The relationship between the resistance of a membrane patch and predicted changes in total patch circuit resistance...

The objective of this study was to determine the relationship between the magnitude of the membrane resistance in the free area of a cell-attached patch-clamp recording and the change in total patch circuit resistance that would be produced by the introduction of a series resistance, such as would be observed upon acquiring a patch-clamped membrane vesicle. The results describe a method for determining the magnitude of the membrane resistance in the free area of a membrane patch, and demonstrate that: (a) at a given value of shunt resistance, areas of membrane with higher resistivity produce smaller proportional increases in total patch circuit resistance upon acquiring a membrane vesicle; and (b) a presumption of spherical vesicle formation provides a lower limit estimate of the membrane resistance. The described procedures and relationships are useful in developing new techniques for examining channel activity in membrane patches where individual events are below the present limits of detection, for examining changes in membrane resistivity and/or shunt resistance in patches undergoing cytoskeletal re-organization, and for assessing the potential influence of series resistance changes on single channel parameters in longer term cell-attached patch-clamp recordings.