1% BSA. Immunoreactive signals were detected using the enhanced chemiluminescence system (Millipore, Bedford, MA). To quantify the relative amount of ChAT protein, the blots were stripped and reprobed with an antibody against glyceraldehyde-3-phosphate dehydrogenase (GAPDH) [1:2000] (Biodesign, Saco, ME) for 1 h, followed by a horseradish peroxidase Inhibitors,research,lifescience,medical conjugated antibody [1:2000]. The ChAT and GAPDH

bands were quantified using the Genetools Analysis Software (Syngene, Cambridge, UK). ChAT immunoreactivity was normalized to GAPDH and the relative amount of ChAT protein in L1-deficient mice was expressed as a percent of ChAT present in wild-type littermates. ChAT activity ChAT activity was measured as previously described (Burgess and Aubert 2006; Burgess

et al. 2009), using the method of Fonnum (1969), modified by Tucek (1978). Briefly, each sample dissected from septal and striatal regions was homogenized, diluted, and TSA HDAC incubated with [14C] acetyl CoA at 37°C for 30 min. Homogenates prepared from septal Inhibitors,research,lifescience,medical cells in vitro were incubated for 50 min. The reaction was then stopped, and the newly formed [14C]acetylcholine was extracted, counted, and expressed as nanomoles of acetylcholine produced per milligram of protein per hour (nmol ACh/mg prot/h). The final Inhibitors,research,lifescience,medical value for each sample represents an average of duplicates. Immunostaining Coronal brain sections were cut at 50 μm on a freezing microtome, collected serially Inhibitors,research,lifescience,medical in 96-well plates filled with cryoprotectant, and stored at −20°C. Sections from L1-deficient mice and their wild-type littermates were processed simultaneously using standard immunostaining procedures for fluorescence microscopy (Aubert et al. 1998) and stereology (Ypsilanti et al. 2008). For immunofluorescence staining, sections were rinsed in 0.1 M Tris-buffered saline

(TBS, pH 7.4) and incubated in TBS with 5% normal donkey serum and 0.25% Triton X-100 for 1 h at room Inhibitors,research,lifescience,medical temperature. For the combined detection of ChAT and L1, the goat anti-ChAT antibody [1:100] (AB144P, Chemicon) and the rabbit anti-L1 antibody [1:1000] (a generous gift from Dr. Stallcup et al. 1985) were used overnight at 4°C. Sections were rinsed and incubated with donkey anti-goat and donkey anti-rabbit secondary antibodies [1:200] (Jackson ImmunoResearch) coupled to biotin Non-specific serine/threonine protein kinase and indocarbocyanine (Cy3), respectively, for 2 h at room temperature in the dark. Sections were rinsed and incubated for 2 h in the dark with streptavidin-Alexa 488 and the nucleic acid staining cyanine dye monomer TO-PRO-3 iodide (2 μM). Sections were rinsed and mounted on presubbed slides, allowed to dry briefly, and coverslipped with a 10% solution of polyvinyl alcohol containing 2.5% 1,4-diazabicyclo-2,2,2-octane (PVA/DABCO, both from Sigma, St. Louis, MO).