Figure 4  Muscle Spindles in Gastrocnemius Muscle and TrkA/TrkC Staining in the Tibial Nerve at P0
(A) NF-M (red) and S46 (green) immunostaining in cross section of gastrocnemius muscle at P0. There are no muscle spindles detected in double KOs.
(B) NF-M (red) and S46 (green) immunostaining in parallel sections of gastrocnemius muscle at P0.
(C) NF-M (red) and S46 (green) immunostaining in parallel sections of gastrocnemius muscle at E17. Double null muscles are mostly devoid of muscle spindles, except for one spindle-like structure detected (shown in inset, denoted by the asterisk).
(D) Muscle spindles detected by DiI labeling through the DRG. Gastrocnemius muscle is sectioned at 40 μm thickness in parallel plane to the muscle fibers.
(E) Muscle spindles detected by TrkC staining in cross section of gastrocnemius muscle at P0.
(F) TrkA (red) and TrkC (green) immunostaining in the tibial nerve cross section at P0. TrkC-positive fibers are missing in NT-3 KOs. Red-green overlap (yellow) is due to the thickness of the section and overlapping of red- and green-labeled (TrkA and TrkC) fibers present at different focal depths, rather than co-localization.
Arrows indicate muscle spindles.
Scale bar: 50 μm (A, B, D), 25 μm (C, E), 75 μm (F).