Pharmacological characterization of the receptor involved in the protective effect of ODN on astroglial cells.

<p>(A) Cultured astrocytes were pre-incubated for 30 min in the absence or presence of ODN (0.1 nM), the metabotropic receptor agonist OP (0.1 nM), the inactive ODN analog [Ala¹⁵]ODN (0.1 nM) or the specific CBR agonist clonazepam (Clona; 10 nM), and then incubated for 1 h with medium alone or with 300 µM H₂O₂ without or with receptor ligands. (B) Cells were pre-incubated for 30 min in the absence or presence of the metabotropic receptor antagonist cyclo_1–8 [DLeu⁵] OP (c[DLeu⁵] OP; 1 µM) or the CBR antagonist flumazenil (1 µM), and then incubated for 1 h with medium alone or with 300 µM H₂O₂ without or with ODN (0.1 nM). Cell survival was quantified by measuring FDA fluorescence intensity, and the results are expressed as percentages of control. Each value is the mean (± SEM) of at least 12 different wells from three independent cultures. ANOVA followed by the Bonferroni's test. <i>*** p</i><0.001; NS, not statistically different <i>vs.</i> control. ^###<i>p</i><0.001; ns, not statistically different <i>vs.</i> H₂O₂-treated cells.