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The Yin and Yan of Adenosine A 1 and A 2A Receptors in Global Cerebral Ischemia Reperfusion Injury
Author(s) -
Atef Reham,
Agha Azza,
Nassar Noha
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.1026.9
Subject(s) - neuroprotection , glutamate receptor , chemistry , pharmacology , adenosine , agonist , adenosine receptor , medicine , endocrinology , neuroscience , anesthesia , receptor , biology , biochemistry
Global cerebral ischemia reperfusion (IR) following cardiac arrest, shock and asphyxia can affect wide brain areas where new therapies are imperative. Moreover, many intracellular pathways mediating tissue response to IR are still elusive. Adenosine is a neuromodulator that greatly impacts IR through the inhibitory A 1 and excitatory A 2 receptors. Studies indicate that both adenosine A 1 agonists and A 2A antagonists are neuroprotective during ischemic insults. However, many of the signaling pathways affecting such responses are largely unknown. In the current study, bilateral carotid occlusion for 45 min. followed by 24h reperfusion period resulted in histopathological damage as well as memory impairment, motor incoordination and increased locomotor activity. Such events were attenuated by unilateral intra‐hippocampal injection of both the selective A 1 agonist N6‐cyclohexyl adenosine (CHA) and the A 2A antagonist 7‐(2‐phenylethyl)‐5‐amino‐2‐(2‐furyl)‐pyrazolo‐[4,3‐e]‐1,2,4‐triazolo[1,5‐c]pyrimidine (SCH58261). On the cellular level, IR increased glutamate, pERK1/2, c‐Fos, NF‐ k B, TNF‐α, cytochrome c, caspase‐3, BDNF, Nrf2 and IL‐10 contents. Both CHA and SCH58261signifiantly reduced glutamate, c‐Fos, TNF‐α, cytochrome c, caspase‐3 and increased Nrf‐2 and IL‐10 contents. While only SCH58261 reduced pERK1/2, NF‐ k B and BDNF contents. By the same token, iNOS and TBARS levels were increased following IR and attenuated by both CHA and SCH58261 treatments. Accordingly, these results lend insight to the neuroprotective effects of A 1 and A 2A agonists and antagonists respectively where pERK1/2 and NF‐ k B pathways might be involved in adenosine mediated attenuation of inflammation, apoptosis and oxidative stress.