The present study observed changes in rat neural cells at various ages (3, 18, 24, and 30 months). With age, neural cells became large and were sparsely arranged, and the number of Nissl bodies decreased. In addition, hypoxia-inducible factor 1α expression increased with increasing age in hippocampal CA1 and CA3 regions, motor cortex, and the first subfolium, especially from 3 to 18 months. In the open-field test, grid crossing decreased with increasing age, especially from 18 months. The number of rearings reached a peak in the 18 months group, and then subsequently decreased. The results suggested that hypoxia-inducible factor 1α played an important role in the nervous system aging process. The present study observed changes in rat neural cells at various ages (3, 18, 24, and 30 months). With age, neural cells became large and were sparsely arranged, and the number of Nissl bodies decreased. In addition, hypoxia-inducible factor 1α expression increased with increasing age in hippocampal CA1 and CA3 regions, motor cortex, and the first subfolium, especially from 3 to 18 months. In the open-field test, grid crossing decreased with increasing age, especially from 18 months. The number of rearings reached a peak in the 18 months group, and then subsequent decreased. The results suggesting that hypoxia-inducible factor 1α played an important role in the nervous system aging process.