SLC18A2 and Parkinson disease: DPP-4 inhibitors also reduced symptoms of Parkinson’s disease possibly by decreasing dopamine depletion via intensification of tyrosine hydroxylase and vesicular monoamine transporter 2 (VMAT2) [51] or via stimulation of antioxidant, anti-inflammatory, antiapoptotic, neuroprotective and neurorestorative mechanisms [68,69].