Fig. 2

Effects of polyethylene glycols on the single CFTR Cl⁻ channel currents. Representative current traces recorded from excised inside-out patches at +60 and at −60 mV in control conditions in the absence of nonelectrolytes (a) and in the presence of PEG 300 (b) and PEG 2,000 (c) in the bath solution. C denotes the closed state, O corresponds to the open channel level, respectively. The respective all-point histograms are shown at the right of each record; the histograms (shadowed) were fitted with Gaussians (solid lines) to give the peak-to-peak single-channel amplitudes (i) as indicated. Single-channel current–voltage relationships (d) were obtained in control conditions (filled circles) and in the presence of PEG 300 (open circles) and PEG 2,000 (open triangles) in the bath solution. Each data point represents the mean ± SEM of 5–29 measurements from 5–9 patches. Solid lines are linear fits with slopes corresponding to the unitary outward and inward conductances given in the text. The slope for PEG 300 is significantly different from the control slope at P < 0.05