Role of P2X7 receptors in release of glutamate and γ-aminobutyric acid during oxygen-glucose deprivation in rat hippocampus and neuronal synaptosome / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the role of P2X7 receptors in release of glutamate (Glu) and γ-aminobutyric acid (GABA) during oxygen-glucose deprivation (OGD) in rat hippocampus and neuronal synaptosome.Methods Healthy male SD rats weighing 150-200 g were decapitated. Their hippocampi were isolated and cut into slices 400 μm thick or made into neuronal synaptosomes. The hippocampal slices and neuronal synaptosomes were incubated in artificial cerebro-spinal fluid (aCSF) at 35℃ for 30 min and divided into 3 groups ( n = 32 or 24 each) control group (group C); group OGD and group OGD + BBG (brilliant blue G, a specific P2X7 receptor antagonist). OGD was induced by incubating the slices and synaptosomes in glucose-free aCSF aerated with 95% N2-5% CO2. In group OGD + BBG the slices and synaptosomes were incubated in O2-glucose deprived aCSF containing BBG 1 μmol/L 2 ml. Release of Glu and GABA from hippocampal slices and synaptosomes was determined by HPLC at 0, 20, 40, 60 min of OGD (T1-4). Hippocampal slices were examined with microscope.Results ( 1 ) The release of Glu and GABA from hippocampal slices and synaptosomes were significantly increased after OGD ( P ＜ 0.05). (2) Glu released from hippocampal slices was significantly decreased at T3-4 and Glu released from synaptosomes increased at T2-4 in group OGD + BBG as compared with group OGD ( P ＜ 0.05). (3)GABA released from hippocampal slices was significantly decreased at T4 in group OGD + BBG as compared with group OGD ( P ＜ 0.05). There was no significant difference in GABA released from synaptosomes between group OGD and OGD + BBG (P ＞ 0.05). (4) Microscopic examination showed that OGD induced significant histopathological damage to hippocampal slices which was attenuated by BBG treatment. Conclusion P2X7 receptors mediates the release of Glu and GABA during OGD in rat hippocampus and the P2X7 receptors in glial cells plays a leading role.