Silberberg S D, Poder T C, Lacerda A E
Department of Physiology and Molecular Biophysics, Baylor College of Medicine, Houston, TX 77030.
FEBS Lett. 1989 Apr 10;247(1):68-72. doi: 10.1016/0014-5793(89)81242-6.
Endothelin (ET), a newly identified vasoconstrictor peptide produced by endothelial cells, depends on extracellular calcium for its action [(1988) Nature 332, 411-415]. It is not yet known whether the increase in calcium influx induced by ET results from a direct effect on the Ca2+ channels or is secondary to a reduction in membrane potential. To address this question, we studied the effects of ET on single-channel calcium currents of freshly dissociated porcine coronary artery smooth muscle cells using the cell-attached mode of the patch-clamp technique. We show that ET increases Ca2+-channel activity with no effect on channel open time or conductance. The ability of bath-applied ET to increase single-channel calcium currents in the cell-attached mode is evidence that the peptide acts via a second messenger system.
内皮素（ET）是一种新发现的由内皮细胞产生的血管收缩肽，其作用依赖于细胞外钙[（1988年）《自然》332卷，411 - 415页]。目前尚不清楚ET诱导的钙内流增加是由于对Ca2 +通道的直接作用，还是继发于膜电位的降低。为了解决这个问题，我们使用膜片钳技术的细胞贴附模式，研究了ET对新鲜分离的猪冠状动脉平滑肌细胞单通道钙电流的影响。我们发现ET增加了Ca2 +通道活性，而对通道开放时间或电导没有影响。在细胞贴附模式下，浴加ET增加单通道钙电流的能力证明该肽是通过第二信使系统发挥作用的。
