THE RELATIONSHIP BETWEEN THE RESISTANCE OF A MEMBRANE PATCH AND PREDICTED CHANGES IN TOTAL PATCH CIRCUIT RESISTANCE SECONDARY TO SPONTANEOUS OR INDUCED ALTERATIONS IN PATCH GEOMETRY

The objective of this study was to determine the relationship between the magnitude of the membrane resistance in the free area of a cell-at tached patch-clamp recording and the change in total patch circuit res istance that would be produced by the introduction of a series resista nce, 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 d emonstrate that: (a) at a given value of shunt resistance, areas of me mbrane with higher resistivity produce smaller proportional increases in total patch circuit resistance upon acquiring a membrane vesicle; a nd (b) a presumption of spherical vesicle formation provides a lower l imit estimate of the membrane resistance. The described procedures and relationships are useful in developing new techniques for examining c hannel activity in membrane patches where individual events are below the present limits of detection, for examining changes in membrane res istivity and/or shunt resistance in patches undergoing cytoskeletal re -organization, and for assessing the potential influence of series res istance changes on single channel parameters in longer term cell-attac hed patch-clamp recordings.