Short bouts of mild-intensity physical exercise improve spatial learning and memory in aging rats: involvement of hippocampal plasticity via AKT, CREB and BDNF signaling.

In the present study, we investigated whether mild-intensity physical exercise represents a successful strategy to enhance spatial learning and memory and hippocampal plasticity in aging rats, as previously described for long-term exposure to running wheel or treadmill exercise. Aging Wistar rats were submitted to short bouts (4-6 min) of exercise treadmill during five consecutive weeks. This mild-intensity exercise program increased muscle oxygen consumption by soleus and heart in aging rats and reversed age-related long-term spatial learning and memory impairments evaluated in the water maze and step-down inhibitory avoidance tasks. Remarkably, the observed cognitive-enhancing properties of short bouts of exercise were accompanied by the activation of serine/threonine protein kinase (AKT) and cAMP response element binding (CREB) pro-survival signaling that culminates in the marked increase on the brain-derived neurotrophic factor (BDNF) mRNA expression and BDNF protein levels on the hippocampus of aging rats. Altogether, these results indicate that short bouts of exercise represent a viable behavioral strategy to improve cognition and synaptic plasticity in aging rats which should be taken into account in further studies addressing the effects of physical exercise in aging subjects.