钩藤碱对家兔血小板聚集及胞浆游离钙离子浓度的影响

目的 研究钩藤碱(Rhy)对兔血小板细胞内游离钙离子浓度及血小板聚集的影响.方法 56只雄性家兔的血样随机分为正常对照组,阿司匹林0.85,1.69和2.78 mmol·L-1组,Rhy 0.33,0.65和1.30 mmol·L-1组.Born法测定血小板聚集率,双波长Fura-2荧光分光光度法测定血小板胞浆游离钙离...

Effect of rhynchophylline on platelet aggregation and cytoplasmic free calcium level in rabbits

OBJECTIVE To investigate the effect of rhynchophylline (Rhy) on rabbit cytoplasmic free calcium level and platelet aggregation, and possible mechanism. METHODS Blood samples from 56 male rabbits were randomly divided into control group (normal saline), aspirin(Asp) 0.85, 1.69 and 2.78 mmol·L^-1 groups, Rhy 0.33, 0.65 and 1.30 mmol·L^-1 groups. Platelet aggregation and cytoplasmic free calcium level were determined by Born method and double beam fluorescence spectrophotometric method, respectively. RESULTS ]Compared with platelet aggregation rate (59.6±0.6)% in control group induce by ADP 15 μmol·L^-1, platelet aggregation rates in Rhy 0.33, 0.65 and 1.30 mmol·L^-1 groups were decreased to (35.4±7.7)%, (18.2±4.8)% and (6.9±0.9)%, respectively (P<0.05). Compared with control group (80.8±1.5)%, Rhy 0.65 and 1.30 mmol·L^-1 rendered maximum platelet aggregation rate induced by thrombin 3 kU·L^-1 (42.8±3.9)% and (18.9±5.5)%(P<0.05), respectively. In presence of extracellular Ca²⁺, the comparison of cytoplasmic free calcium level (528±25)nmol·L^-1 in control group and Rhy group were performed, Rhy 0.33, 0.65 and 1.30 mmol·L^-1 depressed obviously cytoplasmic free calcium level to 418±27, 303±7 and (257±25)nmol·L^-1, respectively. In the inducement of ADP and thrombin, the cytoplasmic free calcium level in control group were 751±29 and 982±50. After Rhy 0.65 and 1.30 mmol·L^-1 administered, the cytoplasmic free calcium level induced by ADP decreased to 620±37 and (528±17)nmol·L^-1, respectively (P<0.05), the cytoplasmic free calcium level induced by thrombin decreased to 777±29 and (658 ±23)nmol·L^-1, respectively (P<0.05). In absence of extracellular Ca²⁺, Rhy was devoid of significant influence on cytoplasmic free calcium level of rabbit platelet. CONCLUSION Rhy markedly inhibited rabbit platelet aggregation induced by ADP or thrombin, it may depress the inflow of Ca²⁺ and thus depression the rise of cytoplasmic free calcium level in platelet.