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## Re: P22 PHOTOSENSITIZED MEMBRANE DAMAGE From: Lars Kunz and Günther Stark (gunther.stark@uni-konstanz.de) Date: 11/25/97 Time: 3:24:39 PM Remote Name: 134.34.3.27 ### Comments 1)The discrimination between a conductance increase of the membrane and a decrease of the seal resistance is difficult indeed. We think, however, that our interpretation is supported by the following experiment in the cell-attached configuration: If the dye was added to the pipette solution only, illumination was found to induce a transition from the cell-attached state to the (perforated patch-like) whole-cell configuration. This indicates an increase of the conductance of the membrane patch under the pipette. 2)Relative values for photodynamically induced Na+ and Cl- permeabilities were estimated from the value of the open circuit potential observed at different NaCl concentrations on both sides of the membrane. The relative permeabilities for different anions were obtained from potential measurements performed with Cl- on one side and the respective anion on the other side of the membrane (with Na+ as counter ion in both cases). Back to the list of comments