Trace amines as bona fide neurotransmitters in mammalian CNS

Abstract

A new family of G-protein-coupled receptors (GPCR) for ‘trace amines’ has been cloned from human and rat brain. Tyramine, β-phenylethylamine, tryptamine and octopamine are neurotransmitters in invertebrate nervous systems but exist in trace amounts in vertebrates and are therefore usually referred to as ‘false transmitters’ in the mammalian counterpart. A new report, however, identifies a new class of GPCRs similar to that of classical bioamines such as noradrenaline, dopamine or seratonin, which binds to and is activated by trace amines in human and rat brain. The study describes the localization of these receptors in the brain amygdala, lending support to the postulated role for trace amines in the etiology of emotional disorders. In fact, human trace amine receptor genes are shown to map to chromosome 6q23.2, in close proximity to a susceptibility locus for schizophrenia, thus indicating that further research on the role of these receptors in the etiology of this disease is of crucial importance. Proc. Natl. Acad. Sci. U. S. A. 98, 8966–8971. SS