目的通过观察同型半胱氨酸（Ｈｃｙ）对血小板Ｌ精氨酸（ＬＡｒｇ）／一氧化氮（ＮＯ）系统的影响，探讨Ｈｃｙ对血小板损伤的机制。方法健康成人６例，平均年龄（３３±７）岁。晨取静脉血，将每例血样分为对照组及加Ｈｃｙ组，分别测定血小板ＬＡｒｇ转运功能；同时将上述两组分别设立加乙酰胆碱（Ａｃｈ）与不加Ａｃｈ组，测定血小板ＮＯ合酶（ＮＯＳ）活性、ＮＯ生成量和ｃＧＭＰ含量。结果（１）在不同浓度的Ｌ－Ａｒｇ时，Ｈｃｙ组ＬＡｒｇ转运速率均低于对照组（Ｐ＜００１）。（２）在Ａｃｈ刺激下，ＮＯＳ活性明显提高，但Ｈｃｙ组提高的程度明显低于对照组（Ｐ＜００１）。（３）在Ａｃｈ刺激下，ＮＯ生成及ｃＧＭＰ含量明显提高（Ｐ＜００１），但Ｈｃｙ组仍明显低于对照组（Ｐ＜００５）。结论Ｈｃｙ影响血小板功能可能与ＬＡｒｇ／ＮＯ系统改变有关。 Objective To investigate the mechanism of Hcy on platelet damage by observing the effect of homocysteine ​​(Hcy) on LArg / NO system. Methods Six healthy adults, mean age (33 ± 7) years old. Morning blood samples were taken, and blood samples were divided into control group and Hcy group, and L-Arg platelet function was measured respectively. At the same time, two groups were added with Ach and Ach group respectively to measure platelet NO synthase (NOS) activity, NO production and cGMP content. Results (1) At different concentrations of L-Arg, L-Arg transport rate in Hcy group was lower than that in control group (P <001). (2) Under the stimulation of Ach, the activity of NOS increased obviously, but the level of Hcy increased obviously (P <001). (3) Under the stimulation of Ach, NO production and cGMP content increased significantly (P <001), but the Hcy group was still significantly lower than the control group (P <005). Conclusion The influence of Hcy on platelet function may be related to the change of LArg / NO system.