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Amphetamine-induced loss of human dopamine transporter activity : An internalization-dependent and cocaine-sensitive mechanism

Saunders, Christine; Ferrer, Jasmine V.; Shi, Lei; Chen, Jiayun; Merrill, Gerald; Lamb, Maria E; Leeb-Lundberg, Fredrik LU ; Carvelli, Lucia; Javitch, Jonathan A. and Galli, Aurelio (2000) In Proceedings of the National Academy of Sciences of the United States of America 97(12). p.6850-6855
Abstract

The dopamine transporter (DAT) is a target of amphetamine (AMPH) and cocaine. These psychostimulants attenuate DAT clearance efficiency, thereby increasing synaptic dopamine (DA) levels. Re-uptake rate is determined by the number of functional transporters at the cell surface as well as by their turnover rate. Here, we present evidence that DAT substrates, including AMPH and DA, cause internalization of human DAT, thereby reducing transport capacity. Acute treatment with AMPH reduced the maximal rate of [3H]DA uptake, decreased AMPH-induced currents, and significantly redistributed the immunofluorescence of an epitope-tagged DAT from the plasma membrane to the cytosol in human embryonic kidney 293 cells. Conversely, DAT... (More)

The dopamine transporter (DAT) is a target of amphetamine (AMPH) and cocaine. These psychostimulants attenuate DAT clearance efficiency, thereby increasing synaptic dopamine (DA) levels. Re-uptake rate is determined by the number of functional transporters at the cell surface as well as by their turnover rate. Here, we present evidence that DAT substrates, including AMPH and DA, cause internalization of human DAT, thereby reducing transport capacity. Acute treatment with AMPH reduced the maximal rate of [3H]DA uptake, decreased AMPH-induced currents, and significantly redistributed the immunofluorescence of an epitope-tagged DAT from the plasma membrane to the cytosol in human embryonic kidney 293 cells. Conversely, DAT inhibitors, such as cocaine, mazindol, and nomifensine, when administered with AMPH, blocked the reduction in [3H]DA uptake and the redistribution of DAT immunofluorescence to the cytosol. The reductions of [3H]DA uptake and AMPH- induced DAT internalization also were inhibited by coexpression of a dominant negative mutant of dynamin I (K44A), indicating that endocytosis modulates transport capacity, likely through a clathrin-mediated pathway. With this mechanism of regulation, acute application of AMPH would reduce DA uptake not only by direct competition for uptake, but also by reducing the available cell-surface DAT. Moreover, AMPH-induced internalization might diminish the amount of DAT available for DA efflux, thereby modulating the cytotoxic effects of elevated extracellular DA.

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author
publishing date
type
Contribution to journal
publication status
published
in
Proceedings of the National Academy of Sciences of the United States of America
volume
97
issue
12
pages
6850 - 6855
publisher
National Acad Sciences
external identifiers
  • scopus:12944252971
ISSN
0027-8424
DOI
10.1073/pnas.110035297
language
English
LU publication?
no
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6114e1da-c718-4e55-abb9-648fc92f132e
date added to LUP
2017-04-07 10:22:19
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2017-07-30 05:23:47
@article{6114e1da-c718-4e55-abb9-648fc92f132e,
  abstract     = {<p>The dopamine transporter (DAT) is a target of amphetamine (AMPH) and cocaine. These psychostimulants attenuate DAT clearance efficiency, thereby increasing synaptic dopamine (DA) levels. Re-uptake rate is determined by the number of functional transporters at the cell surface as well as by their turnover rate. Here, we present evidence that DAT substrates, including AMPH and DA, cause internalization of human DAT, thereby reducing transport capacity. Acute treatment with AMPH reduced the maximal rate of [<sup>3</sup>H]DA uptake, decreased AMPH-induced currents, and significantly redistributed the immunofluorescence of an epitope-tagged DAT from the plasma membrane to the cytosol in human embryonic kidney 293 cells. Conversely, DAT inhibitors, such as cocaine, mazindol, and nomifensine, when administered with AMPH, blocked the reduction in [<sup>3</sup>H]DA uptake and the redistribution of DAT immunofluorescence to the cytosol. The reductions of [<sup>3</sup>H]DA uptake and AMPH- induced DAT internalization also were inhibited by coexpression of a dominant negative mutant of dynamin I (K44A), indicating that endocytosis modulates transport capacity, likely through a clathrin-mediated pathway. With this mechanism of regulation, acute application of AMPH would reduce DA uptake not only by direct competition for uptake, but also by reducing the available cell-surface DAT. Moreover, AMPH-induced internalization might diminish the amount of DAT available for DA efflux, thereby modulating the cytotoxic effects of elevated extracellular DA.</p>},
  author       = {Saunders, Christine and Ferrer, Jasmine V. and Shi, Lei and Chen, Jiayun and Merrill, Gerald and Lamb, Maria E and Leeb-Lundberg, Fredrik and Carvelli, Lucia and Javitch, Jonathan A. and Galli, Aurelio},
  issn         = {0027-8424},
  language     = {eng},
  month        = {06},
  number       = {12},
  pages        = {6850--6855},
  publisher    = {National Acad Sciences},
  series       = {Proceedings of the National Academy of Sciences of the United States of America},
  title        = {Amphetamine-induced loss of human dopamine transporter activity : An internalization-dependent and cocaine-sensitive mechanism},
  url          = {http://dx.doi.org/10.1073/pnas.110035297},
  volume       = {97},
  year         = {2000},
}