Packham M A, Bryant N L, Guccione M A
Department of Biochemistry, University of Toronto, Canada.
Thromb Haemost. 1990 Apr 12;63(2):282-5.
The specific thrombin inhibitor D-phenylalanyl-L-prolyl-L-arginyl chloromethyl ketone (FPRCH2Cl, PPACK) has been used as an anticoagulant with human blood to permit the preparation of platelet-rich plasma in which the physiological concentration of Ca2+ is maintained. When we attempted to use FPRCH2Cl (40 microM) as an anticoagulant for rabbit blood, clotting was prevented for at least 6 h at room temperature, but nearly all the platelets agglutinated. Thromboxane B2 was not formed and indomethacin and prostaglandin E1 were not inhibitory. The presence of citrate delayed this agglutination, but only EDTA (not EGTA) prevented it, indicating a dependence on Mg2+. Addition of FPRCH2Cl to suspensions of rabbit platelets in Tyrode-albumin solution had no effect on responses to ADP or collagen, but completely blocked all responses to human or rabbit thrombin. Thus plasma is required for the agglutination. Intravenous injection of FPRCH2Cl (5 mg/3 kg rabbit) reduced the platelet count to less than 50% by 15 to 25 min. Thus FPRCH2Cl cannot be used as an anticoagulant for rabbit blood when platelets are to be examined, and has a profound effect on the platelet count in vivo in rabbits. These effects should be considered when FPRCH2Cl is used as an antithrombotic agent for in vivo experiments with rabbits.
特异性凝血酶抑制剂D-苯丙氨酰-L-脯氨酰-L-精氨酰氯甲基酮（FPRCH2Cl，PPACK）已被用作人血抗凝剂，以制备可维持Ca2+生理浓度的富血小板血浆。当我们试图用FPRCH2Cl（40 microM）作为兔血抗凝剂时，在室温下凝血被阻止至少6小时，但几乎所有血小板都发生了凝集。血栓素B2未形成，吲哚美辛和前列腺素E1无抑制作用。柠檬酸盐的存在延迟了这种凝集，但只有EDTA（而非EGTA）可阻止凝集，表明其依赖Mg2+。向兔血小板在Tyrode-白蛋白溶液中的悬液中添加FPRCH2Cl对ADP或胶原的反应无影响，但完全阻断了对人或兔凝血酶的所有反应。因此凝集需要血浆。静脉注射FPRCH2Cl（5 mg/3 kg兔）在15至25分钟内使血小板计数降至50%以下。因此，当要检测血小板时，FPRCH2Cl不能用作兔血抗凝剂，并且对兔体内血小板计数有深远影响。在将FPRCH2Cl用作兔体内实验的抗血栓形成剂时，应考虑这些影响。
