Cyproheptadine, and pizotifen inhibit intracellular calcium elevation and Src activation in human platelets <i>in vitro</i>.

<p>(A) Human platelets were loaded with Fura-2/AM to measure intracellular [Ca2+]_i, in the presence or absence of Cyproheptadine (10 nM), pizotifen (1 nM) or EMD 281014 (40 nM) and activated with ADP (1 µM), serotonin (15 µM) or ADP and serotonin together. (B) Human platelets were incubated in the presence or absence of Cyproheptadine (10 nM), pizotifen (1 nM) or EMD 281014 (40 nM) for 5 minutes and then stimulated with ADP (1 µM), serotonin (15 µM) or ADP and serotonin together for 3 minutes, and subjected to immunoprecipitation followed by immunoblotting with anti-Src and anti-phosphotyrosine antibodies; upper panel shows quantification of the data using densitometry analysis. Each experiment was repeated at least 3 times, with blood obtained from three separate donors.