Galanin expression in a murine model of allergic contact dermatitis

Galanin is a neuropeptide widely distributed in the nervous system. The expression of galanin was investigated in murine contact allergy using immunohistochemistry, radioimmunoassay and in situ hybridization. Female BALB/c mice were sensitized with oxazolone and 6 days later challenged on the dorsal surface of ears, while control mice received vehicle. After 24 h, one ear was processed for immunostaining using a biotinylated fluorescence technique, while the other ear was frozen and processed for radioimmunoassay or in situ hybridization. Galanin immunoreactive nerve fibres were more numerous (p < 0.01) in the eczematous compared with control ears. Double-staining with antibody to the nerve fibre marker PGP (protein gene product) 9.5 revealed colocalization of PGP 9.5 and galanin in nerve fibres. Radioimmunoassay demonstrated a decrease (p < 0.04) in galanin concentration in eczematous compared with control ears. Our results suggest a role for galanin in murine contact allergy.