Figure 4.

Effect of AH23848B on PGE₂-induced cyclic AMP formation by tracheal epithelial cells. Cells were pre-incubated for 15 min with rolipram (10 μM) plus (A) AH23848B (10 μM (open triangles) or 100 μM (solid triangles)) or medium only (open circles), or (B) AH22921X (10 μM (solid diamonds), 50 μM (open triangles) or 100 μM (solid triangles)) or medium only (open circles) and then incubated for a further 15 min with increasing concentrations of PGE₂ (A and B). The conversion of [³H]-ATP to [³H]-cyclic AMP was assayed as described in Methods. The points represents the mean±s.e.mean of four determinations made with separate cell preparations.