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. 2006 Jun 5;103(24):9321–9326. doi: 10.1073/pnas.0603146103

Fig. 2.

Fig. 2.

ATP-induced TSP-1 expression is mediated by purinergic receptors. Astrocytes were treated with P2 antagonists (RB2 or PPADS; 50 μM; 15 min) or a P1 antagonist [8-(p-sulfophenyl)-theophylline; (8-PSPT); 10 μM; 15 min] before addition of ATP (100 μM; 6 h). (A) Immunoblotting shows that RB2, PPADS, or 8-(p-sulfophenyl)-theophylline decreased the expression of TSP-1 induced by ATP. GRB-2 is a loading control. The bar graph shows fold stimulation of TSP-1 protein levels compared with ATP-treated cultures after antagonist treatment (∗, P < 0.05; ∗∗∗, P < 0.001; n = 8). (B) Immunocytochemistry of cultured rat astrocytes after apyrase and ATP treatment. Astrocytes were treated with apyrase (90 units; 15 min), an ATP diphosphohydrolase that metabolizes ATP to AMP, before addition of 100 μM ATP for 6 h. Apyrase-treated cultures exhibited weak TSP-1 immunoreactivity (d) when compared with ATP-treated cultures (b). In addition, apyrase-treated cultures also showed weak GFAP immunoreactivity (c) when compared with ATP-treated cultures (a). Corresponding images in left and right panels are from the same fields. Red, TSP-1; green, GFAP; blue, DAPI. (Scale bar: 50 μm.)