Enhancement of collagen‐induced phosphoinositide turnover by thromboxane A2 analogue through Ca2+ mobilization in human platelets

FEBS Letters

Takai, Yoshimi¹  Tanimoto, Tetsuji¹  Tsuda, Terutaka¹  Kikuchi, Akira¹  Kaibuchi, Kozo¹ 

[1] Department of Biochemistry, Kobe University School of Medicine, Kobe 650, Japan

关键词: Platelet;    Collagen;    Thromboxane;    Phosphoinositide;    Ca2+;    Protein phosphorylation;    PG;    prostaglandin;    TX;    thromboxane;    STA2;    9;    11-epithio-11;    12-methanothromboxane A2;    MLC;    myosin light chain;    PA;    phosphatidic acid;    IP3;    inositol 1;    4;    5-trisphosphate;   

DOI  :  10.1016/0014-5793(85)80052-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

In human washed platelets, collagen-induced phosphoinositide turnover was inhibited by indomethacin, an inhibitor of thromboxane A₂ (TXA₂) formation, particularly at lower doses of collagen. This inhibition was counteracted by the addition of 9,11-epithio-11,12-methano-TXA₂ (STA₂), a stable analogue of TXA₂ as well as by the Ca²⁺ ionophore A23187. STA₂ and A23187 did not stimulate phosphoinositide turnover markedly, but significantly increased cytoplasmic free Ca²⁺ concentrations. The actions of STA₂ were blocked by 13-azaprostanoic acid, a TXA₂ receptor antagonist. These results suggest that TXA₂ is generated during the action of collagen and increases cytoplasmic free Ca²⁺ which then stimulates phosphoinositide turnover in cooperation with collagen.

【 授权许可】

Unknown