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Neuroprotection afforded by adenosine A 2A receptor blockade is modulated by corticotrophin‐releasing factor ( CRF ) in glutamate injured cortical neurons
Author(s) -
Valadas Jorge S.,
Batalha Vânia L.,
Ferreira Diana G.,
Gomes Rui,
Coelho Joana E.,
Sebastião Ana M.,
Diógenes Maria José,
Lopes Luísa V.
Publication year - 2012
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/jnc.12050
Subject(s) - neuroprotection , glutamate receptor , blockade , neuroscience , adenosine , chemistry , receptor , medicine , endocrinology , biology
In situations of hypoxia, glutamate excitotoxicity induces neuronal death. The release of extracellular adenosine is also triggered and is accompanied by an increase of the stress mediator, corticotrophin‐releasing factor ( CRF ). Adenosine A 2A receptors contribute to glutamate excitoxicity and their blockade is effective in stress‐induced neuronal deficits, but the involvement of CRF on this effect was never explored. We now evaluated the interaction between A 2A and CRF receptors ( CRFR ) function, upon glutamate insult. Primary rat cortical neuronal cultures (9 days in vitro ) expressing both CRF 1 R and CRF 2 R were challenged with glutamate (20–1000 μM, 24 h). CRF 1 R was found to co‐localize with neuronal markers and CRF 2 R to be present in both neuronal and glial cells. The effects of the CRF and A 2A receptors ligands on cell viability were measured using propidium iodide and Syto‐13 fluorescence staining. Glutamate decreased cell viability in a concentration‐dependent manner. Urocortin (10 pM), an agonist of CRF receptors, increased cell survival in the presence of glutamate. This neuroprotective effect was abolished by blocking either CRF 1 R or CRF 2 R with antalarmin (10 nM) or anti‐Sauvagine‐30 (10 nM), respectively. The blockade of A 2A receptors with a selective antagonist SCH 58261 (50 nM) improved cell viability against the glutamate insult. This effect was dependent on CRF 2 R, but not on CRF 1 R activation. Overall, these data show a protective role of CRF in cortical neurons, against glutamate‐induced death. The neuroprotection achieved by A 2A receptors blockade requires CRF 2 R activation. This interaction between the adenosine and CRF receptors can explain the beneficial effects of using A 2A receptor antagonists against stress‐induced noxious effects.