目的　观察左旋精氨酸相关肽 (L -ArgX)对大鼠血小板聚集、血栓形成及血浆一氧化氮 (NO)、环磷酸鸟苷 (cGMP)和前列环素 (PGI2 )的影响。方法　 2 4只SD雄性大鼠随机分为 2组 ,分别灌服L -ArgX 6 1 4mg/kg·b w及对同体积空白对照液 ,每日 1次 ,共 8d。 8d后观察大鼠血小板聚集 (比浊法 )、血栓形成 (丝线法 )及血浆NO、cGMP、PGI2 浓度的变化 (分光光度法和放免法 )。结果L -ArgX可显著抑制大鼠血小板聚集率及血栓形成 ,使血浆NO、cGMP浓度升高 ,血浆PGI2 浓度有升高趋势 ,但与对照组相比无统计学差异。结论L -ArgX可抑制血小板聚集 ,其作用机制可能由一氧化氮 -环磷酸鸟苷代谢通路(NO -cGMPpathway)所介导 ,此外尚可能有其它作用机制参与。L -ArgX可视为一种NO前体 ,具有抗凝血作用。 Objective To observe the effects of L-arginine-related peptide (L-ArgX) on platelet aggregation, thrombosis and plasma levels of nitric oxide (NO), cGMP and PGI2 in rats. Methods 24 male Sprague-Dawley rats were randomly divided into 2 groups: L -ArgX 6 1 4mg / kg · bw and blank control solution at the same volume once daily for 8 days. After 8 days, the changes of platelet aggregation (turbidimetry), thrombus formation (thread method) and plasma concentrations of NO, cGMP and PGI2 were observed (spectrophotometry and radioimmunoassay). Results L-ArgX could significantly inhibit the platelet aggregation rate and thrombosis in rats, increase the concentration of plasma NO and cGMP, and increase the concentration of PGI2 in plasma, but there was no significant difference compared with the control group. Conclusion L-ArgX can inhibit platelet aggregation and its mechanism may be mediated by nitric oxide-cGMPpathway. In addition, other mechanisms of action may be involved. L-ArgX can be regarded as a NO precursor, with anti-clotting effect.