ATP‐induced, sustained calcium signalling in cultured rat cortical astrocytes: evidence for a non‐capacitative, P2X7‐like‐mediated calcium entry

FEBS Letters

Alloisio, Susanna²  Monaldi, Ilaria²  Nobile, Mario²  Cugnoli, Carlo²  Ferroni, Stefano¹ 

[1] Department of Human and General Physiology, University of Bologna, Via San Donato, 19/2, 40127 Bologna, Italy;Institute of Biophysics, CNR, Via De Marini, 6, 16149 Genoa, Italy

关键词: Astroglia;    P2 purinoceptor;    Microfluorimetry;    Calcium influx;    P2X7 receptor;    [Ca2+]i;    free cytosolic Ca2+ concentration;    2-MeSATP;    2-methylthio-ATP;    β;    γ-meATP;    β;    γ-methylene-ATP;    Bz-ATP;    3′-O-(4-benzoyl)benzoyl-ATP;    CPA;    cyclopiazonic acid;    Sura;    suramin;    PPADS;    pyridoxalphosphate-6-azophenyl-2′;    4′-disulfonic acid;    oATP;    oxidized ATP;    CCE;    capacitative Ca2+ entry;    PLC;    phospholipase C;    IP3;    inositol triphosphate;   

DOI  :  10.1016/S0014-5793(03)00129-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The receptor mechanisms regulating the ATP-induced free cytosolic Ca²⁺ concentration ([Ca²⁺]_i) changes in cultured rat cortical type-1 astrocytes were analyzed using fura-2-based Ca²⁺ imaging microscopy. Upon prolonged ATP challenge (1–100 μM), astroglial cells displayed a biphasic [Ca²⁺]_i response consisting of an initial peak followed by a sustained elevation. Suramin and pyridoxalphosphate-6-azophenyl-2′,4′-disulfonic acid blocked both components, albeit to a different extent. By contrast, the selective P2X7 antagonist oxidized ATP irreversibly abrogated the sustained [Ca²⁺]_i signal without affecting the transient phase. Finally, astrocyte challenge with the selective P2X7 agonist 3′-O-(4-benzoyl)benzoyl-ATP evoked a sustained [Ca²⁺]_i elevation, which occluded that induced by ATP. We can conclude that in cultured cortical astrocytes the ATP-mediated sustained [Ca²⁺]_i rise does not implicate capacitative Ca²⁺ entry but involves Ca²⁺ influx through P2X7-like receptors.

【 授权许可】

Unknown