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Trifluoperazine and chlorpromazine block secretion from human platelets evoked at basal cytoplasmic free calcium by activators of C‐kinase
Author(s) -
Sanchez A.,
Hallam T.J.,
Rink T.J.
Publication year - 1983
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(83)80015-5
Subject(s) - trifluoperazine , chlorpromazine , secretion , calmodulin , protein kinase c , platelet , staurosporine , chemistry , endocrinology , calcium , medicine , ionophore , diacylglycerol kinase , microbiology and biotechnology , biochemistry , kinase , pharmacology , biology
Trifluoperazine, chlorpromazine and other drugs to inhibit calmodulin‐dependent processes are also known to inhibit protein kinase C. The effect of these agents on secretion evoked by known activators of C‐kinase has been studied in human platelets loaded with the fluorescent Ca indicator, quin2 and preincubated with aspirin. The secretory response stimulated by phorbol ester and exogenous diacyglycerol, at basal levels of cytoplasmic free Ca 2+ , [Ca 2+ ] i , was suppressed by trifluoperazine, chlorpromazine and W‐7, as was the secretion evoked by collagen that occurs without a change in [Ca 2+ ] i , The response to thrombin, which is accompanied by elevated [Ca 2+ ] i was barely affected. Modest elevation of [Ca 2+ ] i by Ca ionophore was able to overcome the inhibitory effect of these drugs on the response to phorbol ester, diacylglycerol, and collagen.