title: [Effects of 7-methoxy-4'-hydroxyl-3'-diethylaminomethylisoflavone on heart atrium and ventricular papillary muscles of guinea pig].
abstract: 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.
authors.affiliation: Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing, China.
authors.forename: H
authors.initials: H
authors.lastname: Miao
authors.forename: W B
authors.initials: WB
authors.lastname: Xiao
authors.forename: B Y
authors.initials: BY
authors.lastname: Qin
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D016275:Atrial Function; D003864:Depression, Chemical; D005260:Female; D006168:Guinea Pigs; D006325:Heart Atria / Q000187:drug effects; D066298:In Vitro Techniques; D007529:Isoflavones / Q000494:pharmacology*; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D010210:Papillary Muscles / Q000187:drug effects*
chemical_list: D007529:Isoflavones; C068771:7-methoxy-4'-hydroxy-3'-diethylaminomethylisoflavone