Canine esophageal motor function: effects of arterial and intravenous vasopressin

The effect of vasopressin infusion on esophageal motor function was evaluated in 11 anesthetized dogs. Gastric fundic, lower esophageal sphincteric, and esophageal body pressures were measured during and after 1 hr infusion of vasopressin into the superior mesenteric artery or a systemic vein. Lower esophageal sphincteric pressures started to decrease significantly 10-15 min after the start of vasopressin infusion, reached the lowest level at 45-60 min, and returned to the control level or higher 1 hr after the end of infusion. No statistically significant difference was found between the effects of intravenous and intraarterial vasopressin infusions. Esophageal body and gastric fundic pressures remained unchanged. The result is inconsistent with the hypothesis that esophageal smooth muscle contractions reduce esophageal variceal hemorrhage during vasopressin infusions.