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Arachidonic acid inhibits capacitative Ca2+ entry and activates non-capacitative Ca2+ entry in cultured astrocytes |
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| Authors: | Yang Kun-Ta Chen Wen-Pin Chang Wei-Luen Su Ming-Jai Tsai Ke-Li |
| Institution: | a Institute of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan b Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan c Graduate Institute of Physiology and Molecular Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan |
| Abstract: | Arachidonic acid (AA) plays important physiological or pathophysiological roles. Here, we show in cultured rat astrocytes that: (i) endothelin-1 or thapsigargin (Tg) induces store-depleted activated Ca2+ entry (CCE), which is inhibited by 2-aminoethoxydiphenyl borane (2-APB) or La3+; (ii) AA (10 μM) and other unsaturated fatty acids (8,11,14-eicosatrienoic acid and γ-linoleic acid) have an initial inhibitory effect on the CCE, due to AA- or fatty acid-induced internal acid load; (iii) after full activation of CCE, AA induces a further Ca2+ influx, which is not inhibited by 2-APB or La3+, indicating that AA activates a second Ca2+ entry pathway, which coexists with CCE; and (iv) Tg or AA activates two independent and co-existing non-selective cation channels and the Tg-induced currents are initially inhibited by addition of AA or weak acids. A possible pathophysiological effect of the AA-induced Ca]i overload is to cause delayed cell death in astrocytes. |
| Keywords: | AA Ca2+ CCE Non-CCE |
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