Olfactory receptor specific for trimethylamine, a trace amine. Also activated at lower level by dimethylethylamine. Trimethylamine is a bacterial metabolite found in some animal odors, and to humans it is a repulsive odor associated with bad breath and spoiled food. This receptor is probably mediated by the G(s)-class of G-proteins which activate adenylate cyclase. 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. Polymorphic variants of this gene are not associated with specific anosmia for trimethylamine. Belongs to the G-protein coupled receptor 1 family.