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A dual effect of arachidonic acid on Ca 2+ transport systems in lymphocytes
Author(s) -
Khodorova A.B.,
Astashkin E.I.
Publication year - 1994
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(94)01029-3
Subject(s) - chemistry , divalent , arachidonic acid , permeability (electromagnetism) , biophysics , calcium , intracellular , membrane , quenching (fluorescence) , membrane transport , membrane permeability , fluorescence , nuclear chemistry , biochemistry , biology , physics , organic chemistry , quantum mechanics , enzyme
A sustained increase of cytoplasmic Ca 2+ concentration ([Ca 2+ ] i ) in lymphocytes was induced by a potent inhibitor of the intracellular Ca 2+ ‐pump 2,5‐di‐(tert‐butyl)‐1,4‐hydroquinone (BHQ) that effectively depletes Ca 2+ stores and produces Ca 2+ influx. The addition of low concentrations of arachidonic acid (AA) (less than 10 μM) in the presence of a BHQ‐induced Ca 2+ response produced a [Ca 2+ ] i decrease. At the same time at higher concentrations, AA induced an additional increase of [Ca 2+ ] i . The unidirectional uptake of Mn 2+ into fura‐2 loaded thymocytes was used to examine the effects of AA and BHQ on Ca 2+ permeability of the plasma membrane. Judging by the rate of Mn 2+ ‐induced fura‐2 fluorescence quenching, AA causes a concentration‐dependent increase of the divalent cations' permeability both in the control solution and in the presence of BHQ. These results allowed us to suggest that the decrease of BHQ‐induced [Ca 2+ ] i stationary levels caused by low AA concentrations is due to the enhancement of Ca 2+ extrusion from the cell, whereas the additional [Ca 2+ ] i increase at high AA concentrations results from an elevation of cell membrane Ca 2+ permeability.