title: Synaptic P2X7 and oxygen/glucose deprivation in organotypic hippocampal cultures.
abstract: The P2X7 receptor for extracellular ATP is the main candidate, among P2 receptors, inducing cell death in the immune system. Here, we demonstrate the direct participation of this receptor to cell damage induced by oxygen/glucose deprivation, in the ex vivo model of organotypic hippocampal cultures. By pharmacological and immunological approaches, we show that P2X7 is rapidly and transiently up regulated in hippocampal areas eliciting metabolism impairment. Moreover, the P2 antagonists 2',3',-dialdehyde ATP and reactive blue 2 prevent both up regulation of this receptor and hypoxic/hypoglycemic damage. By confocal laser microscopy, we show that P2X7 is present at the synaptic level of fibers extending from the CA1-2 pyramidal cell layer throughout the strata oriens and radiatum, but absent on oligodendrocytes, astrocytes or neuronal cell bodies. Colocalization of P2X7 is obtained with neurofilament-L protein and with synaptophysin, not with myelin basic protein, glial fibrillary acidic protein or a marker for neuronal nuclei. P2X7 up regulation and diffuse cellular damage are also induced by 3'-O-(4-benzoyl) benzoyl-ATP, an agonist selective but not exclusive for P2X7. In summary, our study demonstrates that P2X7 not only directly participates to the hypoxic/hypoglycemic process, but also owns specific phenotypic localization. We do not exclude that it might serve as a sensor of dysregulated neuronal activity and ATP release, both occurring during oxygen/glucose deprivation.
authors.affiliation: Fondazione Santa Lucia, Rome, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Cavaliere
authors.forename: Susanna
authors.initials: S
authors.lastname: Amadio
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Sancesario
authors.forename: Giorgio
authors.initials: G
authors.lastname: Bernardi
authors.forename: Cinzia
authors.initials: C
authors.lastname: Volonté
mesh_terms: D000818:Animals; D015153:Blotting, Western; D016923:Cell Death; D003470:Culture Media; D005947:Glucose / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism* / Q000473:pathology; D018613:Microscopy, Confocal; D009924:Organ Culture Techniques; D010100:Oxygen / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D018048:Receptors, Purinergic P2 / Q000096:biosynthesis*; D058486:Receptors, Purinergic P2X7; D015854:Up-Regulation
chemical_list: D003470:Culture Media; D018048:Receptors, Purinergic P2; D058486:Receptors, Purinergic P2X7; D005947:Glucose; D010100:Oxygen