FIGURE 5.

Representative single-channel Ba²⁺ currents. (A) Voltage protocol used to elicit single-channel currents in B and C. Patches were held at −100 mV, depolarized to 0 mV for 3 ms, and then hyperpolarized to the test potential. Recordings were made during the final 15 ms of the 3-s interpulse interval, during the 3-ms depolarization to 0 mV, and for 80 ms at the test potential. (B) Capacity- and leak-corrected single-channel currents elicited with the tail protocol shown in A from a holding potential of −100 mV in 5 mM Ba²⁺ (upper) and 60 mM Ba²⁺ (lower). Top currents were sampled at 4 kHz and filtered at 2 kHz. Bottom currents were sampled at 20 kHz and filtered at 2 kHz and then downsampled to 4 kHz offline. The seal resistance was >100 GΩ in each patch.