title: Potential therapeutic relevance of adenosine A2B and A2A receptors in the central nervous system.
abstract: Adenosine A2B and, much more importantly, adenosine A2A receptors modulate many physiological and pathological processes in the brain. In this review, the most recent evidence concerning the role of such receptors and their potential therapeutic relevance is discussed. The low affinity of A2B receptors for adenosine implies that they might represent a good therapeutic target, since they are activated only under pathological conditions (when adenosine levels raise up to micromolar concentrations). The availability of selective ligands for A2B receptors would allow exploration of such an hypothesis. Since adenosine A2A receptors mediate both potentially neuroprotective and potentially neurotoxic effects, their role in neurodegenerative diseases is highly controversial. Nevertheless, A2A receptor antagonists have shown clear antiparkinsonian effects, and a great interest exists on the role of A2A receptors in Alzheimer's disease, brain ischaemia, spinal cord injury, drug addiction and other conditions. In order to establish whether such receptors represent a target for CNS diseases, at least two conditions are needed: the full comprehension of A2A-dependent mechanisms and the availability of ligands capable of discriminating among the different receptor populations.
authors.affiliation: Department of Therapeutic Research and Medicines Evaluation, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Roma, Italy. patrizia.popoli@iss.it
authors.forename: Patrizia
authors.initials: P
authors.lastname: Popoli
authors.forename: Rita
authors.initials: R
authors.lastname: Pepponi
mesh_terms: D058917:Adenosine A2 Receptor Antagonists / Q000627:therapeutic use*; D002490:Central Nervous System / Q000378:metabolism*; D006801:Humans; D058990:Molecular Targeted Therapy / Q000379:methods; D019636:Neurodegenerative Diseases / Q000188:drug therapy*; D018696:Neuroprotective Agents / Q000627:therapeutic use*; D043705:Receptor, Adenosine A2A / Q000378:metabolism*; D043704:Receptor, Adenosine A2B / Q000378:metabolism*
chemical_list: D058917:Adenosine A2 Receptor Antagonists; D018696:Neuroprotective Agents; D043705:Receptor, Adenosine A2A; D043704:Receptor, Adenosine A2B