Contractile reactivity of the perfused mesenteric vascular bed from sinoaortic denervated rats to norepinephrine, methoxamine and verapamil.

The contractile reactivity to norepinephrine, methoxamine, and verapamil of the perfused mesenteric vascular bed from sinoaortic denervated (SAD) and sham-operated (SO) rats was studied 3 to 30 days after surgery. A gradual but incomplete reduction of arterial hypertension was observed in SAD rats throughout the study. The norepinephrine- and methoxamine-induced dose-response curves were similar in both SAD and SO groups on day 3, but shifted to the left on days 7 and 15 and demonstrated a tendency to shift to the right at 30 days. Verapamil-induced vasodilation was similar in both groups. Enhanced mesenteric vascular responsiveness to endogenous catecholamines could contribute to the increased vascular resistance.