Figure 3.

 Response to prostaglandin E₂ (PGE₂) in all cyclooxygenase (COX) mouse genotypes. Results were compiled from confocal measurements of extracellular pH (Cl-NERF ratio images) during continuous superfusion (0.2 ml/min) of the gastric mucosa, as described in the methods. pH was measured at various distances tangential to the mucosal surface 10–15 minutes after administration of exogenous dimethyl-PGE₂ in mice derived from COX-1 (A) and COX-2 (B) knockout colonies (+, wild-type; −, mutated allele). Values are mean (SEM), n = 3–6 per genotype.