Cardiac effects of thyronamines.

3-Iodothyronamine (T(1)AM) is an endogenous compound derived from thyroid hormone through decarboxylation and deiodination, which interacts with a novel G protein-coupled receptor, known as trace amine-associated receptor 1 (TAAR1). TAAR1 and other receptors of this family are expressed in several tissues, including the heart. Functional effects have been observed after administration of exogenous T(1)AM: in the isolated heart, a negative inotropic and chronotropic action was produced, and the resistance to ischemic injury was increased, possibly as a consequence of an action on intracellular calcium homeostasis. Extracardiac effects include reduction of body temperature, increased lipid versus carbohydrate metabolism, and modulation of insulin secretion. T(1)AM might play an important physiological or pathophysiological role, and this signaling system might allow the development of new therapeutical agents.