GLUTAMATE AGONIST-INDUCED HIPPOCAMPAL LESION AND NITRIC-OXIDE SYNTHASE NADPH-DIAPHORASE - A LIGHT AND ELECTRON-MICROSCOPIC STUDY IN THE RAT

The 2-(2'-benzothiazolyi)-5-styryl-3-(4'-phthalhydrazidyl) tetrazolium chloride (BSPT)-tetrazolium salt technique for the electron microscopic demonstration of reduced nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) was used to localize nitric oxide synthase in the normal and excitotoxically lesioned rat hippocampus. The reaction product BSPT-formazan was shown to stain membranes predominantly of the endoplasmic reticulum. Apart from singular heavily labeled interneurons, the majority of neurons including pyramidal and granular cells and a few astroglial cells, light microscopically 'unstained', showed labeled membrane portions, but to a by far lesser extent. In lesioned areas some prominantly stained neurons rich in labeled membranes and surrounded by cell debris seemed to be largely preserved. An increased number of ultrahistochemically NADPH-d-stained glial cells, in particular astrocytes, was seen.