Figure 4

Female mice demonstrate CMAP functional differences absent of abnormal NMJ morphology. (A) Schematic of CMAP stimulating and recording electrode placement along the sciatic nerve within the hindlimb of test mice. (B) Distal amplitude recordings in male (left) and female (right) control-GFP and GR50-GFP mice at 3- and 6- months old. Males: n = 5 GR50-GFP, 7 control-GFP; time x genotype p = 0.2385. Females: n = 5 mice per genotype; time x genotype p = 0.0386. Two-way ANOVA, Sidak’s multiple comparisons test. (C) Nerve conduction velocity in male (left) and female (right) control-GFP and GR50-GFP mice at 3- and 6- months old. Males: n = 5 GR50-GFP, 7 control-GFP; time x genotype p = 0.8522. Females: n = 5 GR50-GFP, 4 control-GFP; time x genotype p = 0.7671. Two-way ANOVA, Sidak’s multiple comparisons test. (D) Representative distal CMAP stimulus trace of a female control-GFP and GR50-GFP mouse at 3 months and (E) 6 months. Dashed line indicates 0 mV. (F) Representative images of the neuromuscular junctions of the extensor digitorum longus muscle of female control-GFP and GR50-GFP mice at 3-months-old stained for presynaptic SV2 and postsynaptic alpha-bungarotoxin. Scale bar = 50 µm. (G) Quantification of the innervation status of NMJs of the soleus and extensor digitorum longus muscles of female control-GFP and GR50-GFP mice at 3-months-old. n = 3 mice per time-point, mean ± s.e.m. Two-way ANOVA, Sidak’s multiple comparisons test. Fully Innervated: p = 0.0717, Partially Innervated: p = 0.3016, Fully Denervated: p = 0.7910.