不同剂量维生素D3对心肌细胞电活动的影响

维生素D_可使豚鼠心室乳头肌细胞APA、OS、RP和Vmax降低,APD缩短,以APD50尤为明显,并随维生素D_3剂量增加而作用增强。该变化主要是通过细胞膜慢通道,使细胞内Ca~(2+)超负荷来实现的。

Effects of the Different Doses Vitamin D_3 on the Electrical Activities of the Guinea Pig Papillary Muscle Cells

The effects of the different doses vitamin D3 on the electrical activities of the cardiac cells were observed and recorded from isolated ventricular papillary muscles in guinea pig by means of the standard glass microelectrode technique and microcomputer system, thus exploring its influence on the membrane ionic current, infering the possible mechanism responsible for Ca2+ produced myocardial injury.The results showed that vitamin D3 made the APA, OS,RP and Vmax of the papillary muscle cells in the guinea pig decreased, the APD shortened, especially the APD50 was shortened most obviously, and with the incerase of vitamin D3 dose, the effects were strengthened.In view of these changes, the electrophysiological effects of vitamin D3 on myocardial cells are probably based on influencing the slow channel, increasing influx of Ca2+ and making the introcellular C2+ overload, therefore producing the myocardial injury.