Effects of tetrandrine on various vascular smooth muscles

Abstract

A comparison of the effects of tetrandrine (Tet) on 7 isolated vascular strips of rabbits was made. The influence of Tet, verapamil (Ver) and phentolamine (Phen) on noradrenaline (NA) concentration-response curves was also studied. Tet inhibited the contraction evoked by high-K⁺ in thoracic aortic strips and more prominently in mesenteric arterial strips. Phen antagonized NA competitively, while Tet and Ver antagonized NA in a noncompetitive manner. Calcium was also antagonized by Tet and Ver noncompetitively. These findings suggest that Tet and Ver resemble each other in inducing relaxation on vascular smooth muscles, which results from their antagonism to calcium.

Keywords

tetrandrine / verapamil / phentolamine / vascular strins / drug concentration-response relationship / calcium channel blockers

References

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