function:Orphan receptor. Ligands are likely small molecules, either sharing some similarities with trace amine as, e.g. derivatives of indolamines (such as 5-methoxytryptamine) or of phenylethylamines (such as phenylethanolamine) or being any kind of metabolite of amino acids or biogenic amine neurotransmitters.,similarity:Belongs to the G-protein coupled receptor 1 family.,tissue specificity:Expressed almost exclusively in skeletal muscle and selected areas of the brain, such amygdala, hippocampus, caudate nucleus, thalamus and hypothalamus. Weak expression is also find in substantia nigra.,