NADPH-diaphorase histochemistry in the rat cerebral cortex and hippocampus: effect of electrolytic lesions of the nucleus basalis magnocellularis

Unilateral or bilateral electrolytic lesions of the nucleus basalis magnoce llularis (NBM) increased NADPH-diaphorase in the fronto-parietal cortex and in the CA(1)-CA(3) fields of the hippocampus. NBM is the cholinergic basal forebrain nucleus supplying the fronto-parietal cortex but not the hippoca mpus. This increase was more remarkable at 4 weeks than at 2 weeks after le sioning. Monolateral or bilateral lesioning of the NBM increased to a simil ar extent NADPH-diaphorase. The number of neurons expressing NADPH-diaphora se was not statistically different between sham-operated and NBM-lesioned r ats. These results indicate that similarly as reported in experimental dama ge of several brain areas, lesions of the NBM induce NADPH-diaphorase. The induction of this marker for nitric oxide synthase occurs both in the targe t of projections arising from the NBM such as the frontal cortex and in an area not directly supplied by NBM such as the hippocampus. Lesion-induced N ADPH-diaphorase increase may contribute to neurodegenerative changes caused by damage of the NBM area. (C) 1999 Elsevier Science Ireland Ltd. All righ ts reserved.