Vascular reactivity in hypertension: altered effect of ouabain.

Ouabain inhibits the relaxing effect of Ca2+ (but not of Mn2+) on contractile responses in tail artery strips isolated from spontaneously hypertensive and normotensive rats. The magnitude of ouabain inhibition was greater in vascular strips from hypertensive rats suggesting a significant difference in basic membrane function in hypertensive vascular smooth muscle.