Gukovskaia A S, Zinchenko V P, Mantsygin Iu A
Ukr Biokhim Zh (1978). 1987 May-Jun;59(3):39-42.
The effect of SH-reagents on cytoplasmic free Ca2+ concentration [( Ca2+]i) in rat thymocytes and B lymphoma Raji cells has been studied by means of fluorescent Ca2+ indicator quin-2. N-ethylmaleimide and ethylmercurythiosalicylate have been found to induce a dose-dependent increase of Ca2+ concentration from about 100 nM in the control cells up to 1000 nM. The effect is weakened with a decrease of the external Ca2+ concentration and is not observed already with Ca2+ concentration in the medium less than 0.2 mM. Reduction of the level of intracellular ATP does not suppress the Ca2+ response to SH-reagents. The effect of SH-reagents is weakened with a decrease of the temperature from 37 to 24 degrees C. Addition of 1 mM Mn2+ or Ca2+ into the standard medium containing 1 mM CaCl2 prevents Ca2+ concentration increase in the cytoplasm under the action of SH-reagents. The conclusion is made that in lymphocytes Ca2+ permeability is regulated by a protein(s) sensitive to the SH-reagent and that a high level of SH-group oxidation is necessary to maintain the low Ca2+ permeability of lymphocyte plasma membrane. Mechanisms of SH-reagents action on the Ca2+ level in the cell are discussed.
利用荧光钙指示剂喹啉-2研究了巯基试剂对大鼠胸腺细胞和B淋巴瘤Raji细胞胞质游离钙离子浓度[Ca2+]i的影响。已发现N-乙基马来酰亚胺和硫柳汞乙酯可诱导钙离子浓度呈剂量依赖性增加，从对照细胞中的约100 nM增加至1000 nM。随着细胞外钙离子浓度降低，该效应减弱，当培养基中钙离子浓度低于0.2 mM时则未观察到该效应。细胞内ATP水平降低并不会抑制钙离子对巯基试剂的反应。随着温度从37℃降至24℃，巯基试剂的效应减弱。在含有1 mM氯化钙的标准培养基中添加1 mM锰离子或钙离子可防止在巯基试剂作用下细胞质中钙离子浓度升高。得出的结论是，在淋巴细胞中，钙离子通透性由对巯基试剂敏感的一种或多种蛋白质调节，并且高水平的巯基氧化对于维持淋巴细胞质膜的低钙离子通透性是必要的。讨论了巯基试剂对细胞内钙离子水平的作用机制。
