In dopamine synthesis, tyrosine hydroxylase (TH) serves as the rate-limiting enzyme,17 and Erk is reported to regulate the expression of TH.18 While electrostimulation has been shown to elevate dopamine levels in the midbrain,19 we examined whether loading to the tibia upregulates TH via Erk signaling and promotes dopamine synthesis in the ventral tegmental area (VTA), which includes abundant dopaminergic neurons.20 In addition, we sought to determine whether tibial loading induces dopamine-mediated suppression of brain tumors via D1- or D2-type dopamine receptors. This evidence concerns the gene TH and brain neoplasm.