目的　探讨内毒素血症大鼠内皮素-1与脑血管痉挛发生与发展的关系。　方法　96只　Wistar大鼠随机分为对照组、内毒素血症组(注射内毒素第3、6、12、24、48 h)，以放射免疫检测血浆内皮素　-1水平的变化，免疫组织化学ABC法对大鼠大脑中动脉内皮素-1能神经纤维进行染色观察。　结果　内毒素血症后3、6、12 h大鼠血浆内皮素-1水平较对照组明显升高(P<0.05)，内毒素血症后24和48 h已趋于正常(P>0.05)。对照组和内毒素血症大鼠大脑中动脉可见棕褐色、呈细线状内皮素-1能免疫反应阳性纤维，以内毒素血症后第6、12 h大鼠大脑中动脉内皮素-1免疫反应最为显著(P<0.05）。　结论　内毒素血症后，大鼠内皮素-1合成和释放入血水平升高，脑血管神经纤维内皮素-1的表达水平上调，这两种因素可能同时参与了脑血管痉挛的发生与发展。

Objective　To investigate the relationship between endothelin-1(ET-1) and cerebral vasospasm in endotoxemia rats.　Methods　96 Wistar rats were randomly divided into control and experimental groups, the latter was then subdivided into 3, 6, 12, 24 and 48-h groups after the injection of lipopolysaccharide (LPS). The alteration of plasma ET-1 was detected by radioimmunoassay technique, and ET-1 immunoreactive nerve fibers in middle cerebral artery were examined with immunohistochemistry and measured with stereoscopy method.　Results　LPS treatment caused a significant increase of plasma ET-1 concentration at 3, 6 and 12 h after the treatment compared to that of control (P<0.05). For 24 and 48-h LPS-treated groups, the plasma ET-1 decreased and closed to the normal level (P>0.05). The ET-1 immunoreactive nerve fibers were observed in all groups, which were brown and thin line-shaped. Moreover, at 6 and 12 h after LPS treatment, the density of ET-1 immunoreactive nerve fibers on middle cerebral arteries was much higher than that of the controls (P<0.05).　Conclusions　Our findings suggest that, after endotoxemia, the elevated plasma ET-1 concentration, as well enhanced ET-1 immunoreactivity in cerebral arterial nerve fibers, are both involved in the development of cerebral vasospasm induced by endotoxemia.