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cGMP水平来缓解血管痉挛。第一项研究的目的是在灵长类动物模型中检测大脑动脉和顶叶皮质中cGMP和cAMP的水平，并确定硝酸甘油对SAH后血管痉挛的影响。术后7天重复血管造影术，静脉注射硝酸甘油或生理盐水。双侧脑动脉均出现明显的血管痉挛，右侧更为明显。同时，右侧rCBF显著降低。给予硝酸甘油3h后，双侧脑血管明显扩张，右侧rCBF显著增加，左侧无明显变化。虽然硝酸甘油不能使右侧大脑中动脉cGMP水平恢复，但基底动脉cGMP水平显著升高。SAH后双侧顶叶皮质cGMP水平显著降低，硝酸甘油治疗后无明显变化。SAH患者及硝酸甘油治疗后cAMP水平无明显变化。结论：硝酸甘油对痉挛MCA的血管扩张作用可能不是通过增加cGMP水平实现的，提示可能参与了血管细胞的超极化。

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.