Chronic voluntary exercise induces plasticity of noradrenaline-activated dopamine D1-like receptor signaling

Physical exercise has lasting positive influence on mental health. However, its cellular substrate remains to be elucidated. Recently, dopamine D₁-like receptor activation induced by noradrenaline has been suggested to underlie exercise-dependent augmentation of antidepressant effects. The present study demonstrates that exercise induces a long-term enhancement of this atypical catecholaminergic signaling. Noradrenaline potentiates hippocampal mossy fiber synaptic transmission by activating D₁-like receptors in mice. Voluntary exercise by wheel running enhanced this noradrenaline-D₁-like receptor signaling within 5 days. The enhancement of the noradrenaline-D₁-like receptor signaling did not require the integrity of noradrenergic fibers and was maintained for more than 2 weeks after cessation of wheel running. Notably, the effect of exercise was more robustly seen in D₁-like receptor signaling activated by noradrenaline as compared with dopamine, indicating particular responsiveness of the noradrenaline-activated D₁-like receptor signaling to exercise. These results suggest that exercise could exert lasting influence on brain functioning via plasticity of the hippocampal noradrenaline-D₁-like receptor signaling.