Ishida Y, Hashimoto M, Fukushima S, Masumura S, Sasaki T, Nakayama K, Tamura K, Murakami E, Isokawa S, Momose K
Mitsubishi Kasei Institute of Life Sciences, Tokyo, Japan.
J Pharmacol Toxicol Methods. 1996 Feb;35(1):19-24. doi: 10.1016/1056-8719(95)00114-x.
In order to directly detect nitric oxide (NO) liberated from isolated tissue, a practical and convenient method using a nitric oxide-sensitive electrode is described. To avoid the nonselective signal caused by ionic substances, the electrode was covered with three layers but remains permeable for gaseous substances. In a solution bubbled with 20% oxygen (pO2, approximately 150 mm Hg), administration of S-nitroso-N-acetyl-d, l-penicillamine (SNAP) at concentrations greater than 10(-7) mol/L elicited an electrode response. Based on a comparison with the chemical determination of NO released from SNAP, the electrode may be able to detect nitric oxide around nmol/L. At least 30 nmol NO per liter in anoxic conditions was reported to be detected by this electrode (Matsui, 1995). In a specially designed small chamber, the electrode was attached on the surface of endothelial side of the isolated aorta of the guinea pig. When carbachol was added to the chamber, the electrode responded when the solution was bubbled with 20% but not with 40% or 95% of oxygen, suggesting a much faster decomposition of nitric oxide in the presence of higher concentrations of oxygen. The electrode response to carbachol was abolished in the presence of NG-monomethyl-L-arginine or nitro arginine. These results suggest that the electrode method described in this manuscript is suitable for detecting nitric oxide liberated from isolated tissues when comparatively low oxygen levels are present in the physiological salt solution.
为了直接检测从离体组织释放的一氧化氮（NO），本文描述了一种使用一氧化氮敏感电极的实用且便捷的方法。为避免离子物质引起的非选择性信号，该电极覆盖有三层，但对气态物质仍具有渗透性。在通入20%氧气（pO2，约150 mmHg）的溶液中，给予浓度大于10(-7) mol/L的S-亚硝基-N-乙酰-d，l-青霉胺（SNAP）会引发电极响应。基于与化学法测定SNAP释放的NO的比较，该电极或许能够检测纳摩尔/升左右的一氧化氮。据报道，在缺氧条件下该电极能够检测到每升至少30 nmol的NO（Matsui，1995）。在一个特别设计的小室中，将电极附着在豚鼠离体主动脉内皮侧的表面。当向小室中加入卡巴胆碱时，在溶液通入20%氧气而非40%或95%氧气时电极有响应，这表明在较高浓度氧气存在时一氧化氮分解得更快。在存在NG-甲基-L-精氨酸或硝基精氨酸的情况下，电极对卡巴胆碱的响应消失。这些结果表明，本文所述的电极方法适用于在生理盐溶液中存在相对低氧水平时检测从离体组织释放的一氧化氮。
