[Effect of SH-reagents on Ca2+ level in lymphocyte cytoplasm].
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.
D000634:Aminoquinolines; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D002463:Cell Membrane Permeability; D003593:Cytoplasm / Q000378:metabolism; D005033:Ethylmaleimide / Q000494:pharmacology; D005456:Fluorescent Dyes; D006801:Humans; D007700:Kinetics; D008214:Lymphocytes / Q000378:metabolism*; D010084:Oxidation-Reduction; D051381:Rats; D011919:Rats, Inbred Strains; D013439:Sulfhydryl Reagents / Q000494:pharmacology*; D013849:Thimerosal / Q000494:pharmacology
D000634:Aminoquinolines; D005456:Fluorescent Dyes; D013439:Sulfhydryl Reagents; D013849:Thimerosal; D005033:Ethylmaleimide; C035739:Quin2; D002118:Calcium
Vliianie SH-reagentov na kontsentratsiiu Ca2+ v tsitoplazme limfotsitov.