摘要
目的:研究MK-447对家兔凝血酶诱导的血小板聚集释放反应及单细胞内钙水平的影响.方法:利用浊度法及测定PRP中ATP的含量评价聚集和释放反应,以荧光图像法分析细胞内钙浓度.结果:MK-447仅使兔多血小板血浆(PRP)透光度降低(DLT),即血小板变形,单血小板[Ca^(2+)]_i轻度增加(160 nmol·L^(-1)),并不被依他酸3 mmol·L^(-1)抑制.MK-447消除凝血酶诱导的DLT,聚集和ATP释放增强,呈剂量依赖性,且凝血酶介导的[Ca2+]_i由369 ±45 nmol·L^(-1)增加到621±121 nmol·L^(-1).结论:MK-447的血小板变形与其[Ca^(2+)]_i释放有关.MK-447增强凝血酶的血小板聚集和ATP释放.MK-447的这一作用可能于[Ca2+]_i的协同作用有关.
AIM: To study the effects of MK-447 on aggregation release reaction and intracellular calcium mobilizartion by thrombin. METHODS: Aggregation and release reaction were assessed by light transmission and ATP content in rabbit citrate platelet-rich plasma (PRP) , and cytosolic-free calcium was measured by fluorescence and imaging. RESULTS: MK-447 (2-aminomethyl-4-t-butyl-6-iodophenol hydrochloride) induced a decrease in light transmission (DLT), so called platelet shape change, without detectable aggregation and secretion of ATP, and increased intracellular calcium concentration ([Ca2±]i) slightly in washed single platelet loaded with Fura 2, the peak value being about 160 nmol .L-1. These effects were not inhibited by egtazic acid 3 mmol·L-1 or indometacin 3 μmol·L-1. The pretreatment of PRP with MK-447 700 umol.L-1 reduced the DLT by thrombin, potentiated and enhanced throm-bin-induced aggregation and secretion of ATP in a concentration-dependent manner. Throm-bin-induced[Ca2±]i mobilization (peak value: 369±45 nmol·L-1) was further enhanced by the administration of MK-447 at 2 min before the addition of thrombin, and the peak value reached 623 ± 121 nmol . L^1 (P < 0. 01 ). CONCLUSION:MK-447-induced plateletshape change was involved in intracellular calcium release in this preparation. MK-447 enhanced thrombin-induced aggregation and release reaction and these effects of MK-447 on aggregation and release reaction by thrombin might result from the synergistic effect of intracellular calcium mobilization.
出处
《中国药理学报》
CSCD
1995年第2期108-113,共6页
Acta Pharmacologica Sinica
