title: Amphetamine action at the cocaine- and antidepressant-sensitive serotonin transporter is modulated by αCaMKII.
abstract: Serotonergic neurotransmission is terminated by reuptake of extracellular serotonin (5-HT) by the high-affinity serotonin transporter (SERT). Selective 5-HT reuptake inhibitors (SSRIs) such as fluoxetine or escitalopram inhibit SERT and are currently the principal treatment for depression and anxiety disorders. In addition, SERT is a major molecular target for psychostimulants such as cocaine and amphetamines. Amphetamine-induced transport reversal at the closely related dopamine transporter (DAT) has been shown previously to be contingent upon modulation by calmodulin kinase IIα (αCaMKII). Here, we show that not only DAT, but also SERT, is regulated by αCaMKII. Inhibition of αCaMKII activity markedly decreased amphetamine-triggered SERT-mediated substrate efflux in both cells coexpressing SERT and αCaMKII and brain tissue preparations. The interaction between SERT and αCaMKII was verified using biochemical assays and FRET analysis and colocalization of the two molecules was confirmed in primary serotonergic neurons in culture. Moreover, we found that genetic deletion of αCaMKII impaired the locomotor response of mice to 3,4-methylenedioxymethamphetamine (also known as "ecstasy") and blunted d-fenfluramine-induced prolactin release, substantiating the importance of αCaMKII modulation for amphetamine action at SERT in vivo as well. SERT-mediated substrate uptake was neither affected by inhibition of nor genetic deficiency in αCaMKII. This finding supports the concept that uptake and efflux at monoamine transporters are asymmetric processes that can be targeted separately. Ultimately, this may provide a molecular mechanism for putative drug developments to treat amphetamine addiction.
authors.affiliation: Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Steinkellner
authors.affiliation: Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria.; 2UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: Therese R
authors.initials: TR
authors.lastname: Montgomery
authors.affiliation: Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria.
authors.forename: Tina
authors.initials: T
authors.lastname: Hofmaier
authors.affiliation: Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria.
authors.forename: Oliver
authors.initials: O
authors.lastname: Kudlacek
authors.affiliation: Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria.
authors.forename: Jae-Won
authors.initials: JW
authors.lastname: Yang
authors.affiliation: Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Denmark.
authors.forename: Mattias
authors.initials: M
authors.lastname: Rickhag
authors.affiliation: Department of Pediatrics, Medical University of Vienna, 1090 Vienna, Austria,
authors.forename: Gangsoo
authors.initials: G
authors.lastname: Jung
authors.affiliation: Department of Pediatrics, Medical University of Vienna, 1090 Vienna, Austria,
authors.forename: Gert
authors.initials: G
authors.lastname: Lubec
authors.affiliation: Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Denmark.
authors.forename: Ulrik
authors.initials: U
authors.lastname: Gether
authors.affiliation: Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Freissmuth
authors.affiliation: Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria; Center for Addiction Research and Science, Medical University of Vienna, 1090 Vienna, Austria.
authors.forename: Harald H
authors.identifier: http://orcid.org/0000-0002-1339-7444
authors.initials: HH
authors.lastname: Sitte
mesh_terms: D000661:Amphetamine / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D000928:Antidepressive Agents / Q000378:metabolism / Q000494:pharmacology*; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000502:physiology*; D002478:Cells, Cultured; D003042:Cocaine / Q000378:metabolism / Q000494:pharmacology*; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D017207:Rats, Sprague-Dawley; D050486:Serotonin Plasma Membrane Transport Proteins / Q000378:metabolism*
chemical_list: D000928:Antidepressive Agents; D050486:Serotonin Plasma Membrane Transport Proteins; C493231:Slc6a4 protein, mouse; D000661:Amphetamine; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; C517671:Camk2a protein, mouse; D003042:Cocaine
keywords: addiction; amphetamines; monoamine transporters; reverse transport; serotonin