REGIONAL CHANGES OF NADPH-DIAPHORASE AND NEUROPEPTIDE-Y NEURONS IN THE CEREBRAL-CORTEX OF AGED FISCHER-344 RATS

This study examined the effects of aging on neuropeptide Y (NPY) and N ADPH-diaphorase (NADPH-d)-positive neurons of the cerebral cortex in y oung (3 months) and aged (24 months) Fischer 344 rats by immunohistoch emical and histochemical methods. In the aged group, the number of NPY -immunoreactive (IR)/NADPH-d-positive neurons was not significantly ch anged in all regions of the cerebral cortex compared to the control gr oup. However, the number of NPY-IR/NADPH-d-negative neurons was signif icantly decreased in frontal association, primary motor, secondary som atosensory, insular, ectorhinal, perirhinal and auditory cortex in the aged group. In the aged rats, about 5-10% of NPY-IR/NADPH-d-positive neurons were dystrophic and scattered within the cerebral cortex. Thes e results suggested that NPY-IR neurons that do not contain NADPH-d ar e affected by aging and that aging influences NPY-IR/NADPH-d-negative neurons in a region-specific pattern within the cerebral cortex of rat s. (C) 1998 Elsevier Science Ireland Ltd.