Effect of vasopressin on canine gastric mucosal circulation.

Continuous intravenous infusion of small doses of vasopressin (0.05 microgram/kg/h) in anaesthetized dogs was effective in reducing gastric mucosal flow, whereas moderate doses (0.2 micrograms/kg/h) induced a substantial flow reduction. Larger doses of vasopressin (2-4 micrograms/kg/h) precipitated massive gastric flow reduction with subsequent hyperaemia, which was not effectively controlled by moderate vasopressin doses. The effect of intraportal infusion of vasopressin on mucosal flow was similar to that of intravenous infusion. Prolonged intravenous infusion of moderate vasopressin doses maintained mucosal flow reduction over extended periods. The implications of the findings are discussed with particular reference to clinical use of vasopressin as a means of controlling bleeding from gastric mucosal lesions in patients.