Figure 2: Ensemble potassium channel activity in cell-attached patches generates whole-cell currents.
From: Errors in the measurement of voltage-activated ion channels in cell-attached patch-clamp recordings
(a) Simultaneous whole-cell recording of ensemble potassium channel activity generated in a cell-attached patch (IC-A) under whole-cell voltage-clamp (v-c) or current-clamp (c-c) conditions from the soma of a stratum radiatum interneuron of the CA1 region of the hippocampus. Note that under whole-cell v-c, an outward current with kinetics and amplitude similar to the cell-attached current was recorded (IW-C). When the whole-cell voltage was not clamped, under c-c recording conditions, the amplitude and shape of the cell-attached current was modified and a prominent hyperpolarizing voltage response recorded intracellularly (Vm). The pipette voltage command ramp is shown (VP). (b) The peak amplitude of outward currents gated by ensemble potassium channel activity is similar when recorded at the cell-attached (C-A) and whole-cell (W-C) level in stratum radiatum interneurons (n=11) and thalamocortical (TC) neurons (n=18). (c) The charge of ensemble potassium channel activity in cell-attached patches is significantly different when the simultaneous whole-cell recording is configured in v-c or c-c mode. (d) Relationship between the amplitude of potassium currents in cell-attached patches and hyperpolarizing voltage changes in stratum radiatum interneurons. Data have been fit by a single exponential function (line). Pooled data are shown as mean±s.e.m., statistical significance was determined with a paired Student's t-test.
