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 administration compared with wild-type (WT) littermates. In contrast, the TAAR1 agonist RO5166017 aggravated degeneration induced by intrastriatal6-OHD Ain WT mice. Subchronic L-DOPAtreatment ofTAAR1KOmice unilaterally lesioned with6-OHDAin the medial forebrain 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. Underpinning a role for TAAR1 receptors in modulating glutamate neurotransmission, intrastriatal application of RO5166017 prevented the increase of evoked corticostriatal glutamate release provoked by dopamine deficiency after 6-OHDA-lesions or conditional KO of Nurr1. Finally, inhibition of corticostriatal glutamate release by TAAR1 showed mechanistic similarities to that effected by activation of dopamineD2 receptors. These data unveil a role for TAAR1 in modulating the degeneration of dopaminergic neurons, the behavioral response to L-DOPA, and presynaptic and postsynaptic glutamate neurotransmission in the striatum, supporting their relevance to the pathophysiology and, potentially, management of PD.
CITATION STYLE
Alvarsson, A., Zhang, X., Stan, T. L., Schintu, N., Kadkhodaei, B., Millan, M. J., … Svenningsson, P. (2015). Modulation by trace amine-associated receptor 1 of experimental parkinsonism, L-DOPA responsivity, and glutamatergic neurotransmission. Journal of Neuroscience, 35(41), 14057–14069. https://doi.org/10.1523/JNEUROSCI.1312-15.2015
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