Treadmill exercise enhances nitric oxide synthase expression in the hippocampus of food-deprived rats

Nitric oxide (NO) is endogenously synthesized from l-arginine by the enzyme NO synthase (NOS). Three isoforms of NOS have been characterized: neuronal NOS (nNOS), endothelial NOS, and inducible NOS. Acting as a neuronal messenger in the brain, NO is crucial in learning and memory processes. Starvation is known to decrease learning ability and memory capability. In the present study, we examined the effect of treadmill exercise on the expression of NOS and nNOS in the hippocampus of food-deprived rats. Food deprivation suppressed the NOS and nNOS expression in the CA1 region, the CA2 and CA3 regions, and the dentate gyrus of the hippocampus. We have observed that treadmill running overcomes the food deprivation-induced suppression of the NOS and nNOS expression in the various hippocampal regions. The present results suggest that treadmill exercise may overcome the starvation-induced decrease of learning ability and memory function in the hippocampus.