Rat platelets are deficient in internal Ca2+ release and require influx of extracellular Ca2+ for activation

FEBS Letters

Feijge, Marion A.H.¹  Heemskerk, Johan W.M.¹  Hornstra, Gerard¹  Rietman, Ellen¹ 

[1] Departments of Biochemistry and Human Biology, Biomedical Center, University of Limburg, P.O. Box 616, 6200 MD Maastricht, The Netherlands

关键词: ADP;    Calcium channel;    Fura-2;    Platelet;    Thrombin;    (Rat);   

DOI  :  10.1016/0014-5793(91)80690-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Calcium fluxes were studied in fura-2-labeled rat platelets. Thrombin, ADP and ionomycin induced rapid mobilization of internally stored Ca²⁺, which resulted in only a moderate increase of cytosolic [Ca²⁺]_i. Thrombin and ADP stimulated influx of extracellular Ca²⁺, which was monitored as uptake of ⁴⁵Ca²⁺ and of Mn²⁺. With either agonist, the influx of Ca²⁺ magnified the initial increase of [Ca²⁺]_i. Since responses of rat platelets were dependent on external [Ca²⁺], we conclude that Ca²⁺ influx complements the mobilization of internal stores to reach sufficiently high [Ca²⁺]_i for full activation. A regulatory effect of protein kinase C modulators was observed on both agonist-induced elevation of [Ca²⁺]_i and receptor-mediated Ca²⁺ entry.

【 授权许可】

Unknown