Heterodimeric adenosine receptors: a device to regulate neurotransmitter release

Abstract.

Since 1990 it has been known that dimers are the basic functional form of nearly all G-protein-coupled receptors (GPCRs) and that homo- and heterodimerization may play a key role in correct receptor maturation and trafficking to the plasma membrane. Nevertheless, homo- and heterodimerization of GPCR has become a matter of debate especially in the search for the precise physiological meaning of this phenomenon. This article focuses on how heterodimerization of adenosine A₁ and A_2A receptors, which are coupled to apparently opposite signalling pathways, allows adenosine to exert a fine-tuning modulation of striatal glutamatergic neurotransmission, providing a switch mechanism by which low and high concentrations of adenosine inhibit and stimulate, respectively, glutamate release.