NO production during neuronal cell death can be directly assessed by a chemical reaction in vivo

THE role of nitric oxide (NO) as a putative mediator of neuronal death can be understood best if NO is detected directly. For this purpose, we develop ed a new sensitive method that for the first time directly captures release d NO during neurodegeneration in vivo and at the cellular site of its gener ation. The non-fluorescent substance 1,2-diaminoanthraquinone (DAA) was inj ected into the eyes of rats whose optic nerve was injured to induce retrogr ade degeneration of the ganglion cells. The reaction product of DAA with NO is a triazole with red fluorescence. The two major NO producing cell popul ations in the retina are capillary endothelial cells and microglial cells. The methodology of NO assessment is convenient and applicable to numerous l iving systems both in vivo and in vitro. (C) 1998 Lippincott Williams & Wil kins.