Amphetamine Modulates Excitatory Neurotransmission through Endocytosis of the Glutamate Transporter EAAT3 in Dopamine Neurons

•AMPH stimulates dynamin-mediated internalization of the glutamate transporter EAAT3•EAAT3 endocytosis requires AMPH transport into cells by DAT and Rho GTPase activation•A unique sequence on the C terminus of EAAT3 is required for internalization•Glutamatergic synaptic activity is enhanced by AMPH-mediated EAAT3 internalization

SummaryAmphetamines modify the brain and alter behavior through mechanisms generally attributed to their ability to regulate extracellular dopamine concentrations. However, the actions of amphetamine are also linked to adaptations in glutamatergic signaling. We report here that when amphetamine enters dopamine neurons through the dopamine transporter, it stimulates endocytosis of an excitatory amino acid transporter, EAAT3, in dopamine neurons. Consistent with this decrease in surface EAAT3, amphetamine potentiates excitatory synaptic responses in dopamine neurons. We also show that the process of internalization is dynamin- and Rho-mediated and requires a unique sequence in the cytosolic C terminus of EAAT3. Introduction of a peptide based on this motif into dopamine neurons blocks the effects of amphetamine on EAAT3 internalization and its action on excitatory responses. These data indicate that the internalization of EAAT3 triggered by amphetamine increases glutamatergic signaling and thus contributes to the effects of amphetamine on neurotransmission.