Changes in free cytoplasmic magnesium following activation of human lymphocytes.
Activation of lymphocytes with 10 microM ionomycin leads to a rapid increase in the concentration of free cytoplasmic calcium ([Ca2+]i) and, at a slower rate, also to an increase in the cytoplasmic free magnesium concentration ([Mg2+]i). The ionomycin-induced Mg(2+)-mobilization response is dependent on the influx of extracellular Ca2+. After receptor-mediated lymphocyte activation, induced by mitogens or anti-receptor antibodies, a Mg(2+)-mobilization response does occur in a small fraction of the cells. Simultaneous measurement of [Ca2+]i and [Mg2+]i in individual cells showed that the receptor-triggered Mg(2+)-mobilization response is restricted to cells that have a high [Ca2+]i. It can therefore be concluded that a high [Ca2+]i induces the release into the cytoplasm of Mg2+ from intracellular stores.
Rijkers
G T
GT
Department of Immunology, University Hospital for Children and Youth, Het Wilhelmina Kinderziekenhuis, Utrecht, The Netherlands.
Griffioen
A W
AW
D002051:Burkitt Lymphoma; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism; D005434:Flow Cytometry / Q000379:methods; D005456:Fluorescent Dyes; D006801:Humans; D007211:Indoles; D015759:Ionomycin / Q000494:pharmacology; D007700:Kinetics; D008213:Lymphocyte Activation; D008274:Magnesium / Q000378:metabolism*; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D013997:Time Factors; D014407:Tumor Cells, Cultured
D005456:Fluorescent Dyes; D007211:Indoles; D015759:Ionomycin; D008274:Magnesium; C048960:indo-1; D002118:Calcium