Webb George D, Lim Lay Har, Oh Vernon M S, El Oakley Reida, Lee Chuen Neng, Wong Poo Sing, Aye W Maung Maung, Chan Edwin S Y, Moore Philip K
Department of Pharmacology, National University of Singapore, Singapore.
J Thorac Cardiovasc Surg. 2006 Nov;132(5):1131-6. doi: 10.1016/j.jtcvs.2006.08.001.
Endothelial nitric oxide synthase (type III) generates nitric oxide, which dilates blood vessels. Recently, it was discovered that arterial smooth muscle cells express neuronal nitric oxide synthase (type I). The purpose of this study was to determine the relative amounts of neuronal nitric oxide synthase in the human internal thoracic artery and saphenous vein.
Remainder segments of internal thoracic arteries and saphenous veins were obtained from 45 patients during coronary artery bypass grafting. Western blotting used specific antibodies against the 3 isoforms of human nitric oxide synthase and beta-actin (for normalization) to measure the relative amounts of the 3 isoforms of nitric oxide synthase proteins in vessel specimens. Immunohistochemistry was used to localize the 3 proteins in specific cells.
Western blotting detected all 3 isoforms of nitric oxide synthase in the human internal thoracic artery. The band density (normalized to beta-actin) of neuronal nitric oxide synthase was not significantly different from the band density of endothelial nitric oxide synthase. The amounts of neuronal nitric oxide synthase in arteries and veins were equal. Immunohistochemistry showed that the highest expression of endothelial nitric oxide synthase was in endothelial cells, but some expression was also seen in smooth muscle cells. Most of the neuronal nitric oxide synthase was in smooth muscle cells. The location and relative amounts of inducible nitric oxide synthase were variable.
Neuronal nitric oxide synthase is expressed in the vascular smooth muscle of patients undergoing bypass, and the amount in the internal thoracic artery is the same as in the saphenous vein.
内皮型一氧化氮合酶（Ⅲ型）可生成一氧化氮，使血管扩张。最近发现，动脉平滑肌细胞可表达神经元型一氧化氮合酶（Ⅰ型）。本研究旨在测定人胸廓内动脉和大隐静脉中神经元型一氧化氮合酶的相对含量。
在冠状动脉搭桥手术期间，从45例患者获取胸廓内动脉和大隐静脉的剩余节段。蛋白质印迹法使用针对人一氧化氮合酶3种同工型及β-肌动蛋白（用于标准化）的特异性抗体，来测量血管标本中一氧化氮合酶3种同工型蛋白质的相对含量。免疫组织化学用于将这3种蛋白质定位到特定细胞中。
蛋白质印迹法在人胸廓内动脉中检测到了一氧化氮合酶的所有3种同工型。神经元型一氧化氮合酶的条带密度（以β-肌动蛋白标准化）与内皮型一氧化氮合酶的条带密度无显著差异。动脉和静脉中神经元型一氧化氮合酶的含量相等。免疫组织化学显示，内皮型一氧化氮合酶的最高表达在内皮细胞中，但在平滑肌细胞中也有一些表达。大部分神经元型一氧化氮合酶存在于平滑肌细胞中。诱导型一氧化氮合酶的定位和相对含量存在差异。
神经元型一氧化氮合酶在接受搭桥手术患者的血管平滑肌中表达，且胸廓内动脉中的含量与大隐静脉中的相同。
