IMMUNOHISTOCHEMICAL LOCALIZATION OF ENDOTHELIAL NITRIC-OXIDE SYNTHASEIN VESSELS OF THE DURA-MATER OF THE SPRAGUE-DAWLEY RAT

Nitric oxide (NO) and the dura mater are implicated in the pathogenesi s of vascular headache. Many studies have demonstrated the participati on of NO in headache; however, few studies have identified NO in the d ura mater. In this study, nine Sprague-Dawley rats were examined with immunohistochemistry using two different endothelial nitric oxide synt hase (eNOS) monoclonal antibodies, H32 and ECNOS. eNOS was successfull y localized to the endothelium of the middle meningeal artery. To the best of our knowledge, this is the first study to report NOS immunopos itive endothelial cells in the blood vessels of the rat dura mater. Th e authors propose that NO plays an active role in dural vasodilation, contributing to the pathogenesis of vascular headache; in the future, NO inhibitors could serve as pharmacological agents to treat vascular headache.