Guo S R, Zhou E F
Department of Pharmacology, Shanxi Medical College, Taiyuan, China.
Zhongguo Yao Li Xue Bao. 1990 May;11(3):232-5.
Methylflavonolamine hydrochloride (4'-methyl-7-(2-hydroxy-3-isopropylamino-propoxy)-flavone hydrochloride, MFA) is a new compound synthesized by Shanghai Institute of Pharmaceutical Industry in China. Its effects on the fast and evoked slow response action potentials of isolated guinea pig papillary muscles have been studied by intracellular microelectrode techniques. The data were automatically analysed by a microcomputer system. At concentrations of 5-75 mumol/L, MFA caused a significant decrease in the duration required for 30, 50, 90% repolarization and a shift in the plateau to more negative transmembrane potentials. MFA 5 mumol/L had no effect on the maximal upstroke velocity during phase 0 (Vmax) but decreased it at 75 mumol/L. MFA had no significant effects on other AP parameters. It significantly inhibited the slow AP induced by isoprenaline or histamine (1 mumol/L) after myocardial cells were depolarized in high K+ (25 mmol/L) solution. The results suggest that MFA inhibits the inward Ca2+ current and at high concentration inhibits also the Na+ current.
盐酸甲基黄酮胺（4'-甲基-7-(2-羟基-3-异丙氨基丙氧基)-黄酮盐酸盐，MFA）是中国上海医药工业研究院合成的一种新化合物。已采用细胞内微电极技术研究了其对离体豚鼠乳头肌快速和诱发的慢反应动作电位的影响。数据由微机系统自动分析。在5 - 75μmol/L浓度下，MFA使30%、50%、90%复极化所需时间显著缩短，平台期向更负的跨膜电位偏移。5μmol/L的MFA对0期最大上升速度（Vmax）无影响，但在75μmol/L时使其降低。MFA对其他动作电位参数无显著影响。在高钾（25 mmol/L）溶液中使心肌细胞去极化后，它能显著抑制异丙肾上腺素或组胺（1μmol/L）诱发的慢动作电位。结果表明，MFA抑制内向Ca2+电流，高浓度时也抑制Na+电流。
