Vasoconstriction reactions in tail artery in the rats with regional arterial hypotension

Reactivity of the tail artery to norepinephrine was studied in rats with regional arterial hypotension. Constant-flow perfusion of the artery elicited less pronounced constriction in hypotensive rats in comparison with the controls, while the constant-pressure perfusion evoked stronger vasoconstriction. This is explained by possible involvement of myogenic component in the contractile response. When myogenic reaction was inhibited by enhanced potassium concentration in the perfusion solution, vasoconstriction in hypotensive rats was less pronounced under both perfusion modes.[PUBLICATION ABSTRACT]