Abstract
The dopamine transporter, DAT, is a primary regulator of dopamine (DA) signaling at the synapse. Persistent stimulation with the substrate amphetamine (AMPH) promotes DAT internalization. AMPH rapidly elicits DA efflux, yet its effect on DAT trafficking at short times is unknown. We examined the rapid effect of AMPH on DAT trafficking in rat striatal synaptosomes using biotinylation to label surface DAT. Within 30s of treatment with 3 microM AMPH, synaptosomal DAT surface expression increased to 163% of control and remained elevated through at least 1 min before returning to control levels at 2.5 min. The increase in surface DAT was cocaine-sensitive but was not produced by DA itself. A 1-min preincubation with AMPH did not alter [(3)H]DA uptake, but did result in a higher basal DA efflux and efflux elicited in the presence of AMPH as compared to vehicle pretreatment. Reversible biotinylation experiments demonstrated that the AMPH-stimulated rise in surface DAT is due to an increase in the delivery of DAT to the plasmalemmal membrane rather than a reduction of the endocytic process. These studies suggest that AMPH has a biphasic effect on DAT trafficking and acts rapidly to regulate DAT in the plasmalemmal membrane.
Publication types
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Comparative Study
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Research Support, N.I.H., Extramural
MeSH terms
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Amphetamine / administration & dosage*
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Animals
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Biotin / metabolism
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Biotinylation / methods
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Cell Line
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Cocaine / analogs & derivatives
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Cocaine / pharmacokinetics
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Corpus Striatum / cytology*
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Corpus Striatum / drug effects
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Diagnostic Imaging / methods
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Dopamine / metabolism
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Dopamine / pharmacology
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Dopamine Plasma Membrane Transport Proteins / metabolism*
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Dopamine Uptake Inhibitors / administration & dosage*
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Drug Administration Schedule
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Electrophoresis, Polyacrylamide Gel / methods
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Endocytosis / drug effects
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Endocytosis / physiology
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Exocytosis / drug effects
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Exocytosis / physiology
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Gene Expression Regulation / drug effects
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Green Fluorescent Proteins / metabolism
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Humans
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Protein Binding / drug effects
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Protein Transport / drug effects
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Rats
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Subcellular Fractions / drug effects
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Subcellular Fractions / metabolism
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Synaptosomes / drug effects*
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Time Factors
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Transfection / methods
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Tritium / metabolism
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Tritium / pharmacokinetics
Substances
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Dopamine Plasma Membrane Transport Proteins
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Dopamine Uptake Inhibitors
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Tritium
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Green Fluorescent Proteins
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(1R-(exo,exo))-3-(4-fluorophenyl)-8-methyl-8- azabicyclo(3.2.1)octane-2-carboxylic acid, methyl ester
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Biotin
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Amphetamine
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Cocaine
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Dopamine