GPR37 and Parkinson disease: GPR37 can be found in pre-myelinating/myelinating oligodendrocytes, dopaminergic neurons, and hippocampal neurons.475 GPR37 shares high sequence homology with peptide-activated GPCRs such as endothelin receptor B (ETB).475 In Parkinson’s disease, GPR37 acts as an adenosine A2A receptor inhibitor via receptor oligomerization;476 GPR37L1, in contrast, is found mainly in astrocytes and oligodendrocyte progenitor cells.475 GPR37L1 is involved in the adaptive myelination of oligodendrocytes which is critical for neural plasticity, learning, and memory in adults.477