Trace Amine-Associated Receptors (TAARs), discovered twenty years ago, have led to the identification of new treatments for neuropsychiatric disorders. An important fact was that shortly after the discovery of the receptors, a line of transgenic animals with a knockout of the TAAR1 receptor gene was created. The data obtained with the help of transgenic animals made it possible to understand not only the function of receptors, but also the mechanisms of action of psychotropic substances, the interactions of neurotransmitters with trace amines and pathological mechanisms in which trace amines play an important role. This brief review will examine the functions of trace amine receptors and the role of transgenic animals in their study.