Immunoreactivity of a G protein-coupled L-DOPA receptor GPR143, in Lewy bodies

L-3,4-Dihydroxyphenylalanine (L-DOPA) has been believed to be an inert amino acid precursor of dopamine, and is the most effective therapeutic agent in Parkinson's disease (PD). We proposed L-DOPA as a neurotransmitter in the central nervous system. Recently, the ocular albinism 1 gene product, OA1/GPR143 (GPR143), was identified as a receptor for L-DOPA. In this study, we examined by generating anti-human GPR143 antibody, the localization of GPR143-immunoreactive signals in the brains from control and PD subjects. GPR143-immunoreactive signals were detected throughout the entire midbrain including substantia nigra pars compacta. In the PD brains, we found that GPR143-immunoreactive signals were detected in Lewy bodies and were colocalized with immunoreactive signals with anti-human Ser129 phosphorylated alpha-synuclein antibody. Although the significance of its occurrence in the inclusion bodies is unknown, our finding suggests possible implications of GPR143 in PD. (C) 2019 Elsevier B.V. and Japan Neuroscience Society. All rights reserved.