Abstract
NC mice, a model for atopic dermatitis. showed scratching behavior when kept under conventional environment. The scratching behavior of NC mice was suppressed by distraction or by the administration of naltrexone (1 mg/kg, s.c.), an opioid antagonist. These results suggest that such scratching behavior is itchassociated response. The itch-associated response of the NC mice was significantly suppressed by an intravenous injection of nitric oxide (NO) svnthase inhibitor NG-vitro-L-arginine methyl ester (L-NAME, 10 mg/kg), but not D-NAME (10 mg/kg) and saline. Intracutaneous NO production in the rostral back. a region which the NC mice mainly scratched. was markedly increased as compared with the caudal back. a nonscratched region. The increased NO production in the rostral back of NC mice was decreased by the intravenous injection of L-NAME (10 mg/kg). These results suggest that NO and NO sythase are new target in the treatment of atopic pruritus.
