Effects of furyl-dihydropyridine on action potential ventricular myocardium of rabbit in vivo and isolated guinea pig left atrium in vitro
Liu, D.Q.; Zhou, S.S.; Zhao, D.H.; Sheng, B.H.
Zhongguo Yao Li Xue Bao 14(2): 164-167
1993
ISSN/ISBN: 0253-9756 PMID: 8352012 Document Number: 413415
Effects of furyl-dihydropyridine (FDP) on action potential of rabbit ventricular myocardium in vivo were observed with floating microelectrode technique. FDP 0.5 mg cntdot kg-1 iv increased APD-30 from 104 +- 7 to 127 +- 7 ms, APD-90 from 146 +- 10 to 177 +- 9 ms (P lt 0.01, n = 7), decreased the heart rate from 230 +- 18 to 203 +- 20 bpm (P lt 0.05). Nifedipine (Nif) 0.5 mg cntdot kg-1 iv reduced APD and increased the HR in rabbit. In guinea pig left atrium, FDP and Nif decreased the APD, the effects of acetylcholine to shorten the APD was antagonized by FDP 1 mu-mol cntdot L-1. In rabbit's sinoatrial nodes, FDP 0.5, 1 mu-mol cntdot L-1 also suppressed the APA and increased the spontaneous sinus cycle length (SCL) and APD-50. These results indicate that FDP may inhibit the Ca-2+ and K+ currents of myocardium.