Fig. 7. Quantitative analysis of the effect of EP₃ receptor stimulation on the localization of AQP2 in IMCD cells in the presence of high levels of cAMP. IMCD cells were treated as indicated in Fig. 6. AQP2 immunofluorescence signals were detected by laser scanning microscopy and the ratios of intracellular/plasma membrane signal intensities were determined as described in the legend to Fig. 2 (n=20 cells for each condition tested; mean ± s.e.; three independent experiments). *, ** and #, values significantly different from AVP-, Bt₂cAMP- and forskolin-stimulated cells respectively (P<0.001).