McCall D
Cardiovasc Res. 1978 Sep;12(9):529-36. doi: 10.1093/cvr/12.9.529.
The effects of procainamide and lignocaine, in concentrations from 10(-6) to 10(-2) mol.litre(-1), on the Na influx and contraction frequency of cultured heart cells were studied. Both drugs produced a prompt, dose-dependent reduction in Na influx which was significant (P less than 0.01) for all concentrations tested. Lignocaine affected only that portion of the Na influx which was also verapamil-sensitive, whereas procainamide suppressed in addition, the verapamil-insensitive influx. In addition both drugs produced a concomitant decrease in the spontaneous contraction frequency of the cells. A close linear correlation (r = 0.99) between verapamil-sensitive Na influx and contraction frequency, in the presence of both procainamide and lignocaine was found. From this, and previous studies indicating a dependency of contraction frequency on the inward verapamil-sensitive Na influx, it is suggested that the drugs modify the automaticity of this preparation by a primary influence on membrane Na exchange.
研究了浓度范围为10⁻⁶至10⁻²mol·L⁻¹的普鲁卡因胺和利多卡因对培养心肌细胞钠内流和收缩频率的影响。两种药物均能迅速产生剂量依赖性的钠内流减少，在所测试的所有浓度下均具有显著性（P<0.01）。利多卡因仅影响对维拉帕米敏感的那部分钠内流，而普鲁卡因胺除此之外还抑制对维拉帕米不敏感的内流。此外，两种药物均使细胞的自发收缩频率随之降低。在同时存在普鲁卡因胺和利多卡因的情况下，发现对维拉帕米敏感的钠内流与收缩频率之间存在密切的线性相关性（r = 0.99）。由此以及先前表明收缩频率依赖于内向维拉帕米敏感钠内流的研究，提示这些药物通过对膜钠交换的主要影响来改变该制剂的自律性。
