD and pH changes are dissimilar. This study indicates that substances that modify gastric acid secretion also induce changes in gastric PD; this last effect does not seem to depend on variations of the intragastric pH. Therefore, in the clinical evaluation of the gastric PD in man, its multifactorial origin must alway be considered.