ABSTRACT
The Nitric Oxide [NO] is an essential regulatory molecule in vascular tone and integrity 2. previous studies has supported the role of NO in remodeling of axons arbors and acts as an activity dependent retrograde signal during the refinement of visual Connections 14, 4 and5. Recently, it was found that NO has been implicated in retinal pathogenesis of retinal vasculogenesis in development of retinal neovascularization [NV] in ischemic retinopathies 17, NADPH-diaphorase reaction reflects NOS activity in the retina and neural tissue 3, 17, 1, 2, 13, 6, 16, 20 and7. NADPH-diaphorase staining neurons, have been localized with neurons in the brain and peripheral tissue containing nitric oxide synthase, which generates NO. NADPH- diaphorase staining are localized in the pedunculopontine nucleus and colocalized in amacrine cells of the inner nuclear layer and ganglion cells of the retina. NADPH-diaphorase has been shown to be a reliable marker of nNOS activity in neuronal tissue 16 and1 NADPH-diaphorase reaction was, therefore used in this study for localizing the development of retinal vasculature as well as any related neuronal tissue