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Mechanisms of amphetamine action illuminated through optical monitoring of dopamine synaptic vesicles in Drosophila brain

Freyberg, Zachary; Sonders, Mark S.; Aguilar, Jenny I.; Hiranita, Takato; Karam, Caline; Flores, Jorge; Pizzo, Andrea B.; Zhang, Yuchao; Farino, Zachary; Chen, Audrey; Martin, Ciara A.; Kopajtic, Theresa A.; Fei, Hao; Hu, Gang; Lin, Yi-Ying; Mosharov, Eugene V.; McCabe, Brian D.; Freyberg, Robin; Wimalasena, Kandatege; Hsin, Ling-Wei; Sames, Dalibor; Krantz, David E.; Katz, Jonathan L.; Sulzer, David L.; Javitch, Jonathan A.

Amphetamines elevate extracellular dopamine, but the underlying mechanisms remain uncertain. Here we show in rodents that acute pharmacological inhibition of the vesicular monoamine transporter (VMAT) blocks amphetamine-induced locomotion and self-administration without impacting cocaine-induced behaviours. To study VMAT’s role in mediating amphetamine action in dopamine neurons, we have used novel genetic, pharmacological and optical approaches in Drosophila melanogaster. In an ex vivo whole-brain preparation, fluorescent reporters of vesicular cargo and of vesicular pH reveal that amphetamine redistributes vesicle contents and diminishes the vesicle pH-gradient responsible for dopamine uptake and retention. This amphetamine-induced deacidification requires VMAT function and results from net H+ antiport by VMAT out of the vesicle lumen coupled to inward amphetamine transport. Amphetamine-induced vesicle deacidification also requires functional dopamine transporter (DAT) at the plasma membrane. Thus, we find that at pharmacologically relevant concentrations, amphetamines must be actively transported by DAT and VMAT in tandem to produce psychostimulant effects.

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Title
Nature Communications
DOI
https://doi.org/10.1038/ncomms10652

More About This Work

Academic Units
Psychiatry
Neuroscience
Chemistry
Neurology
Publisher
Nature Publishing Group
Published Here
September 17, 2016
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