腺苷二磷酸在凝血酶信号传递过程中的作用

Role of adenosine diphoasphatase in the course of thrombin signal transmission

目的比较腺苷二磷酸(ADP)在两类凝血酶受体活化过程中对血小板聚集率以及血小板膜表面活化标记物表达的影响,探讨ADP在凝血酶信号传递机制中的作用。方法分别以凝血酶受体(PAR)活化肽PAR1-AP与PAR4-AP诱导血小板活化,观测腺苷三磷酸双磷酸酶(Apyrase,ADP抑制剂)VⅡ作用过程中血小板聚集以及血小板膜表面糖蛋白(GP)Ib与P-选择素的改变。结果两类凝血酶受体都能诱导血小板活化,产生完全的聚集波,血小板膜GPIb则呈现先进行性减少后逐渐回升的可逆性变化,P-选择素水平持续升高。ApyraseVⅡ作用后,PAR1-AP诱导的血小板聚集反应受到部分抑制,而PAR4-AP诱导的血小板聚集反应未有明显改变。ApyraseVⅡ加速PAR1途径GPIb回复细胞表面,对PAR4途径中GPIb的改变则没有显著影响。两种活化途径中P-选择素的表达都不受ApyraseVⅡ的影响。结论ADP在凝血酶信号传递过程中发挥重要作用,其中PAR1途径与ADP参与密切相关。

Objective To study the effects of adenosine diphoasphatase （ADP） on platelet aggregation and expression of glycoprotein （GP） on the surface of platelet membrane after activation of thrombin receptors, so as to investigate its role in thrombin signal transmission. Methods Perpheral blood samples were collected from from 10 healthy volunteers. Platelets were extracted. The thrombin receptor activating peptides （TRAP）, protease-activated receptor 1 activated peptide （PAR1-AP, SFLLRN, 25 μmoL/L） and PAR4-AP （ AYPGKF, 250 μmoL/L） were added into the suspension of platelets respectively to induce platelet aggregation. In apyrase inhibition test apyrase Ⅱ was added into the suspension of platelets for 2 hours and then PAR1 -AP or PAR4-AP was added respectively to observe the the expression of GPIb and P-selectin with flow cytometry. Results Either PAR1 and PAR4 induced platelet aggregation. After apyrase Ⅱ stimulation the PAR4-AP induced platelet aggrgation was not influenced and PAR1-AP induced platelet aggrgation was partially inhibited with a reversible aggrgation curvbe. Stimulated by PAR1-AP and PAR4-AP the GPIb decreased firstly and then gradually returned to normal. Apyrase VⅡ hae not significant influence on the GPlb expression,but accelerated the return of GPlb to the platelet surface after PAR1 stimulation so that the lowest point was accelerated to 2 min, compared to that of the control group （5 min） and there were significantly differences 10 and 30 min later between these 2 groups （ all P 〈 0. 05 ）. The P-selectin expression was remarkably increased 2 min after the PAR1-AP and PAR4-AP induction and peaked 2 min later. Apyrase VⅡ did not significantly influence the P-selectin expression in these 2 activation ways. Condusion ADP plays an important role in the thrombin signal transmission, especially in the PAR1 pathway.