Modulation by Trace Amine-Associated Receptor 1 of Experimental Parkinsonism, L-DOPA Responsivity, and Glutamatergic Neurotransmission
The Journal of Neuroscience, October 14, 2015 • 35(41):14057–14069 • 14057 Neurobiology of Disease Modulation by Trace Amine-Associated Receptor 1 of Experimental Parkinsonism, L-DOPA Responsivity, and Glutamatergic Neurotransmission Alexandra Alvarsson,1* Xiaoqun Zhang,1* Tiberiu L Stan,1 Nicoletta Schintu,1 Banafsheh Kadkhodaei,2 Mark J. Millan,3 Thomas Perlmann,2,4 and Per Svenningsson1 1Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska Institutet, SE-17176 Stockholm, Sweden, 2Ludwig Institute for Cancer Research, SE-17177 Stockholm, Sweden, 3Pole of Innovation in Neuropsychiatry, Institut de Recherches Servier, Centre de Recherches de Croissy, Paris 87290, France, and 4Department of Cell and Molecular Biology, Karolinska Institutet, SE-17177 Stockholm, Sweden Parkinson’s disease (PD) is a movement disorder characterized by a progressive loss of nigrostriatal dopaminergic neurons. Restoration of dopamine transmission by L-DOPA relieves symptoms of PD but causes dyskinesia. Trace Amine-Associated Receptor 1 (TAAR1) modulates dopaminergic transmission, but its role in experimental Parkinsonism and L-DOPA responses has been neglected. Here, we report that TAAR1 knock-out (KO) mice show a reduced loss of dopaminergic markers in response to intrastriatal 6-OHDA administra- tion compared with wild-type (WT) littermates. In contrast, the TAAR1 agonist RO5166017 aggravated degeneration induced by intra- striatal6-OHDAinWTmice.Subchronic L-DOPAtreatmentofTAAR1KOmiceunilaterallylesionedwith6-OHDAinthemedialforebrain bundle resulted in more pronounced rotational behavior and dyskinesia than in their WT counterparts. The enhanced behavioral sensitization to L-DOPA in TAAR1 KO mice was paralleled by increased phosphorylation of striatal GluA1 subunits of AMPA receptors. Conversely, RO5166017 counteracted both L-DOPA-induced rotation and dyskinesia as well as AMPA receptor phosphorylation.
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