Kukreja R C, Wei E P, Kontos H A, Bates J N
Department of Medicine, Medical College of Virginia, Richmond 23298.
Stroke. 1993 Dec;24(12):2010-4; discussion 2014-5. doi: 10.1161/01.str.24.12.2010.
The predominant view is that the endothelium-derived relaxing factor generated by acetylcholine from blood vessels is nitric oxide. However, there is evidence suggesting that certain nitric oxide-containing compounds such as nitrosothiols resemble the endothelium-derived relaxing factor generated by acetylcholine more closely than does nitric oxide itself. Accordingly, we compared the effects of nitric oxide and S-nitroso-L-cysteine on cerebral arteriolar caliber in relation to the associated increments in nitrite concentration in the effluent.
Acetylcholine, nitric oxide, and S-nitroso-L-cysteine were administered by continuous superfusion in oxygen-free solution through the space under a cranial window in anesthetized cats. Nitrite concentration was measured in the effluent. The degree of vasodilation induced was evaluated in relation to the increment in nitrite concentration.
All agents induced dose-dependent vasodilation and dose-dependent increments in nitrite concentration in the effluent. For any given degree of vasodilation, the increments in nitrite concentration were equivalent during acetylcholine or S-nitroso-L-cysteine infusion, whereas the nitrite concentrations were 10 times higher during nitric oxide infusion. After administration of nitroarginine, a competitive inhibitor of nitric oxide synthesis from arginine, there was depression in the vasodilation as well as the increment in nitrite concentration induced by acetylcholine.
S-Nitroso-L-cysteine resembles endothelium-derived relaxing factor from acetylcholine more closely than does nitric oxide.
主流观点认为，血管中乙酰胆碱产生的内皮源性舒张因子是一氧化氮。然而，有证据表明，某些含一氧化氮的化合物，如亚硝基硫醇，比一氧化氮本身更类似于乙酰胆碱产生的内皮源性舒张因子。因此，我们比较了一氧化氮和S-亚硝基-L-半胱氨酸对脑动脉口径的影响以及流出液中亚硝酸盐浓度的相应增加。
在麻醉猫的颅窗下间隙，通过在无氧溶液中持续灌注乙酰胆碱、一氧化氮和S-亚硝基-L-半胱氨酸。测量流出液中的亚硝酸盐浓度。根据亚硝酸盐浓度的增加评估诱导的血管舒张程度。
所有药物均诱导剂量依赖性血管舒张和流出液中亚硝酸盐浓度的剂量依赖性增加。对于任何给定程度的血管舒张，乙酰胆碱或S-亚硝基-L-半胱氨酸输注期间亚硝酸盐浓度的增加是等效的，而一氧化氮输注期间亚硝酸盐浓度高10倍。给予硝基精氨酸（一种从精氨酸合成一氧化氮的竞争性抑制剂）后，乙酰胆碱诱导的血管舒张以及亚硝酸盐浓度的增加均受到抑制。
S-亚硝基-L-半胱氨酸比一氧化氮更类似于乙酰胆碱产生的内皮源性舒张因子。
