Trace amine-associated receptor 1 (TAAR1) is a protein that in humans is encoded by the TAAR1 gene. TAAR1 is an amine-activated G_s- and  G protein-coupled receptor (GPCR) that is located in several peripheral organs and circulating lymphocytes, as well as in astrocytes and within the presynaptic plasma membrane (i.e., axon terminal) of monoamine neurons in the central nervous system (CNS). TAAR1 was discovered in 2001 by two independent groups of investigators, Borowski et al. and Bunzow et al. TAAR1 is one of six functional trace amine-associated receptors in humans, which are so named for their ability to bind endogenous amines that occur in tissues at trace concentrations. TAAR1 plays a significant role in regulating neurotransmission in dopamine, norepinephrine, and serotonin neurons in the CNS; it also affects immune system and neuroimmune system function through different mechanisms.