Effects of benzyltetrahydropalmatine on alpha, beta and other receptors
Zhang, J.S.; Huang, Z.Y.; Yao, W.X.; Xia, G.J.; Jiang, M.X.
Yao Xue Xue Bao 23(9): 641-645
1988
ISSN/ISBN: 0513-4870 PMID: 2855684 Document Number: 308082
Benzyltetrahydropalmatine (BTHP) produce parallel shift of the cumulative dose-response curves for phenylephrine in rabbit aortic strips and rat anococcygeus muscles to the right. Their PA2 values were found to be 5.8 and 5.86 respectively. In pithed rats, the dose-response curves of methoxamine and B-HT 920 were not altered by BTHP 5.apprx.10 mg/kg which could increase the diastolic pressure. However, the rise in DP was not blocked by yohimbine 1.apprx.2 mg/kg. In isolated spontaneously beating quinea pig atria, the positive chronotropic action of both Iso and His can be antagonized by BTHP in a non-competitive manner. The pD2' value for Iso was shown to be 4. In addition, the arrhythmia induced by reperfusion in rats was also antagonized by BTHP 5 mg/kg. These results suggest that the blocking action of BTHP on a1- and .beta.-adrenoceptors and H2-receptor are probably partially associated with its antiarrhythmic action.