Mice were deeply anesthetized with 100 mg/kg sodium pentobarbital and perfused transcardially with 10 mL of 0.1 M PBS followed by 30 mL of 3.7% formaldehyde solution (Sigma-Aldrich). The lumbar dorsal root ganglia (DRG) and spinal cord were dissected, post-fixed in the same fixative for 4 hrs, and cryoprotected overnight in 30% sucrose in 0.1 M PBS. Spinal cords were sectioned on a cryostat at 40 μm and processed as free-floating sections. DRG were sectioned at 20 μm and processed on slides (Superfrost, Fisher Scientific). Tissue was first incubated for at least 1 hr in 0.1 M PBS with 0.3% Triton X-100 (Sigma-Aldrich) plus 5% normal donkey serum (NDS, EMD-Millipore) blocking solution. Primary antibodies were diluted in 0.1 M PBS with 0.3% Triton X-100 plus 5% NDS. Secondary antibodies were diluted in 0.1 M PBS with 0.3% Triton X-100 plus 1% NDS. Tissue was incubated overnight at 4°C in primary antibody, washed with 0.1 M PBS with 0.3% Triton X-100 plus 1% NDS, and then incubated for 2 hrs in secondary antibody at RT. Tissue was then washed with 0.1
