A Research for, cellular Dysfunction in Acta Stroke

硝酸甘油和一氧化氮引起血管平滑肌细胞的超极化和cGMP升高。目前尚不清楚硝酸甘油是否通过增加蛛网膜下腔出血（SAH）后的cGMP水平来改善血管痉挛。第一项研究的目的是测量灵长类动物模型大脑动脉和大脑顶叶皮层中cGMP和cAMP的水平，并确定硝酸甘油对SAH后血管痉挛的影响。在右大脑中动脉（MCA）周围放置血栓可引起慢性血管痉挛。术后7天，再次行血管造影，静脉滴注硝酸甘油或生理盐水。两侧脑动脉出现明显的血管痉挛，右侧更为明显。同时，右侧rCBF明显减少。在右MCA，cGMP水平明显低于正常MCA。硝酸甘油给药3小时后，两侧脑血管明显扩张，右侧rCBF明显增加，左侧rCBF明显增加。虽然右MCA的cGMP水平下降没有被硝酸甘油恢复，但在基底动脉中观察到cGMP水平显著升高。在两个顶叶皮层，SAH后cGMP水平显著降低，硝酸甘油治疗后保持不变。在SAH和硝酸甘油治疗后，cAMP水平没有明显变化。综上所述，硝酸甘油在痉挛性MCA中的血管扩张作用可能不是通过cGMP水平的增加来介导的，这可能与平滑肌细胞的超极化有关。

Nitroglycerin, as well as nitric oxied, causes hyperpolarization and cGMP elevation in vascular smooth muscle cells. It is unknown whether nitroglycerin ameliorates vasospasm by an increase in cGMP levels after sudarachnoid hemorrhage (SAH). The purpose of the first study was to measure the levels of cGMP and cAMP in the cerebral arteries and parietal cerebral cortices in a primate model and to determine the effect of nitroglycerin on vasospasm after SAH.Chronic vasospasm was induced by clot placement around the right middle cerebral artery (MCA). Seven days after the surgery, angiography was repeated and either nitroglycerin or saline was administered intrevenously. A significant vasospasm occurredin the cerebral arteries on both sides, more prominently on the right side. Concomittantly, rCBF on the right side was significantly decreased. In the right MCA,cGMP levels were significantly lower than in the normal MCA.After the administration of nitroglycerin for 3 hours, the cerebral vessels were significantly dilated on both sides, and rCBF was singnificantly increased on the right side but not on the left side. Although depressed cGMP levels in the right MCA were not recovered by nitroglycerin, a significant increase in cGMP levels was observed in the basilar artery. In both parietal cortices, cGMP levels were significantly decreased after SAH and unchanged after nitroglycerin treatment. There were no significant changer in cAMP levels in SAH and after nitroglycerin treatment. In conclusion, the vasodilator effect of nitroglycerin in spastic MCA may not be mediated by an increase in cGMP levels, suggesting an involvement of hyperpolarization of the smooth muscle cells.