GPR61 is a G protein-coupled receptor that is closely related to biogenic amine receptors. It has wide expression throughout the central nervous system, where it is thought to play an important role in numerous phsyiological functions. It is thought to be involved in the cAMP, inositol phosphate and Beta-arrestin pathways, and has regulatory interaction with MT2 receptors. In immunohistochemistry, GPR61 has membranous and cytoplasmic positivity in the central nervous system, and is also found in the eye, in the pituitary gland and in other endocrine tissues. References: J Neurosci Res. 2009 May 1;87(6):1329-33, PMID: 19025769; Sci Rep. 2017 Aug 21;7(1):8990, PMID: 28827538