Midbrain dopamine (DA) neurons are comprised of diverse neuronal subpopulations. For instance, there are subsets of DA neurons that express the vesicular glutamate transporter VGLUT2 and these cells can co-release the excitatory neurotransmitter glutamate. There are also several lines of evidence indicating that the inhibitory neurotransmitter gamma-amino-butyric acid (GABA) can be released from subsets of DA neurons. However, DA neurons do neither express the machinery to synthesize GABA nor the vesicular GABA transporter VGAT typically thought to be necessary for vesicular GABA uptake. Instead, recent evidence suggests that GABA is taken up into DA neurons by virtue of the plasmalemmal GABA transporter GAT1. Cytosolic GABA can then be stored in synaptic vesicles via the vesicular monoamine transporter VMAT2 which is the main transporter for vesicular DA storage. Here we use radiotracer flux measurements in VMAT2 expressing cells, and purified striatal synaptic vesicles to determine whether GABA or other related small molecules qualify as potential substrates for VMAT2. We also investigate whether GABA uptake may occur in human midbrain neurons.