| Study on calcium channel blocking effect of dihydromyricetin on isolated rabbit aortic strips Graduate: Yang Yingxin Supervisor: Prof Zhou Xuexian Hunan College of TCM, Department of Pharmacology Changsha, 410007 Abstract Objective: To elucidate the mechanism of vasodlatation of dihydromyricetin (Dih) in Tengcha of Yao nation. Methods: The effects of Dih were studied on the contraction of isolated rabbit aortic strips agonized by noradrenaline (NA), KCI and CaCL2. The fluctuation of the concentration-response curves was observed; Effects of Dih on ci -adrenoceptor or f3 -adrenoceptor and influences of Dih on the 2 components of NA-evoked contraction were studied. Results: Dih was found to inhibit the contractions evoked by NA, KC1 and CaC12 in rabbit aortic strips. Dih shifted the concentration-response curves of NA, KCI and CaCI2 to the right, and depressed their maximal responses. Dih 2 produced neither ~1 -adrenoceptic blocking nor ~ -adrenoceptic stimulating effects. Dih-induced relaxation on vascular smooth muscle resulted from its calcium channel blocking and the mode of this mechanism had some differences from that of Verapamil. Dih inhibited both the receptor operated channel and potential dependent channel. On the contrary, Vcr inhibited the potential dependent channel only. Conclusion: The mechanism of vasodlatation of Dih is related to its blocking effect on calcium channel. |
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