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The mechanism of amphetamine‐mediated trafficking of the dopamine transporter (1145.1)
Author(s) -
Underhill Suzanne,
Thiels Edda,
Amara Susan
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.1145.1
Subject(s) - internalization , rhoa , dopamine transporter , amphetamine , dopamine , microbiology and biotechnology , dopamine plasma membrane transport proteins , intracellular , chemistry , signal transduction , biology , receptor , neuroscience , dopaminergic , biochemistry
Acute amphetamine (AMPH) exposure elevates extracellular dopamine by a variety of mechanisms including increasing the rate of internalization of the plasma membrane dopamine transporter (DAT). We report here that AMPH also activates the small GTPases, Rho and Rac. In recombinant expression systems, primary cultures and midbrain slices, activation of Rho and the downstream Rho‐kinase (ROCK) triggers endocytosis of DAT. Inhibition of RhoA activity blocks AMPH‐induced DAT internalization, while Rac1 inhibition has no significant effect on DAT trafficking. ROCK inhibitors also prevent AMPH‐induced DAT internalization. Intriguingly, we found that AMPH must enter the cell to initiate this cascade. Further, intracellular AMPH also increases cAMP, leading to the phosphorylation of Rho by protein kinase A (PKA) that inactivates Rho and serves as a break on DAT internalization, thus demonstrating an important interaction between PKA‐ and RhoA‐dependent signaling in mediating the actions of AMPH. In agreement with our observations in cell lines and brain slices, we have also shown that the activation of receptors that couple to PKA in dopamine neurons within the brain can antagonize the behavioral effects of AMPH in mice. These observations imply the existence of a novel intracellular target that mediates the effects of AMPH on Rho and cAMP signaling and suggest new pathways to target in order to disrupt AMPH action. Grant Funding Source : Supported by the National Institute of Mental Health Intramural Program.