Figure 2.

Patch-clamp recording of transmembrane currents in A. polypoides cells. (A) Voltage ramps of 5-s duration were applied from a holding potential of −20 mV in whole-cell configuration. Currents were recorded at 14°C and 26°C, as indicated. Sampling and filtering frequencies were 2 and 0.5 KHz, respectively. Cells were bathed with external artificial SW and internal IntA solution. The arrows show the monovalent cationic [V_rev(C⁺) caused by Na⁺ and K⁺] and anionic [V_rev(A⁻) caused by Cl⁻] reversal potentials, as calculated for the bathing and internal solutions in use. (Inset) The inhibition of the high temperature-induced current by 100 μM Gd³⁺. (B) Currents recorded before, during, and after application of AA (100 μM), at T = 14°C under the same experimental conditions as in A. (Inset) The inhibition of the AA-induced current by 300 μM La³⁺. (C) Single-channel recording of mechanical stress-activated channels in cell-attached configuration. Channel activity was recorded at atmospheric pressure and during stretch of −84 mmHg applied through the recording pipette (V_m = 20 mV), at 4-KHz sampling and 1-KHz filtering frequencies. Cells were bathed with external artificial SW and IntB solution into the pipette. (Inset) The single-channel I–V relationship and some example traces, measured at the minimum stretch needed to elicit the current. Each point has been evaluated from at least 50 single-channel transitions, and bars show the SEM. The channel conductance calculated from the best fit was 13 ± 4 pS.