1987 年 18 巻 3 号 p. 250-253
The purpose of the present study is to clarify the inhibitory mechanism of taurine on platelet aggregation in myocardial infarction. In vitro, platelet aggregations induced by 4.6μM ADP and calcium ionophore in the dose range of 1.7 to 10.0μM A23187 were measured by Born's method with and without 10mM taurine in normal subjects and in cases with old myocardial infarction. Platelet malondialdehyde formation induced by 125μM arachidonic acid was measured by TBA method. In order to estimate the effect of taurine on the change of cytoplasmic Ca2+ in platelet activated by 0.4U/ml thrombin, the intensity of quin 2 fluorescence was measured by Rink's method with and without 10mM taurine.
Platelet aggregations induced by 4.6μM ADP and by 2.5 and 5.0μM 23187 were significantly inhibited with 10mM taurine in cases with old myocardial infarction, and also the increase of cytoplasmic Ca2+ in platelet activated by thrombin was significant. In normal subjects, on the other hand, taurine did not inhibit them. In both of cases with old myocardial infarction and normal subjects, platelet malondialdehyde formation was not significantly affected by incubation with 10mM taurine. These results suggest that the inhibitory mechanism of taurine on platelet aggregation is not due to the effect of taurine on arachidonic metabolism, but the inhibition of cytoplasmic Ca2+ change in platelets of the cases with old myocardial infarction.