Electrophysiological Properties of AARL in Guinea Pig Left Atrium
Du Zhimin,YangBaofeng(Clinical and Pharmaceutical Institute)(Department of Pharmacology)
We used electrophysiological techniques to examine the electrophysiological properties of AARL (S-(-)-6-chloro-2, 2-dimethyl-1′-[3-(4-hydroxypiperizino)propyl] spiro[chroman-4, 4′-imidazolidine]- 2′, 5′-dione, AARL), a novel antiarrhythmic agent,on transmembrane action potentials of isolated guinea pig left atrium. AARL produced a dose-dependent decrease in the maximum upstroke velocity of the action potential duration overshoot and amplitude at stimulated rates of 1 Hz,2 Hz and 3.3 Hz. The influences of AARL at the stimulated rate of 3.3 Hz on Vmax and OS were more potent than that of at 1,2 Hz.These may be a main cause of the drug in the supperesion of atrial arrhythmias,the resting potential was not affected by the drug even at the 30 μmol/L concentration studied.The absence of any effects of AARL on resting. potential implied that the Na/K pump may be not affected.AARL (3 to 30 μmol/L)at stimulated rate of 1 Hz reduced siagificantly APD following the agent, however, rapid rates, 3.3 Hz greatly enhancel APD The action of AARL, which prolonged or restored APD towards normal with dose-and time-dependence, which play probably central role in the anti-atrial arrhythmic action of the drug.It was proved that APD90, APD50 and APD20, were decreased markedly about 5 to 15 min following the drug, after that,APD tended to be lenthened,these indicated that AARL might interrupt the slow channels in guinea pig left atrium.
【CateGory Index】： R972.2