Received for publication January 4, 2007.
Revised July 6, 2007.
Accepted for publication July 6, 2007.

P2 receptor antagonist TNP-ATP protects hippocampus from oxygen and glucose deprivation cell death

Abstract

In this work we mainly used the organotypic model of rat hippocampus to demonstrate the protective role of the P2 receptor antagonist trinitrophenyl-adenosine-triphosphate (TNP-ATP) during oxygen/glucose deprivation. Among the P2X receptors that TNP-ATP specifically blocks, mainly P2X₁ seems to be involved in the processes of cell damage after oxygen/glucose deprivation. P2X₁ receptor is strongly and transiently upregulated in 24 hours after an ischemic insult, on structures likely corresponding to mossy fibers and Schaffer collaterals of CA1-3 and dentate gyrus and, furthermore, it is downregulated by pharmacological treatment with TNP-ATP, which is moreover found neuroprotective against ischemic cell death. Morphological studies conducted through immunofluorescence and confocal analysis in primary organotypic, in dissociated cultures, and in adult rat in vivo, finally demonstrated the neuronal colocalization of P2X₁ protein with neurofilament light chain and NeuN immunoreactivity in myelinated and unmyelinated fibers of both granular and pyramidal neurons. In conclusion, with this work we proved the neuronal distribution of P2X₁ receptor in hippocampus and presented evidences for a potential disadvantageous role of its expression during the path of in vitro ischemia.

Key words: metabolism impairment, neuronal fibers, neuroprotection, organotypic cultures, purinergic antagonist, pyramidal and granular neurons