Figure 1.

Effect of pipette potential and pipette solution on firing rate as measured in cell-attached recording. A, Representative traces obtained in cell-attached mode when using a K⁺-filled pipette at two different pipette potentials, yielding different firing rates (−40 mV, 1.5 Hz; −60 mV, 0.9 Hz). Pipette input resistance 11.2 GΩ. B, Semi-log graph of summary data showing the dependence of firing rate on pipette potential with K⁺-filled pipettes (6 experiments with K-gluconate and 7 experiments with KCl). There is a significant increase of firing rate on potential (p < 0.01), with a slope corresponding to a twofold factor in 27 mV. Each experiment comprised a recording taken at −60 mV, and the firing rates were normalized to the value observed at this potential (black dot). C, Likewise, the firing rate increases significantly with potential when using NaCl-filled pipettes (n = 8 cells; p < 0.01), but the slope is more shallow (2-fold factor in 62.7 mV).