Distribution and Arteriovenous Shunting of Gastric Blood Flow in the Baboon: Effect of Epinephrine and Vasopressin Infusions

The effects of 60-min intraarterial infusion of vasopressin (0.005 U per kg-min) and epinephrine (0.05 μ per kg-min) on gastric hemodynamics were studied in anesthetized baboons. Total gastric blood flow was measured electromagnetically and radioactive microspheres (15 ± 5 μ) with three labels were used to determine regional distribution of gastric blood flow and arteriovenous shunting. Control flow was 55 ± 8 ml per min, with 77.4 ± 2.7% of flow going to the gastric mucosa and 1.7 ± 0.4% of injected spheres appearing in the liver. Epinephrine infusion resulted in a sustained vasoconstriction to 18 ± 5 ml per min with no autoregulatory escape and no changes in arterial pressure or cardiac output. Vasopressin resulted in a decrease in flow to 14 ± 3 ml per min with no escape. Whereas cardiac output did not change, there was a significant hypertensive effect during the vasopressin infusion. There was neither redistribution of flow nor change in arteriovenous shunting with either epinephrine or vasopressin. Transmucosal electrical potential difference was 62 ± 8 mv and did not change significantly with either infusion.