Fig. 5

Role of K⁺ uptake and Na⁺/K⁺-ATPase activity in glutamate clearance in the ACC. a Transients of iGluSnFR signals at baseline (black traces) evoked by single stimulation, trains of 50 Hz and 100 Hz stimuli and in the presence of 200 µM BaCl₂ (red traces). b Blockade of KIR-dependent K⁺ uptake by BaCl₂ did not affect glutamate decay kinetics following a single stimulation (baseline: 35.6 ± 2.7 ms; BaCl₂: 34.3 ± 2.3 ms; n = 5, P > 0.05). However, BaCl₂ significantly slowed the decay of iGluSnFR signals in the ACC at 50 Hz by 13% (baseline: 105.9 ± 7.7 ms; BaCl₂: 119 ± 9.1 ms; n = 5 slices, ** P < 0.01). The presence of BaCl₂ had smaller effects on the decay kinetics at 100 Hz (baseline: 83.1 ± 0.1 ms; BaCl₂: 91.0 ± 8.9 ms, n = 5, P > 0.05). c In the presence of BaCl₂ in the ACC, the decay of glutamate transients remain significantly faster at 100 Hz (91 ± 8.9 ms) compared with 50 Hz (119 ± 9.1 ms; n = 5 slices, N = 1, **P = 0.006). Traces normalized to the peak. d Same as (a), but in the presence of 5 µM ouabain (orange traces). e Blockade of Na⁺/K⁺-ATPase by ouabain slowed down glutamate transients drastically at all stimulation intensities with a larger effect at 100 Hz (single pulse, baseline: 30.6 ± 3.2 ms; ouabain: 61.42 ± 8.7 ms; n = 10 slices, * P < 0.05. At 50 Hz, baseline: 99.3 ± 6.6 ms; ouabain: 173.4 ± 9.7 ms; n = 10 slices, ***P < 0.0001. At 100 Hz: baseline: 82.7 ± 5.7 ms; ouabain: 179.1 ± 18.6 ms, n = 10, ***P < 0.0001, n = number of slices, N = number of mice). f In the presence of ouabain in the ACC, the decay of glutamate transients becomes comparable, with non-significant difference between 50 and 100 Hz. Traces normalized to the peak. Data are mean ± SEM. Two-way RM ANOVA test and two-tailed paired t test