普鲁卡因胺抑制凝血酶诱导的人单个血小板游离Ca~(2+)升高

用570型粘附式细胞仪动态观察普鲁卡因胺（Procainamide，Pro）对凝血酶激活的人单个血小板细胞内游离Ca2+的影响。静息状态时对照组和给药组荧光值均较低。当加入0．1u／ml凝血酶时，荧光强度迅速上升，两组达峰值时间均为20s，但给药组最大升高幅度比对照组低21％（P＜0．05）。随后荧光强度迅速下降，两组下降率均为-1u／s，对照组和给药组下降幅度分别为57％和76％（P＜0．05）。上文结果提示，普鲁卡因胺降低凝血酶诱导的血小板游离Ca2+升高，对Ca2+的再摄取没有影响。

Inhibition of procainamide on the rise of cytosolic free Ca~(2+) induced by thrombin in single fibrinogen-bound human platelets

Effect of procainamide (Pro 0. 5mmol/L) on single human platelet cytosolic free Ca2+ induced by thrombin was investigated by ACAS-570 (Adherent cell analysis and sorting cytometer). Fluo-3-loaded platelets were immobilized on a fibrinogen-coated surface. Fluorescences of fluo-3 were low in unstimulated immobilized platelets. When platelets were stimulated by thrombin (0. 1units/ml),a rapid rise of cytosolic Ca2+ was observed,and the time to peak was 20 seconds in both the control and Pro groups. The peak level of Pro group was 21% less than that of control group (P<0. 05). Subsequently,a rapid decrease was seen with a rate of -1 units/sec in both groups. The decreasing extents of control and Pro groups were 57% and 76% respectively (P<0.05),and remained at this level. These results indicate that procainamide decrease platelet free-Ca2+ induced by thrombin without affecting the rate of Ca2+ uptake.