Adenosine A2A receptors and brain injury: broad spectrum of neuroprotection, multifaceted actions and "fine tuning" modulation.
This review summarizes recent developments that have contributed to understand how adenosine receptors, particularly A2A receptors, modulate brain injury in various animal models of neurological disorders, including Parkinson's disease (PD), stroke, Huntington's disease (HD), multiple sclerosis, Alzheimer's disease (AD) and HIV-associated dementia. It is clear that extracellular adenosine acting at adenosine receptors influences the functional outcome in a broad spectrum of brain injuries, indicating that A2A Rs may modulate some general cellular processes to affect neuronal cells death. Pharmacological, neurochemical and molecular/genetic approaches to the complex actions of A2A receptors in different cellular elements suggest that A2A receptor activation can be detrimental or protective after brain insults, depending on the nature of brain injury and associated pathological conditions. An interesting concept that emerges from these studies is A2A R's ability to fine tune neuronal and glial functions to produce neuroprotective effects. While the data presented here clearly highlight the complexity of using adenosinergic agents therapeutically in PD and other neurodegenerative disorders and point out many areas for further inquiry, they also confirm that adenosine receptor ligands, particularly A2A receptor ligands, have many promising characteristics that encourage the pursuit of their therapeutic potential.
Chen
Jiang-Fan
JF
Department of Neurology, Boston University School of Medicine, 715 Albany Street, C329, Boston, MA 02118, USA. chenjf@bu.edu
Sonsalla
Patricia K
PK
Pedata
Felicita
F
Melani
Alessia
A
Domenici
Maria Rosaria
MR
Popoli
Patrizia
P
Geiger
Jonathan
J
Lopes
Luísa V
LV
de Mendonça
Alexandre
A
D000241:Adenosine / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D001927:Brain Diseases / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism*; D020208:Brain Injury, Chronic / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D019610:Cytoprotection / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D009410:Nerve Degeneration / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D018696:Neuroprotective Agents / Q000494:pharmacology; D043705:Receptor, Adenosine A2A / Q000378:metabolism*
D018696:Neuroprotective Agents; D043705:Receptor, Adenosine A2A; D000241:Adenosine