A, effects of the EGF receptor tyrosine kinase inhibitor tyrphostin B46 (50 μm) and the PDGF receptor tyrosine kinase inhibitor tyrphostin AG1296 (50 μm) on whole-cell VSOR Cl− currents recorded at +40 mV in swollen control (upper panel) and BPV cells (lower panel). B, summary of these effects. The current densities were normalised to the control values recorded before application of tyrphostin B46 or AG1296. * Significantly different from the control values. C, concentration–response curves for tyrphostin B46 effects in control (○, n = 4–5) and BPV cells (•, n = 4–5). Curves represent logistic non-linear curve fits. The IC50 and Hill coefficient were 31.7 ± 3.7 μm and 1.3 ± 0.2, respectively, in control cells and 12.0 ± 0.9 μm and 1.0 ± 0.1, respectively, in BPV cells.