The interpretation of current-clamp recordings in the cell-attached patch-clamp configuration.
In these experiments we have investigated the feasibility and accuracy of recording steady-state and dynamic changes in transmembrane potential noninvasively across an intact cell-attached patch using the current-clamp mode of a conventional patch-clamp amplifier. Using an equivalent circuit mimicking simultaneous whole-cell voltage-clamp and cell-attached current-clamp recordings we have defined both mathematically and experimentally the relationship between the membrane patch resistance, the seal resistance, and the fraction of the whole-cell potential recorded across an intact membrane patch. This analysis revealed a steep increase in the accuracy of recording of steady-state membrane potential as the seal/membrane ratio increases from 0. The recording accuracy approaches 100% as the seal/membrane ratio approaches infinity. Membrane potential measurements across intact cell-attached patches in rat basophilic leukemia cells and rat megakaryocytes revealed a surprisingly high degree of accuracy and demonstrated the ability of this noninvasive technique to follow dynamic changes in potential in nonexcitable cells.
Mason
M J
MJ
Department of Physiology, University of Cambridge, United Kingdom. mjm39@cam.ac.uk
Simpson
A K
AK
Mahaut-Smith
M P
MP
Robinson
H P C
HP
D000244:Adenosine Diphosphate / Q000737:chemistry; D000818:Animals; D002460:Cell Line; D045744:Cell Line, Tumor; D004566:Electrodes; D007938:Leukemia / Q000378:metabolism; D008297:Male; D008533:Megakaryocytes / Q000378:metabolism; D008564:Membrane Potentials; D008962:Models, Theoretical; D018408:Patch-Clamp Techniques / Q000379:methods*; D051381:Rats; D017208:Rats, Wistar; D012965:Sodium Chloride / Q000494:pharmacology
D012965:Sodium Chloride; D000244:Adenosine Diphosphate