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The Interpretation of Current-Clamp Recordings in the Cell-Attached Patch-Clamp Configuration

2004; Elsevier BV; Volume: 88; Issue: 1 Linguagem: Inglês

10.1529/biophysj.104.049866

1542-0086

Mike J. Mason, Anna K. Simpson, Martyn P. Mahaut‐Smith, Hugh P. C. Robinson,

Ion channel regulation and function

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.