Adenosine A(2A) receptor interactions with receptors for other neurotransmitters and neuromodulators

Adenosine, by activating adenosine A(2A) receptors, seems to have a crucial function in regulating the activation of multiple receptors that affect ne urotransmitter release and/or synaptic transmission, in particular receptor s for neuropeptides (calcitonin gene related peptide (CGRP) and vasoactive intestinal peptide (VIP)), and NMDA receptors, metabotropic glutamate recep tors, nicotinic autofacilitatory receptors, dopamine receptors and adenosin e A(1) receptors. The manner in which these A(2A) receptors are involved in interactions with the receptors for other neurotransmitters and or neuromo dulators opens novel avenues for the action of this 'omnipresent' nucleosid e. Either by direct receptor-receptor modulation or by post-receptor mechan isms, adenosine, in its 'obsession' to protect cells from insults, uses as many receptor systems as possible to synchronize synaptic transmission, in order to exert what seems to be the 'destiny' of this nucleoside -protectio n of the nervous system. (C) 1999 Elsevier Science B.V. All rights reserved .