The dynamic Na⁺ pump and Kv7 channels account for short-term feedback, with variable contributions from cell to cell.

(A) Example recordings showing the effect of 2 μM ouabain (dynamic Na+ pump, n = 12 cells from N = 8 animals), 10 μM XE-991 (Kv7, n = 17 cells from N = 5 animals), and 30 μM Cd2+ (Ca2+ channels, n = 14 neurons from N = 4 animals) on the usAHP. (B) 2 μM ouabain and 10 μM XE-991 reduced the usAHP in most neurons, while 30 μM Cd2+ did not. The frequency of positive effects differed across drugs (Chi-square test; p = 0.012). (C) Mean changes in the usAHP by each drug (one-way ANOVA followed by Holm–Sidak Multiple Comparison test). (D) Correlation between sensitivity of the usAHP to ouabain and the drop in the first Rin measurement following stimulation. Traces illustrate Rin responses for each example neuron at different ends of the correlation. (E) Same as (D) but for XE-991. (F) Correlation between sensitivity of the usAHP and the drop in Rin after block of Kv7 by XE-991. The x-axis shows the ratio of the change in Rin during the usAHP after and before XE-991. Thus, greater values reflect a greater block of the Rin drop following XE-991. Inset for (E) shows the ability for XE-911 to counter the drop in Rin in neurons where XE-991 also reduced the usAHP. The data underlying this figure can be found in S1 Data.