Effects of histamine, acetylcholine, and norepinephrine on gastric vascular resistance

Abstract

The vasoactive properties of three naturally occurring substances which influence gastric secretion were investigated in the gastric vascular bed. A constant flow perfusion of the canine stomach was employed and vascular pressures were recorded in response to a wide range of drug doses. Histamine was found to decrease vascular resistance appreciably in the concentration range 0.01–0.50 µg/ml blood perfusing the stomach. Gastric vascular resistance declined in response to acetylcholine infusion when the concentration exceeded 0.10 µg/ml blood. Norepinephrine increased resistance to blood flow appreciably when perfusion concentration was greater than 0.05 µg/ml blood. It was also found that the responses to histamine and norepinephrine were esssentially the same whether the agents were infused locally or systemically for calculated concentrations in the gastric perfusate. These findings substantiate the concept that gastric secretory stimulants dilate, and that gastric secretory inhibitors constrict the gastric vascular bed.