In situ hybridization study on the distribution of nNOS mRNA-positive neurons in the cerebral cortex and cerebellum of aged rats / 대한해부학회지

ABSTRACT

Nitric oxide (NO) is a diffusible cellular mediator generated by the enzyme nitric oxide synthase (NOS). NO involvement has been demonstrated in mechanisms of synaptic plasticity, particularly in hippocampal long-term potentiation, a mechanism that underlies certain forms of learning and memory. Several data have shown that NO production is decreased in the aged rat. Changes in the nNOS mRNA-containing neurons with aging were demonstrat-ed by in situ hybridization. nNOS mRNA-positive cells in aged rats were present in all cortical areas, hippocampus, and cerebellum and the distribution was similar to that of the young adult group. The number of nNOS mRNA-positive cells was significantly decreased in the occipital (86.2%), parietal (81.2%), and temporal cortices (79.4%), also in hippocampal CA1 (86.2%), dentate gyrus (92.3%), and cerebellar Purkinje cells (73.9%). The most severe decrease was found in hippocampal area. These results are consistent with the former studies showing NO decrease in aging brain and nNOS mRNA decrease indicates the involvement of neuronal system containing NOS in the aging brain, especially for learning and memory.