一氧化氮的生物学活性及其在肝脏损伤中的作用

一氧化氮（Ｎｉｔｒｉｃ ｏｘｉｄｅ，ＮＯ）是一种难溶于水的脂溶性气体。它在体内扮演着生理和病理的双重角色。小剂量ＮＯ有着重要的信息传递作用。在神经系统中具有类似神经递质的信息传递功能，在免疫系统中具有杀灭肿瘤细胞、细菌、寄考虫和病毒的作用；在心血管系统中具有扩张血管，抑制血小板聚集与粘附，调节血流和血压的功能，但大剂量ＮＯ，又可产生细胞毒笥，导致组织细胞损伤，是肝组织损伤的重要介导因子。

Nitric Oxide:Biological Activity and Damage to Liver

Nitric oxide (NO),a water insoluble and fat soluble gas,is synthesized from the amino L arginine by the NO synthase.NO might exert both of physiological and pathological effects depending on its oxidation reduction status and amounts.NO can play an important role in respiration,digestion,cardiovascular system,immune system and nervous system.For example,a little NO can play a message transmission role like neurotansmitters in the central and peripheral nervous system.It has many functions in immune such as killing tumor cell,bacterial ,Virus and parasite.NO has other biological effects including vasodilation,blood pressure and flow regulation,platelet inhibition. A lot of NO may be an important mediator of liver immunity damage.