Modulation of receptor-dependent increase of calcium ions in human platelets by taurine

Taurine (2-aminoethanesulfonic acid, CAS 107-35-7) is present in high concentrations in platelets. It suppresses bronchial responses to platelet-activating factor (PAF) and inhibits aggregation induced by ADP. In the present experiments human platelet calcium responses to PAF were measured by a fluorescent label "Quin-2" method. Preincubation with 0.01 mol/l of taurine decreased effects of PAF by 250 nmol/l if the initial Ca intracellular response (delta Ca2+) to inductor was more than 400 nmol/l. If the initial response to inductor was less than 150 nmol/l, taurine did not affect the response to inductor if PAF effect was in delta Ca2+ range of 150-400 nmol/l. Hence, some effects of taurine may be ascribed to its modulating influence on secondary Ca2+ messenger.