CONICET | Buscador de Institutos y Recursos Humanos

Aerobic exercise (AE) benefits brain health and behavior. Serotonin (5-HT) and brain-derived neurotrophicfactor (BDNF) are known to mediate and shape cognitive processes. Both systems share some actions: BDNF isinvolved in the maturation and function of 5-HT neurons. In turn, 5-HT is involved in neuroplasticity phenomenamediated by BDNF and stimulated by exercise. The aim of this work was to study the long-term effects of AE onBDNF- 5-HT systems and cognitive function in rats at different ages. A lifelong moderate-intensity aerobictraining program was designed, in which aerobically exercised (E) and sedentary control (C) rats were studied atmiddle (8 months) and old age (18 months) by means of biochemical, immunohistochemical and behavioralassays. The levels and expression of BDNF, 5-HT, serotonin transporter (SERT) and 5-HT1A receptor were determinedin selected brain areas involved in memory and learning. Immunopositive cells to neuronal nuclearprotein (NeuN) in the hippocampus CA1 area were also quantified. The cognitive function was evaluated by theobject recognition test (ORT). Results indicate that AE enhanced spatial and non-spatial memory systems,modulated by age. This outcome temporarily correlated with a significant upregulation of cortical, hippocampaland striatal BDNF levels in parallel with an increase in the number of hippocampal CA1-mature neurons. AE alsoincreased brain and raphe 5-HT levels, as well as the expression of SERT and 5-HT1A receptor in the cortex andhippocampus. Old AE rats showed a highly conserved response, indicating a remarkable protective effect ofexercise on both systems. In summary, lifelong AE positively affects BDNF-5-HT systems, improves cognitivefunction and protects the brain against the deleterious effects of sedentary life and aging.