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. 2021 Jan 29;599(6):1855–1883. doi: 10.1113/JP281044

Figure 8. Changes in holding and steady‐state currents in response to bath‐applied low Na+ saline.

Figure 8

A, holding current recording. CCs were voltage‐clamped at −50 mV (a value near RMP). Substitution of NaCl by NMDG (Aa) or Tris (Ab) decreases the holding current, with the appearance of an outward current (mean amplitude: −2.9 ± 6.6 pA versus 16.1 ± 14.1 pA, in control and NMDG‐containing saline, respectively, n = 9 cells, P < 0.01 ( = 0.0078), Wilcoxon matched‐pairs signed‐rank test and −2.8 ± 6.1 pA versus 4.8 ± 10.8 pA, in control and Tris‐containing saline, respectively, n = 12 cells, P < 0.05 ( = 0.0161), Wilcoxon matched‐pairs signed‐rank test). B, steady‐state membrane currents evoked by voltage steps (150 ms duration) made from an initial holding potential of −30 mV in 10 mV decrements. Note the substantial decrease of the current amplitude in response to bath‐applied low Na+ (NMDG replacement, Ba). Bb, I‐V relationship of the subtracted currents (n = 26), combined with the confidence band at 95%. Current amplitudes were calculated from the average of a 10 ms window at the end of each 150 ms step. The ‘low Na+‐sensitive current’ exhibits a linear I‐V relationship, indicative of its voltage independency. The current reverses at −12.4 mV, arguing for a mixed ionic current. [Color figure can be viewed at wileyonlinelibrary.com]