The roles played by nitric oxide (NO) and endothelin (ET) in the genesis of sympathetic nervous activation following experimental subarachnoid haemorrhage was investigated using spectral analysis of blood pressure rhythms. 2. Subarachnoid haemorrhage was induced in conscious rats by injecting 0.3 mL homologous blood via a catheter placed along the surface of the brain and directed towards the circle of Willis. Three hours after the insult and after sympathetic activation was evident, animals received either an acute injection of the ET antagonist bosentan (5 mg/kg, i.v.; n = 7), an infusion of the NO donor sodium nitroprusside (SNP; 18 microg/h; n = 7) or no treatment (n = 7). 3. Three hours following the induction of subarachnoid haemorrhage, the mid-frequency components of systolic blood pressure were markedly elevated, indicating a pronounced sympathoexcitation. However, blood pressure and heart rate levels remained unchanged at this time. In the absence of treatment, the mid-frequency components of blood pressure remained elevated for a subsequent 2 h. Treatment with a non-hypotensive dose of SNP reversed the sympathoexcitation within 1 h. Treatment with bosentan was also effective in reducing the mid-frequency oscillations in blood pressure associated with subarachnoid haemorrhage. 4. Our results indicate that subarachnoid haemorrhage is associated with an acute activation of the sympathetic nervous system. The degree of sympathoexcitation can be reversed by the use of either bosentan or SNP.
摘要
利用血压节律的频谱分析，研究了一氧化氮（NO）和内皮素（ET）在实验性蛛网膜下腔出血后交感神经激活发生过程中所起的作用。2. 通过沿脑表面放置并指向 Willis 环的导管向清醒大鼠注射 0.3 mL 同源血液，诱导蛛网膜下腔出血。在损伤后 3 小时且交感神经激活明显后，动物分别接受急性注射 ET 拮抗剂波生坦（5 mg/kg，静脉注射；n = 7）、输注 NO 供体硝普钠（SNP；18 μg/h；n = 7）或不进行治疗（n = 7）。3. 蛛网膜下腔出血诱导后 3 小时，收缩压的中频成分显著升高，表明存在明显的交感神经兴奋。然而，此时血压和心率水平保持不变。在未治疗的情况下，血压的中频成分在随后 2 小时内仍保持升高。用非降压剂量的 SNP 治疗可在 1 小时内逆转交感神经兴奋。用波生坦治疗也能有效降低与蛛网膜下腔出血相关的血压中频振荡。4. 我们的结果表明，蛛网膜下腔出血与交感神经系统的急性激活有关。使用波生坦或 SNP 均可逆转交感神经兴奋程度。
