Fig. 4.

Increased neuromuscular synaptic activity. (A) Examples of miniature end-plate potential (mEPP) traces obtained from 1-min continuous recording (superimposed traces are shown; 60×, 1-s). mEPP frequencies were significantly increased in E18.5 KO mice compared with WT. (B) Quantification of mEPP frequencies and amplitudes. Frequency: KO (27.99 ± 7.73 events per min, n = 22 cells), WT (1.15 ± 0.13 events per min, n = 13 cells), *P < 0.05; mEPP amplitude (no statistical difference): KO (2.4 ± 0.3 mV, n = 22 cells), WT (2.04 ± 0.3 mV, n = 13 cells). (C) Sample traces of end-plate potentials. (D) Quantification of EPP amplitudes (no statistical difference): WT (14 ± 1.44 mV, n = 9 cells) and KO (16.46 ± 1.01 mV, n = 16 cells). Statistical data are represented as mean ± SEM. (E) Traces of muscle action potentials are comparable in WT and KO. The arrowhead indicates a contraction artifact, which was not observed in KO muscles due to their paralysis.