A Study on the Distribution of NADPH-Diaphorase and Neuropeptide Y Positive Neurons in the Cerebral Cortex of Apodemus Agrarius

Huh, Young Bum; Hwang, Seung Joon; Jo, Jung Sik

Abstract

Apodemus agrarius has been using for experimental purpose to identifying the route of infection and pathogenesis of korean hemorrhagic fever. However, despite the increasing amount of information being published at present about the physiologic and ecologic characteristics of Apodemus, few data are availalle about the morphologic findings in the brain. The NADPH-diaphorase[NADPH-d] positive neurons, uniquely resistant to toxic insults and neurodegenerative diseases, have been colocalized with neurons in the brain and peripheral tissue containing nitric oxide synthase, which generates nitric oxide, a recently identified neuronal messenger molecule. In this study we used NADPH-d histochemistry to evaluate the distribution of neuropeptide Y-immunoreactive[NPY-IR] cells within neurons which contain nitric oxide synthase. In the cerebral cortex of Apodemus agrarius, NADPH-d positive and NPY-IR neurons were observed in all cortical layers, but they were concentrated in two bands layer II/III and V/VI extending into the subcortical white matter. Double labeling for NADPH-d and NPY showed colocalization of NPY with NADPH-d in numerous neurons of the cerebral cortex. The data obtained showed that about 74-79% of NPY-IR neurons contained NADPH-d in the neocortex and that 77-89% in the allocortex. The number of NPY-IR/NADPH-d positive neurons was about 10-13 per unit area [2,500,000 micrometer] in the neocortex and about 11-25 in the allocortex except retrosplenial cortex. In the retrosplenial cortex, the number of double labeled neurons was about 5 per unit area. NPY-IR and NADPH-d positive neurons were predominantly medium-sized with extended, multipolar or bipolar dendritic branches which belong to fusiform or stellate cell types. A moderately dense network of fine, varicose NADPH-d positive fibers was present throughout all cortical layers.