Aerobic exercise in adolescence results in an increase of neuronal and non-neuronal cells and in mTOR overexpression in the cerebral cortex of rats

•Aerobic exercise in adolescent rats increased the number of neuronal and non-neuronal cells in cerebral cortex.•More neuronal cells were found in the hippocampal formation of rats submitted to aerobic exercise during adolescence.•mTOR overexpression was detected in the cortex of exercised adolescent rats, although not in the hippocampal formation.•Our data indicate a cellular proliferative effect of aerobic exercise on the cerebral cortex in postnatal development.

Better cognitive performance and greater cortical and hippocampal volume have been observed in individuals who undertook aerobic exercise during childhood and adolescence. One possible explanation for these beneficial effects is that juvenile physical exercise enables better neural development and hence more cells and neuronal circuitries. It is probable that such effects occur through intracellular signaling proteins associated with cell growth, proliferation and survival. Based on this information, we evaluated the number of neuronal and non-neuronal cells using isotropic fractionation and the expression and activation of intracellular proteins (ERK, CREB, Akt, mTOR and p70S6K) in the cerebral cortex and hippocampal formation of the rats submitted to a physical exercise program on a treadmill during adolescence. Results showed that physical exercise increases the number of neuronal and non-neuronal cortical cells and hippocampal neuronal cells in adolescent rats. Moreover, mTOR overexpression was found in the cortical region of exercised adolescent rats. These findings indicate a significant cellular proliferative effect of aerobic exercise on the cerebral cortex in postnatal development.