Effect of pyrenzepine on gastric secretion in Shay rats.

: The degranulation of the gastric mastocytes, gastric cAMP levels and intragastric pH were studied in Shay rats after the intraduodenal administration of 20 mg/kg pyrenzepine chlorhydrate. There was a significant increase in the intragastric pH after the administration of this substance, reaching its maximum alkalization 120 min later. The cAMP levels decreased significantly and reached their lowest levels 60 min later. The possible antihistaminic effect of the drug was also studied. Pyrenzepine did not reduce the acid secretion induced by the subcutaneous administration of different doses of histamine. The results show that the decrease in the cAMP gastric levels and in the acid secretion was not due to an antihistaminic effect of pyrenzepine chlorhydrate.