Fig. 3.

Blockade of P2 receptors on astrocytes downregulates induction of TNFα, IL-6, and nitrite production. Astrocytes were pretreated with varying doses of oATP (0, 300, or 30 μm) for 2 hr, washed, and exposed to IL-1β(10 ng/ml) or IL-1β plus IFNγ (200 U/ml) as indicated. Control cultures (con) consisted of astrocytes treated with oATP alone (300 μm) without cytokines. TNFα (B) and IL-6 (C) levels in the supernatant were determined at 16 hr and nitrite (A) at 48 hr. Pretreatment with oATP resulted in a dose-dependent inhibition of nitrite, TNFα, and IL-6 after stimulation with IL-1β alone or in combination with IFNγ. Note also that, whereas IFNγ potently synergized with IL-1β for nitrite and TNFα production, it had little effect on IL-6 expression. *p < 0.05 indicates statistically significant reduction compared with cytokine stimulation without inhibitors. Data represent the mean and SD of results from three different wells and are representative of cells derived from three different brains.