Kovács T, Szász I, Sarkadi B, Brezanóczy F, Gárdos G
National Institute of Haematology and Blood Transfusion, Hungary.
Acta Biochim Biophys Hung. 1989;24(1-2):83-99.
Human neutrophil granulocytes, when placed into hypoosmotic media, first swell, than show a regulatory volume decrease (RVD) reaction. This RVD is the most effective at pH 7.5 when inosine is used as a metabolic substrate. The RVD reaction is blocked by the inhibitors of the calcium-induced K+ transport, such as quinine, quinidine, trifluoperazine (TFP), as well as by those of the conductive Cl-transport (dipyridamole, SITS, oligomycin C). Removal of external calcium by EGTA, or addition of the calcium channel inhibitor, verapamil, reduce the RVD. Ouabain affects RVD only after long preincubation and furosemide or phloretin have hardly any effect on this process. In a hypoosmotic KCl medium neutrophils show a TFP-, and SITS-sensitive secondary volume increase. All these data indicate the opening of Ca2+-induced K+ channels and of conductive Cl- channels in hypoosmotically shocked neutrophils. Under these conditions, however, direct measurement of cytoplasmic calcium by Indo-1 does not show any major change in the overall cytoplasmic free Ca2+ levels. In neutrophils, the reduced calcium signal evoked by formyl-methionyl-leucyl-phenylalanine (fMLP) after a hypoosmotic shock, suggests that cellular calcium metabolism is altered under these conditions.
人中性粒细胞置于低渗介质中时，首先会肿胀，然后呈现调节性容积减小（RVD）反应。当肌苷用作代谢底物时，这种RVD在pH 7.5时最为有效。RVD反应可被钙诱导的钾转运抑制剂（如奎宁、奎尼丁、三氟拉嗪（TFP））以及传导性氯转运抑制剂（双嘧达莫、SITS、寡霉素C）阻断。用乙二醇双四乙酸（EGTA）去除细胞外钙，或添加钙通道抑制剂维拉帕米，会降低RVD。哇巴因只有在长时间预孵育后才会影响RVD，而速尿或根皮素对这一过程几乎没有影响。在低渗氯化钾培养基中，中性粒细胞表现出对TFP和SITS敏感的继发性容积增加。所有这些数据表明，在低渗休克的中性粒细胞中，钙诱导的钾通道和传导性氯通道开放。然而，在这些条件下，用 Indo-1 直接测量细胞质钙并未显示细胞质游离钙总体水平有任何重大变化。在中性粒细胞中，低渗休克后甲酰甲硫氨酰亮氨酰苯丙氨酸（fMLP）诱发的钙信号减弱，表明在这些条件下细胞钙代谢发生了改变。
