Matlib M A
Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Ohio 45267-0575.
Ann N Y Acad Sci. 1991;639:531-42. doi: 10.1111/j.1749-6632.1991.tb17346.x.
A body of information obtained by experiments with intact tissues, isolated cells, and sarcolemmal vesicles indicates, beyond a reasonable doubt, that a specific Na(+)-Ca2+ exchange system exists in vascular smooth muscle. However, its role in the regulation of cytosolic free-Ca2+ concentration and cell tension under physiological conditions remains unclear. Under pharmacological conditions in which the Na(+)-K+ pump is inhibited either by digitalis glycosides or K(+)-free medium, Na(+)-Ca2+ exchange may be modulated by increases in cytosolic free Na+ to increase the cytosolic free-Ca2+ concentration and cell tension. Under pathological conditions in which the cytosolic Na+ concentration is increased as a result of inhibition of the Na(+)-K+ pump by endogenous ouabain or a digitalis-like factor, or activation of the Na(+)-H+ exchange or passive permeability of Na+, the Na(+)-Ca2+ exchange activity of vascular smooth muscle and the nerve terminal may play an important role in the development and/or maintenance of hypertension. These and other premises remain to be confirmed or discounted.
通过对完整组织、分离细胞和肌膜囊泡进行实验所获得的大量信息毫无疑问地表明，血管平滑肌中存在一种特定的钠钙交换系统。然而，在生理条件下其在调节胞质游离钙浓度和细胞张力方面的作用仍不清楚。在药理学条件下，洋地黄糖苷或无钾培养基抑制钠钾泵时，胞质游离钠的增加可能会调节钠钙交换，从而增加胞质游离钙浓度和细胞张力。在内源性哇巴因或类洋地黄因子抑制钠钾泵，或钠氢交换激活或钠的被动通透性增加导致胞质钠浓度升高的病理条件下，血管平滑肌和神经末梢的钠钙交换活性可能在高血压的发生和/或维持中起重要作用。这些以及其他前提仍有待证实或否定。
