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. 2021 Jan 13;41(2):376–389. doi: 10.1523/JNEUROSCI.2142-20.2020

Figure 5.

Figure 5.

4-AP improves synaptic function of sensory-motor circuit in SMA mice. A, CMAP recordings from the QL muscle following L1 ventral root stimulation from WT, SMA, and SMA + 4-AP mice at P11. Arrows indicate maximum amplitude. Scale bars: 0.5 mV, 3 ms. B, Quantification of CMAP amplitudes recorded from the QL muscle in the same groups as in A. CMAP in millivolts: WT (6) = 1.52 ± 0.16, SMA (6) = 0.05 ± 0.01, SMA + 4-AP (6) = 0.45 ± 0.02, p for WT versus SMA < 0.0001, p for WT versus SMA + 4-AP <0.0001, p for SMA versus SMA + 4-AP = 0.0228, one-way ANOVA with Tukey's correction. Number of mice is reported in parentheses. C, Representative traces of extracellular recordings from L1 ventral root (VR) following L1 dorsal root (DR) stimulation from the same groups as in A. Shaded area marks the monosynaptic response. Arrowheads indicate the stimulus artifact. Scale bars: 0.2 mV, 5 ms. D, Quantification of spinal ventral root amplitudes recorded from the same groups as in A at P11. Amplitude in millivolts: WT (5) = 1.15 ± 0.05, SMA (6) = 0.15 ± 0.04, SMA + 4-AP (7) = 0.45 ± 0.10, p for WT versus SMA < 0.0001, p for WT versus SMA + 4-AP <0.0001, p for SMA versus SMA + 4-AP = 0.0458, one-way ANOVA with Tukey's correction. Number of mice is reported in parentheses. E, Representative traces of the first (black) and fifth (red) VR responses recorded at P11 following stimulation of the homonymous L1 DR at 10 Hz from the same groups as in A. Scale bars: 0.2 mV and 10 ms. Inset scale bars: 0.1 mV, 5 ms. F, Quantification of amplitude changes in percent of the monosynaptic ventral root response following 10-Hz stimulation from the same groups as in A. Number of mice for WT = 7, SMA = 6, SMA + 4-AP = 6, p for SMA versus SMA + 4-AP at stimulus 5 = 0.0204, multiple t test with Holm–Sidak method. G, Single optical plane confocal images of L1 ChAT+ motor neurons (blue) expressing Kv2.1 channels (yellow) from the same groups as in A at P11. H, Percentage of somatic coverage of Kv2.1 expression in motor neurons for the same experimental groups shown in A. WT (16) = 76.83 ± 3.38, SMA (23) = 52.4 ± 3.49, SMA + 4-AP (21) = 66.77 ± 3.64, p for WT versus SMA < 0.0001, p for SMA versus SMA + 4-AP = 0.0113, one-way ANOVA with Tukey's correction. Number of motor neurons from three mice is reported in parentheses. Data are presented as mean ± SEM. Asterisks on top of bars without a horizontal line indicate the significance compared with the WT group; *p < 0.05, **p < 0.01, ***p < 0.001.