Inhibition of ATP-Induced Glutamate Release by MRS2179 in Cultured Dorsal Spinal Cord Astrocytes

Abstract

It was reported that ATP, an excitatory chemical mediator, exerts its effects by activation of the P2X (ligand-gated cationic channels) and P2Y (G protein-coupled receptors) purinoceptors in the nervous system. In the present work, we used confocal laser scanning microscopy and high-performance liquid chromatography to assess the role of the P2Y₁ receptor in ATP-evoked Ca²⁺ mobilization and glutamate release from cultured dorsal spinal cord astrocytes. ATP (0.01–100 µmol/l) produces a dose-dependent rise in the Ca²⁺ relative fluorescence intensity in cultured astrocytes. N6methyl-2′-deoxyadenosine-3′,5′-bisphosphate (MRS2179, 0.01–100 µmol/l), a P2Y₁-specific antagonist, could dose-dependently inhibit ATP-evoked Ca²⁺ mobilization. In addition, 100 µmol/l ATP caused glutamate efflux from cultured dorsal spinal cord astrocytes in a time-dependent manner. 100 µmol/l MRS2179 significantly inhibited the glutamate efflux induced by ATP, which suggests that P2Y₁ receptor activation is responsible for the ATP-induced glutamate efflux from astrocytes. Taken together, our results demonstrate that P2Y₁ receptor plays an important role in modulating the function of astrocytes, which raises the possibility that MRS2179, a potent P2Y₁-specific antagonist, may become a potential drug in treating many chronic neurological diseases characterized by astrocytic activation in the nervous system.