Lee K S, Tsien R W
Nature. 1983 Apr 28;302(5911):790-4. doi: 10.1038/302790a0.
Organic inhibitors of calcium influx prevent outward as well as inward current through cardiac calcium channels but do not slow current activation. Although block is antagonized by raising external calcium or barium concentrations, the competitive effect of permeant cations does not occur at the same cation binding site at which inorganic blockers act. Organic drugs show varying degrees of use-dependent block, due in part to blockade of open channels. Nitrendipine blockade of calcium currents requires doses greater than 100-fold higher than expected from radioligand binding to isolated membranes.
钙内流的有机抑制剂可阻止心脏钙通道的外向电流和内向电流，但不会减缓电流激活。尽管通过提高细胞外钙或钡的浓度可拮抗这种阻断作用，但通透阳离子的竞争效应并非发生在无机阻滞剂作用的同一阳离子结合位点。有机药物表现出不同程度的使用依赖性阻断，部分原因是对开放通道的阻断。硝苯地平对钙电流的阻断所需剂量比根据放射性配体与分离膜结合预期的剂量高出100倍以上。
