[Changes of nitric oxide and endothelin-1 levels in rat brain tissue during cerebral vasospasm following subarachnoid hemorrhage and protective effect of nimodipine].

Aim: To investigate the changes of nitric oxide and endothelin-1 levels in brain tissue in rat with cerebral vasospasm (CVS) following subarachnoid hemorrhage (SAH), and the protective effect of nimodipine.
Methods: Wistar rats were divided randomly into SAH group, nimodipine-treated group and sham-operated group. Diameters of basilar artery before and after operation were measured, and dynamic changes of regional cerebral blood flow (rCBF), brain nitric oxide and endothelin-1 levels were determined within 24 h. Pathological examination of hippocampus was also performed.
Results: SAH resulted in significant and persistent decrease of rCBF. Diameter of basilar artery was reduced markedly. Neurons in hippocampus CA1 subfield were damaged severely. Both nitric oxide and endothelin-1 levels in brain tissue were increased significantly from 1 h to 24 h after SAH. However, the pathological changes of above parameters were not so severe in nimodipine-treated rats.
Conclusion: Increase of nitric oxide and endothelin-1 levels in brain tissue is probably involved in the development of ischemic brain damage caused by CVS after SAH. Nimodipine exerts its protective effect on brain neurons by antagonizing CVS and the pathological changes of nitric oxide and endothelin-1 in brain tissue.