A dual effect of arachidonic acid on Ca2+ transport systems in lymphocytes

FEBS Letters

Khodorova, A.B.¹  Astashkin, E.I.¹ 

[1] Institute of Biotechnology, 8 Nauchnii Proezd, 117246 Moscow, Russian Federation

关键词: Arachidonic acid;    Ca2+;    cytosolic free;    Divalent cation transport;    Ca2+-store;    Rat thymocyte;    Human lymphocyte;    AA;    arachidonic acid;    [Ca2+]i;    cytosolic free calcium concentration;    pHi;    cytosolic H+;    BHQ;    2;    5-di-(tert-butyl)-1;    4-hydroquinone;    BSA;    bovine serum albumin;    fura-2/AM;    fura-2-acetoxymethyl ester;    DIG;    digitonin;   

DOI  :  10.1016/0014-5793(94)01029-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

A sustained increase of cytoplasmic Ca²⁺ concentration ([Ca²⁺]_i) in lymphocytes was induced by a potent inhibitor of the intracellular Ca²⁺-pump 2,5-di-(tert-butyl)-1,4-hydroquinone (BHQ) that effectively depletes Ca²⁺ stores and produces Ca²⁺ influx. The addition of low concentrations of arachidonic acid (AA) (less than 10 μM) in the presence of a BHQ-induced Ca²⁺ response produced a [Ca²⁺]_i decrease. At the same time at higher concentrations, AA induced an additional increase of [Ca²⁺]_i. The unidirectional uptake of Mn²⁺ into fura-2 loaded thymocytes was used to examine the effects of AA and BHQ on Ca²⁺ permeability of the plasma membrane. Judging by the rate of Mn²⁺-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 [Ca²⁺]_i stationary levels caused by low AA concentrations is due to the enhancement of Ca²⁺ extrusion from the cell, whereas the additional [Ca²⁺]_i increase at high AA concentrations results from an elevation of cell membrane Ca²⁺ permeability.

【 授权许可】

Unknown