Effects of regional vasopressin infusion of intestinal series-coupled vascular sections

The effects induced by infusion of vasopressin into the superior mesenteric artery on the small intestinal series-coupled vascular sections were studied in cats and compared to those evoked by stimulation of the regional sympathetic nerves. The doses used were similar to those recommended for clinical purposes. Vasopressin induced an increase in intestinal resistance to blood flow, which at higher doses was biphasic with an initial pronounced effect followed after a few min by a less marked steady state response. Vasopressin induced no effect on the intestinal capillary filtration coefficient, did not change the isovolumetric equilibrium and evoked only a minor decrease in regional blood volume. When compared with sympathetic nerve stimulation the latter induced a less marked steady state increase in intestinal blood flow resistance but a more pronounced decrease in regional blood volume and a decrease in capillary filtration coefficient. The effects following vasopressin infusion were in the doses used not that pronounced that they could be considered potentially harmful for the small intestinal tissue.