Figure 2.

Central patterns of labeling for VGLUT1, CTb, and NPY in the gracile nuclei 2 weeks after unilateral SNT and subsequent CTb injection into the lesioned nerve. a, b, VGLUT1 is shown in the ipsilateral (a) and contralateral (b) gracile nucleus. c, d, and e show CTb, NPY, and merged CTb/NPY labeling in the ipsilateral nucleus, and f–i show a high-magnification view from the ipsilateral nucleus to reveal CTb (f), NPY (g), VGLUT1 (h), and all three types of immunostaining (i). The outer dashed lines in a and c–e, and the dashed line in b represent the outline of the gracile nucleus. The inner dashed line in a and c–e indicates the region in which the majority of NPY-immunoreactive axons were located (as shown in d). On the ipsilateral side, there is a reduction in VGLUT1 labeling in the area outlined by the inner dashed line (a) compared with that seen on the contralateral side (b), and CTb-labeled primary afferent terminals are present in the same area (c). CTb labeling and NPY expression are found in directly overlapping areas in the ipsilateral gracile nucleus (e). High-magnification views show colocalization of CTb (f) and NPY (g) in lesioned primary afferent terminals (some indicated by arrows), but these have no detectable VGLUT1 (h). Scale bars: a–e, 100 μm; f–i, 10 μm.