Figure 1

Poor voltage clamp quality in astrocyte recording. (a) DIC and SR101 fluorescent images of a dual patch recorded astrocyte in the hippocampal CA1 stratum radiatum region; electrode 1 (E1) and electrode 2 (E2) were in voltage clamp and current clamp modes, respectively. (b) Whole-cell current profiles of an astrocyte and an NG2 glia are shown as indicated; the cells were held at resting (-80 mV), then stepped to command voltages from -180 mV to +20 mV with 20 mV increments (inset). (c, d) Comparison of command voltages (V_C) applied through E1 and the resultant potentials across the membrane (V_M) measured from E2 for the recorded astrocyte and NG2 glia, respectively. (e, f) The I-V_C and I-V_M were plotted in the same chart for voltage clamp quality comparison. (g) The R_t was plotted against V_M/ΔV_C (n = 44) and fitted with ΔV_M/ΔV_C = aR_t^b; the V_M/ΔV_C decreases with increasing R_t, which yields R_M and exponent values of 5.73 MΩ and -0.995, respectively. (h) Comparison of I-V_M relationships in the presence and absence of R_a compensation, showing a good voltage clamp quality after R_a compensation.