Effects of EP agonists on the transepithelial electric resistance. Caco-2 cells were grown to confluence on Transwell polycarbonate filters and the TER was measured before and after treatment with agonists. All the agonists caused a drop of the TER at 15 and 30 min and at 60 and 120 min a recovery was observed. S.E.M of three independent experiments are shown. Significantly different: * (P < 0.05).