Neuronal Activity in Rat Hippocampus During Light-Intensity Treadmill Running.

In the early 2000s, it became evident that exercise enhances brain function, particularly in the hippocampus, attracting considerable attention. However, at that time, most studies relied on the voluntary wheel running model for experiments, it was unclear whether exercise conditions affected the impact of exercise on the hippocampus. Therefore, aiming to obtain translational insights applicable to humans, we focused on exercise intensity and started with the research investigating whether light-intensity exercise activates hippocampal neural activity in rats. We established an original running model in rats comprising laser Doppler flowmetry for monitoring hippocampal cerebral blood flow (Hip-CBF) and microdialysis for drug treatment. We found that Hip-CBF increased with light-intensity treadmill running, which was elicited by hippocampal neuronal activation and subsequent N-methyl-D-aspartate/nitric oxide (NMDA/NO) signaling. In this chapter, we first retrospectively summarize what we knew and what we did not know during that time, and the impact of our findings that light-intensity exercise can evoke neuronal activity in the rat hippocampus on our subsequent research.