Elevation of pHi is not an essential step in calcium mobilisation in fura‐2‐loaded human platelets

FEBS Letters

Rink, T.J.¹  Simpson, A.W.M.¹ 

[1] Smith Kline and French Research Ltd, The Frythe, Welwyn AL6 9AR, England

关键词: Platelet;    pHi;    Ca2+;    Fura-2;    BCECF;   

DOI  :  10.1016/0014-5793(87)80208-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Human platelets were co-loaded with the fluorescent indicators BCECF and fura-2 to mesure pH_i and [Ca²⁺]_i and incubated with aspirin to block cyclooxygenase. Either pH_i and shape change and aggregation or pH_i and [Ca²⁺]_i were measured simultaneously in the same stirred cuvette, at 37°C. In Hepes-buffered saline containing 1 mM Ca²⁺, mean resting pH_i was 6.98±0.01 (SE, n = 59). Changes of pH_i up to ±0.35 units, imposed by additions of NH₄Cl, CO₂ or nigericin, produced no shape change or aggregation and only insignificant changes in [Ca²⁺]_i. Sufficient thrombin to raise [Ca²⁺]_i over 1 μM and cause rapid shape change and aggregation increased pH_i by no more than 0.05 units, and the increase in pH_i lagged behind the elevation of [Ca²⁺]_i. We conclude that changes in pH_i do not form a necessary or sufficient component of the pathways leading to receptor-mediated Ca²⁺ mobilisation or the stimulation of shape change or aggregation.

【 授权许可】

Unknown