Chlorhexidine inhibits L1 mediated neurite outgrowth. Cerebellar granule neurons are plated on either poly L-lysine (PLL) alone or PLL plus L1-Fc (L1), then ethanol (E, final concentration 25 mM), chlorhexidine vehicle (V, final concentration 1%)) or chlorhexidine in vehicle (CHG, final concentration 1.0 μg/ml CHG, 1% vehicle) are added to the media. The cells are grown for 24 h, fixed and immunostained. Representative photomicrographs are shown: A) PLL alone; B) L1; C) L1 + V; D) L1+V+CHG. Magnification 20X.