Fig. 4

CLC-3 Cl⁻ channels and neonatal epileptiform activity. a, b Immunostaining illustrating an upregulation of CLC-3 Cl⁻ channel expression after 0 Mg²⁺ aCSF treatment (1 h). c, d Western blot analysis also confirmed an increase of CLC-3 Cl⁻ channel protein level after 0 Mg²⁺ treatment. Scale bar = 5 μm. e Representative voltage-dependent Cl⁻ current traces in control, 0 Mg²⁺ (1 h), and 0 Mg²⁺ + 20 mM NaGluc (1 h) conditions. f I-V curves showing a significant increase of outward rectifying Cl⁻ currents in 0 Mg²⁺ aCSF group (red) and a remarkable inhibition by NaGluc (green). g, h Representative traces of epileptiform activity induced by 0 Mg²⁺ aCSF in the hippocampal slices from WT (g) and CLC-3 KO mice (h) (P10–12). The blue arrowhead indicates the first ictal burst activity induced by 0 Mg²⁺ aCSF. Note that in the neonatal hippocampal slices from CLC-3 KO mice, the initial epileptiform ictal burst activity later transformed into interictal single spikes (h). i, j Summarized data showing the burst latency (i) and burst number (j) induced by 0 Mg²⁺ aCSF in hippocampal slices from WT and CLC-3 KO mice. k The percentage of slices showing ictal burst activity or interictal spike activity. Data are shown as mean ± s.e.m., unpaired Student’s t-test, *P < 0.05, ** P < 0.01, *** P < 0.001