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Amphetamine augments action potential‐dependent dopaminergic signaling in the striatum in vivo
Author(s) -
Ramsson Eric S.,
Covey Daniel P.,
Daberkow David P.,
Litherland Melissa T.,
Juliano Steven A.,
Garris Paul A.
Publication year - 2011
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2011.07258.x
Subject(s) - striatum , dopaminergic , amphetamine , dopamine , in vivo , chemistry , basal ganglia , pharmacology , extracellular , neuroscience , ventral striatum , biology , central nervous system , biochemistry , microbiology and biotechnology
J. Neurochem. (2011) 117 , 937–948. Abstract Amphetamine (AMPH) is thought to disrupt normal patterns of action potential‐dependent dopaminergic signaling by depleting dopamine (DA) vesicular stores and promoting non‐exocytotic DA efflux. Voltammetry in brain slices concurrently demonstrates these key drug effects, along with competitive inhibition of neuronal DA uptake. Here, we perform comparable kinetic and voltammetric analyses in vivo to determine whether AMPH acts qualitatively and quantitatively similar in the intact brain. Fast‐scan cyclic voltammetry measured extracellular DA in dorsal and ventral striata of urethane‐anesthetized rats. Electrically evoked recordings were analyzed to determine K m and V max for DA uptake and vesicular DA release, while background voltammetric current indexed basal DA concentration. AMPH (0.5, 3, and 10 mg/kg i.p.) robustly increased evoked DA responses in both striatal subregions. The predominant contributor to these elevated levels was competitive uptake inhibition, as exocytotic release was unchanged in the ventral striatum and only modestly decreased in the dorsal striatum. Increases in basal DA levels were not detected. These results are consistent with AMPH augmenting action potential‐dependent dopaminergic signaling in vivo across a wide, behaviorally relevant dose range. Future work should be directed at possible causes for the distinct in vitro and in vivo pharmacology of AMPH.