NADPH-DIAPHORASE (NOS) IS INDUCED IN PYRAMIDAL NEURONS OF HIPPOCAMPALSLICES

WE found NADPH-diaphorase (presumably identical with nitric oxide synt hase) in pyramidal neurones of the hippocampus in slices that stayed i n a chamber for 30 min or longer. In some instances parallel slices sh owed normal membrane properties when studied electrophysiologically. I n freshly made slices the pyramidal neurones were not stained. Thus, a fter induction of the enzyme, the hippocampal pyramidal neurones can s ynthesize nitric oxide which may serve as a retrograde messenger in lo ng-term potentiation. The enzyme may also play a role in cell loss see n in slices which stayed in a chamber for 9-22 h before fixation.