3-iodothyronamine, a new chapter in thyroid story: implications in learning processes

Trace amines (TAs) are primary amines structurally related to classic monoamines derived from aminoacid metabolism. Their fast rate of degradation and/or inability to accumulate in substantial concentrations in synaptic vesicles determines their presence in trace in brain tissues. The role of TAs in mammalian physiology remains less well defined. The identification of targets for TAs, namely trace amine associated receptors (TAARs) raised the interest around the physiopathological role of TAs in neurodegenerative diseases. Thyroid hormone metabolism produces a series of primary amines, namely thyronamines, at different degree of iodination, including 3-iodothyronamine (T1AM). From that is known, T1AM presents some, but not all, the requisites to be defined as a TA. In fact, T1AM recognizes TAARs but its ubiquitous degradation does not exhaust its signaling activity. Interestingly, T1AM is endowed of pro-learning and anti-amnesic features revealing the existence of novel endogenous players in the relation between the thyroid and brain functions.