Mice were intranasally instilled with saline vehicle or ATP (400 nmoles/kg), NPY (4 nmoles/kg), FGF2 (12 pmoles/kg), or a cocktail of ATP and NPY or FGF2. BrdU was injected (i.p., 216 mg/kg total) at 42, 44 and 46 hours and the tissue was collected 48 hours post-instillation. (A–F) Representative images of BrdU immunoreactivity for each group. Dotted white line depicts the apical (AL), neuron (NL) and basal layer (BL). Scale bar = 10 μm. (G) Quantification of BrdU+ cells in the basal layer of OE (n= 9–12 sections from 3–4 mice/group). * indicates significant differences from vehicle at p < 0.05. # indicates a significant difference from NPY at p < 0.05 (two-way ANOVA followed by Newman-Keuls post hoc test).