Effect of cyclosporin A and ionophores on the intracellular pH of lymphocytes as measured by flow cytometry.
Because of the known importance of pHi changes on the biology of cells, we have investigated the effect of CsA, the clinically important immunomodulator, on the pHi of resting mouse spleen and human peripheral blood lymphocytes. We have found that pharmacological doses (0.8 microM) of CsA caused no change in the pHi in these cells. Similarly, the Ca2+ ionophore, A23187, up to 5 microns concentration, had no effect on the pHi of these cells, in contrast to previous reports. However, higher doses of CsA (2.4-8.0 microM) did change the pHi transiently or permanently. These results were obtained with flow cytometric measurements of fluorescence intensity of the pH-sensitive dye, BCECF.
Tron
L
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Division of Research and Testing, Food and Drug Administration, Washington, DC 20204.
Siegel
J P
JP
Aszalos
A
A
D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D003524:Cyclosporins / Q000494:pharmacology*; D005434:Flow Cytometry; D006863:Hydrogen-Ion Concentration; D007476:Ionophores; D008214:Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL
D003524:Cyclosporins; D007476:Ionophores; D000001:Calcimycin