Figure 5.

KCC2 protein is not lost as dramatically on γ motoneurons (γMNs) as αMNs. A, B, Confocal images of the ventral horn containing sciatic injured MNs labeled with antibodies against ChAT (green) and ATF3 (red) to mark axotomized MNs, and KCC2 (white) 14 d after sciatic nerve cut/ligation. Uninjured MNs in the side contralateral to the injury (top) lack ATF3 and have similar levels of KCC2-IR in α (large) and γ (<475 μm², yellow arrowheads) MNs. After injury (B) KCC2-IR consistently disappears from αMNs, but is more variably depleted in γMNs (yellow arrowheads). C, High magnification of αMNs and γMNs marked in B. γMNs has some KCC2 preserved on the somatic membrane. Scale bars = 20 μm. D, Quantification of KCC2-IR on the membrane of individual MNs (single points) ipsilateral and contralateral to injury. αMNs consistently deplete KCC2 from the somatic membrane after injury, and while there are no statistically different differences in KCC2-IR of intact MNs ipsilateral and contralateral to injury, the difference between injured and uninjured γMNs is not significantly different (Table 4). γMNs do not exhibit KCC2 loss as consistently as αMNs at this time point. ***p < 0.001; *p < 0.05; n.s. = not significant.