Olfactory receptor specific for trimethylamine, a trace amine enriched in the urine of male mice, playing a role in social behavior. Trimethylamine is present at high concentration in the urine of male mice after puberty and acts as an attractant. This receptor is probably mediated by the G(s)-class of G-proteins which activate adenylate cyclase. Specifically expressed in neurons of the olfactory epithelium, to discrete glomeruli predominantly localized to a confined bulb region. Present in the dorsal area of the main olfactory epithelium. Mice lacking Taar2, Taar3, Taar4, Taar5, Taar6, Taar7a, Taar7b, Taar7d, Taar7e, Taar7f, Taar8a, Taar8b, Taar8c and Taar9 show no visible phenotype or behavioral deficits. They however show an absence of aversion to low concentrations of amines such as 2-phenylethylamine, isopentylamine, N-methylpiperidine and cadaverine. Trimethylamine is a bacterial metabolite found in some animal odors, and is a repulsive odor associated with bad breath and spoiled food for most organisms, except for M.musculus, where it acts as an attractant (PubMed:16878137, PubMed:23177478). Belongs to the G-protein coupled receptor 1 family.