金环蛇毒组份Ⅺ兔血小板聚集功能的影响

本文采用CM-Sephadex C-50柱层析分离金环蛇原毒,得16个峰,其中组份Ⅰ有促进兔血小板聚集的作用,其聚集曲线呈两个聚集波,原毒及组份Ⅶ～ⅩⅣ对ADP诱导的血小板聚集有抑制作用,其中组份Ⅺ经DEAE-Sephadex A-50柱层析纯化,经聚丙烯酰胺圆盘电泳鉴定为单一区带,组份Ⅺ可使小鸡颈二腹肌产生挛缩,且抑制离体蛙心收缩,该组份没有ADP酶及5′-核苷酸酶活力,但有磷脂酶A_2活力,原毒及组份Ⅺ的LD_(50)(小鼠ip)分别为1.5±s 0.2及8.0±s 1.3 mg·kg~(-1)(95％可信限),组份Ⅺ不引起富血小板血浆中乳酸脱氢酶含量升高,对ADP,花生四烯酸,A23187及凝血酶诱导的血小板聚集均有抑制作用,其IC_(50)分别为:68.8,10.0,10.1,6.3μg·ml~(-1),但对血小板5羟色胺的释放无明显影响,其作用机理需进一步研究。

Effect of fraction XI from Bungarusfasciatus venom on rabbit platelet aggregation

The venom of Bungarus fasciatus has been separated by chromatography into sixteen fractions. Among them, fraction I possessed the platelet aggregation-inducing activity. The crude venom of Bungarus fasciatus and fraction Ⅶ-ⅩⅣ possessed an inhibitory activity on platelet aggregation induced by ADP. Fraction Ⅺ which possessed an inhibitory activity was refracted. It inhibited the contraction of the isolated frog heart and produced contracture in the isolated chick biventer cervicis preparation. LD50 of fraction Ⅺ and crude venom was 8.0± s 1.3 and 1.46± s 0.24 (95% confidence limit) mg·kg-1 (ip) respectively. Fraction XI was devoid of ADPase and 5′-nucleotidase activities. It possessed the phos-pholipase A2 activity. No lactate dehydrogenase was released. In rabbit platelet-rich plasma, fraction Ⅺ inhibited the platelet aggregations induced by ADP, arachidonic acid, ionophore A23187 and thrombin and the inhibition was dose-dependent, with IC50 of 68.8, 10.0, 10.1, 6.3 μg·ml-1, respectively. The serotonin release was unaffected.