(A) Representative traces of isoguvacine (Iso) responses illustrating the reversal of the evoked GABAAR-related current (EGABAAR) in WT and SOD MNs. Holding voltage −70 mV, −60 mV, −50 mV and −40 mV. I/V relationships, plotted below the traces, revealed that EGABAAR was −61.4 mV and −48.5 mV in the representative WT and SOD MNs, respectively. (B1) Mean EGABAAR was significantly lower in E17.5 WT (n = 25) compared to SOD (n = 24) MNs from the same litter. (B2) Accordingly, the mean [Cl-]i, calculated from individual EGABAAR values, indicated that SOD MNs had a higher [Cl-]i than WT. (B3) Mean resting membrane potential (Em) did not differ in WT and SOD MNs. (B4) Mean driving force (DF) for chloride ions was doubled in SOD MNs compared to WT MNs. Values illustrated were from the same set of MNs. ****p<0.0001, ***p<0.001, ns non-significant, Mann Whitney test.