Csernoch L, Hunyadi J, Kovács L
Department of Physiology, University Medical School, Debrecen, Hungary.
Exp Dermatol. 2000 Jun;9(3):200-5. doi: 10.1034/j.1600-0625.2000.009003200.x.
Using isolated cells from a spontaneously immortalized human keratinocyte cell line (HaCaT) loaded with Fura-2 the regulation of intracellular Ca2+ concentration ([Ca2+]i) was studied. The continuous presence of ATP induced a biphasic response in high external Ca2+. The first component reflected the release of calcium from intracellular stores since it was present after the removal of external calcium with ethylene-glycol-bis-N,N,N',N'-tetraacetic acid (EGTA). The second phase of [Ca2+]i increase was not detectable in the absence of external calcium and raising the extracellular [Ca2+] increased the rate of rise in [Ca2+]i suggesting that it was influenced by the external environment. Furthermore, after adenosine triphosphate (ATP) had emptied the intracellular store in a calcium-free milieu, the elevation of external Ca2+ induced a secondary increase in [Ca2+]i that did not require the presence of ATP. Depleting the intracellular calcium store with a Ca-ATP-ase inhibitor (cyclopiasonic acid, 10 microM) also induced calcium entry. The depletion induced calcium entry was inhibited by econazole (100 microM). These findings indicate the presence of a calcium release activated calcium influx pathway in HaCaT keratinocytes.
使用来自自发永生化人角质形成细胞系（HaCaT）且负载了Fura-2的分离细胞，研究细胞内钙离子浓度（[Ca2+]i）的调节。在高细胞外钙离子存在的情况下，ATP的持续存在诱导了双相反应。第一成分反映了细胞内钙库中钙的释放，因为在用乙二醇双（氨基乙氧基）四乙酸（EGTA）去除细胞外钙后该成分仍然存在。在没有细胞外钙的情况下，[Ca2+]i增加的第二阶段无法检测到，而提高细胞外[Ca2+]会增加[Ca2+]i的上升速率，这表明它受细胞外环境的影响。此外，在无钙环境中三磷酸腺苷（ATP）耗尽细胞内钙库后，细胞外Ca2+的升高诱导了[Ca2+]i的二次增加，这一增加不需要ATP的存在。用钙-ATP酶抑制剂（环匹阿尼酸，10微摩尔）耗尽细胞内钙库也会诱导钙内流。这种耗尽诱导的钙内流被益康唑（100微摩尔）抑制。这些发现表明在HaCaT角质形成细胞中存在钙释放激活的钙内流途径。
