TY - JOUR AU - MIAO Hui AU - XIAO Wen-bin AU - QIN Bo-yi PY - 2016 TI - Effects of 7-methoxy-4'-hydroxyl-3'-diethylaminomethylisoflavone on heart atrium and ventricular papillary muscles of guinea pig JF - Acta Pharmacologica Sinica; Vol 11, No 4 (July 1990): Acta Pharmacologica Sinica Y2 - 2016 KW - N2 - In isolated guinea pig right atria, 7-methoxy-4'-hydroxyl-3'-diethylaminomethylisoflavone (MHDF), a new synthetic isoflavone produced noncompetitive antagonisms to isoproterenol- and histamine-induced positive chronotropic actions with pD'2 values of 5.04 +/- 0.10 and 4.90 +/- 0.18, respectively. MHDF inhibited the positive chronotropic response to CaCl2. In isolated left atria, the negative inotropic action of MHDF increased as the frequency increased. In papillary muscles, MHDF 3 mumol/L reduced the contractile force, while Vmax was decreased and APD and ERP were prolonged. These results indicated that the mechanism of MHDF on myocardium is related to inhibition of Ca2+ influx, Na+ influx and K+ efflux, not by blocking beta or H2 receptors. UR - http://www.chinaphar.com/article/view/5646