Evidence for regionally selective changes in response to potassium chloride but not vasopressin or methoxamine in vasculature from diabetic rats.

In the present study we examined the contractile responses of aortae and mesenteric and femoral arteries taken from rats treated 3 weeks previously with streptozotocin (55 mg/kg, i.v.) or saline (1 mL/kg, i.v.) to vasopressin, potassium chloride, and methoxamine. The dose-response curves obtained with vasopressin and methoxamine were not significantly different between control and diabetic animals. However, both the diabetic mesenteric and femoral arteries showed a significantly (p less than 0.05) greater maximum response to potassium chloride as compared with their respective controls. The reactivity of the diabetic aortae to this agonist was not different. It is concluded that while the contractile responses of the diabetic tissues were normal when the agonist was vasopressin or methoxamine, there would appear to be regionally selective changes in responsiveness to potassium chloride.