Effects of enkephalins and their analogs on gastric secretion

The effects of enkephalin analogs on gastric secretion were studied. It was found that gastric secretion stimulated by histamine was significantly increased under the influence of the enkephalin analog Tyr-D-Ala-Gly-Phe-(NO2)NH2. The enkephalin analog Tyr-Gly-Gly-Phe-Leu-D-Arg increased the amount of gastric juice and the secretion of pepsin, but the hydrochloric acid debit was lower than in experiments with perfusion of histamine alone. Another enkephalin analog, Tyr-D-Ala-Gly-Phe-D-Leu-Arg, introduced simultaneously with histamine, significantly lowered the secretion of gastric juice only 90-105 min after the beginning of perfusion.