Kasuya H, Weir B K, Nakane M, Pollock J S, Johns L, Marton L S, Stefansson K
Section of Neurosurgery, University of Chicago, Illinois.
J Neurosurg. 1995 Feb;82(2):250-5. doi: 10.3171/jns.1995.82.2.0250.
Endothelium-dependent vasodilation may be impaired during cerebral vasospasm following subarachnoid hemorrhage. Under normal circumstances nitric oxide (NO) released by endothelial cells induces relaxation of smooth muscle by activating the soluble form of guanylate cyclase within muscle cells. In this study the levels of both endothelial NO synthase, the enzyme that produces NO, and soluble guanylate cyclase were determined in canine basilar arteries in a double-hemorrhage model using Western blot immunoassays. Thirty dogs were assigned to three groups: Group D0, control; Group D2, dogs sacrificed 2 days after cisternal injection of blood; and Group D7, dogs given double cisternal injections of blood and sacrificed 7 days after the first injection. Constriction of the basilar artery was confirmed by arterial angiography. Portions of the affected arteries or the corresponding region in control animals were solubilized for sodium dodecylsulfate-polyacrylamide gel electrophoresis and Western blotting. A specific monoclonal antibody against endothelial NO synthase was used. The extract from basilar arteries showed two bands on the blots: 135 kD, characteristic of endothelial NO synthase, and 120 kD, which may be a degradation product of the enzyme. The densitometer values of the bands were presented as percentages of D0 control values. Although the total signal in the D7 group was less than that of the D0 control group (D2, 97% +/- 22%; D7, 78% +/- 40%), it was not statistically significant. The proportion of the 135-kD form decreased between Groups D0 and D7, but the difference was not significant. A single major band corresponding to the alpha-subunit of soluble guanylate cyclase was seen at 70 kD in the basilar artery extracts. The signals of D2 and D7 samples were 69% +/- 40% and 25% +/- 18%, respectively. There was a significant difference between D7 and D0 (p < 0.001). The reduced expression of soluble guanylate cyclase may be related to the impairment of endothelium-dependent vasodilation in vasospasm.
蛛网膜下腔出血后发生脑血管痉挛时，内皮依赖性血管舒张功能可能受损。在正常情况下，内皮细胞释放的一氧化氮（NO）通过激活肌细胞内可溶性鸟苷酸环化酶来诱导平滑肌舒张。在本研究中，采用蛋白质印迹免疫分析法，在双次出血模型的犬基底动脉中测定了产生NO的酶——内皮型一氧化氮合酶和可溶性鸟苷酸环化酶的水平。30只犬被分为三组：D0组，对照组；D2组，小脑延髓池注射血液后2天处死的犬；D7组，小脑延髓池两次注射血液且在首次注射后7天处死的犬。通过动脉血管造影证实基底动脉收缩。将受影响动脉的部分或对照动物的相应区域进行溶解，用于十二烷基硫酸钠-聚丙烯酰胺凝胶电泳和蛋白质印迹分析。使用针对内皮型一氧化氮合酶的特异性单克隆抗体。基底动脉提取物在印迹上显示出两条带：135 kD，为内皮型一氧化氮合酶的特征性条带；120 kD，可能是该酶的降解产物。条带的光密度计值以D0对照组值的百分比表示。虽然D7组的总信号低于D0对照组（D2组，97%±22%；D7组，78%±40%），但差异无统计学意义。D0组和D7组之间135-kD形式的比例下降，但差异不显著。在基底动脉提取物中，在70 kD处可见一条对应于可溶性鸟苷酸环化酶α亚基的主要条带。D2组和D7组样品的信号分别为69%±40%和25%±18%。D7组和D0组之间存在显著差异（p<0.001）。可溶性鸟苷酸环化酶表达降低可能与血管痉挛时内皮依赖性血管舒张功能受损有关。
