ABSTRACT
Here, we investigated the temporal change of post synapse signaling molecules, post synaptic density-95 (PSD-95) and neuronal nitric oxide synthase (nNOS) using immunohistochemistry during voluntary running with upregulated neurogenesis. Rate of running was stabilized after two weeks of the six week trial. By using immunohistochemsitry for phosphorylated cAMP response element binding protein (pCREB) and polysialylatedneural cell adhesion molecules (PSA-NCAM), we observed that the differentiation in dentate granule cells of adult mouse hippocampus increased at 1 and 2 weeks of voluntary running. We found that, at 6 weeks of voluntary running, the differentiation in dentate granule cells of adult mouse hippocampus returned to sedentary control levels. On the other hand, PSD-95 and nNOS immunoreactivity decreased in the inner molecular layer in the dentate gyrus of hippocampus after 1 and 2 weeks of voluntary running. At 6 weeks of voluntary running, the density of the PSD-95 and nNOS in the inner molecular layer was returned to the sedentary control level. The reactivity of nicotinamide dinucleotide phosphate diaphorase (NADPH-diaphorase), the marker of nitric oxide synthase activity, confirmed the change of nNOS in the inner molecular layer during voluntary running. These results demonstrate that the differentiation and the synaptic activity of granule cells during voluntary running are changed reciprocally once the rate of running has stabilized. These granule cell changes during voluntary running suggest an adaptation response to the new environment.