Lung inflammation caused by P2Y and P2X selective agonist. Hematoxilin-eosin staining of the lung 24 h after the instillation of UTP or α,β-MeATP. Infiltration of inflammatory cells, increased thickness of the alveolar walls and alveolar hemorrhages were observed in the 200 mM UTP-treated lungs. However, there was no evident derangement in the 200 mM α,β-MeATP-treated lungs. Bars = 100 μm in the upper panels, and = 50 μm in the lower panels. B. Immunohistochemistry of the P2Y2 and P2Y4 receptors. P2Y2 and P2Y4 receptors were detected in bronchiolar epithelial cells, alveolar walls and alveolar macrophages in the lung of untreated mice. Bars = 100 μm in the upper panels, and = 50 μm in the lower panels.