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Download fileAmphetamine Paradoxically Augments Exocytotic Dopamine Release and Phasic Dopamine Signals
journal contribution
posted on 2013-12-06, 00:00 authored by D.P. Daberkow, H.D. Brown, K.D. Bunner, S.A. Kraniotis, M.A. Doellman, M.E. Ragozzino, P.A. Garris, M.F. RoitmanDrugs of abuse hijack brain-reward circuitry during the addiction process by augmenting action potential-dependent phasic dopamine
release events associated with learning and goal-directed behavior. One prominent exception to this notion would appear to be amphetamine
(AMPH) and related analogs, which are proposed instead to disrupt normal patterns of dopamine neurotransmission by depleting
vesicular stores and promoting nonexocytotic dopamine efflux via reverse transport. This mechanism of AMPH action, though, is
inconsistent with its therapeutic effects and addictive properties, which are thought to be reliant on phasic dopamine signaling. Here we
used fast-scan cyclic voltammetry in freely moving rats to interrogate principal neurochemical responses to AMPH in the striatum and
relate these changes to behavior. First, we showed that AMPH dose-dependently enhanced evoked dopamine responses to phasic-like
current pulse trains for up to 2 h. Modeling the data revealed that AMPH inhibited dopamine uptake but also unexpectedly potentiated
vesicular dopamine release. Second, we found that AMPH increased the amplitude, duration, and frequency of spontaneous dopamine
transients, the naturally occurring, nonelectrically evoked, phasic increases in extracellular dopamine. Finally, using an operant sugar
reward paradigm, we showed that low-dose AMPH augmented dopamine transients elicited by sugar-predictive cues. However, operant
behavior failed at high-doseAMPH,which was due to phasic dopamine hyperactivity and the decoupling of dopamine transients from the
reward predictive cue. These findings identify upregulation of exocytotic dopamine release as a key AMPH action in behaving animals
and support a unified mechanism of abused drugs to activate phasic dopamine signaling.
Funding
This work was supported by the National Institute on Drug Abuse (Grants DA021770 and DA024036 to P.A.G. and DA025634 to M.F.R.), the National Institute of Child Health and Human Development (Grant HD055751 to M.E.R.), the National Science Foundation (Grant DBI0754615 to P.A.G.) and Illinois State University (grants to P.A.G.).
History
Publisher Statement
This is a copy of an article published in the Journal of Neuroscience © 2013 Society for Neuroscience. The publication is available at http://www.jneurosci.org/.Citation
Daberkow DP, Brown HD, Bunner KD, Kraniotis SA, Doellman MA, Ragozzino ME, Garris PA, Roitman MF. Amphetamine paradoxically augments exocytotic dopamine release and phasic dopamine signals. Journal of Neuroscience. 2013 Jan 9;33(2):452-63. doi: 10.1523/JNEUROSCI.2136-12.2013.Publisher
Society for NeuroscienceLanguage
- en_US