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Membrane depolarization inhibits thrombin‐induced calcium influx and aggregation in human platelets
Author(s) -
Kovács Tünde,
Tordai A.,
Szász Ilma,
Sarkadi B.,
Gárdos G.
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)81532-s
Subject(s) - calcium , depolarization , thrombin , chemistry , biophysics , calcium in biology , intracellular , platelet , membrane , ionophore , biochemistry , medicine , biology , organic chemistry
The relationship between thrombin‐evoked changes in intracellular calcium concentration ([Ca 2+ ] i ) and aggregation was examined in Indo‐1‐loaded human platelets. The stimulus‐induced intracellular calcium release and external calcium influx, as well as platelet aggregation, were studied in the same cell preparation. A close correlation between the sustained high [Ca 2+ ] i level, depending on calcium entry, and the aggregation response was found. Gramicidin, at a concentration high enough to induce membrane depolarization, strongly inhibited the calcium influx and aggregation, but did not influence the thrombin‐induced intracellular calcium release. We conclude that calcium influx through depolarization‐inhibited calcium channels is a prerequisite of thrombin‐induced platelet aggregation.