BUDESONIDE INHIBITS PLASMA EXTRAVASATION INDUCED BY CAPSAICIN AND BY SUBSTANCE-P IN THE RAT NASAL-MUCOSA

We studied the effect of the locally administered glucocorticoid budes onide on plasma extravasation induced by capsaicin and by substance P (SP) in the nasal mucosa of pathogen-free rats. Using Evans blue dye a s a tracer, we measured plasma extravasation induced by capsaicin (150 mu g kg(-1) i.v.) or SP (0.5 and 2.5 mu g kg(-1) i.v.) in the rat nas o- and maxilloturbinates after pretreatment with budesonide (0.1-50 mu g twice/day for 2 days in the right nostril; 50 mu g only for SP) or its vehicle. We found that budesonide inhibits plasma extravasation in duced by capsaicin in a dose-dependent fashion in the nasal cavity. Af ter the highest dose (50 mu g) of budesonide, the values of Evans blue in the nasal mucosa were not different from the values observed after capsaicin vehicle alone. Budesonide also reduced plasma extravasation induced by capsaicin in the trachea and the urinary bladder of the ra ts in a dose-dependent fashion. Budesonide (50 mu g) delivered to the nose inhibited the plasma extravasation caused by 0.5 but not by 2.5 m u g SP kg(-l) in the nasal mucosa. We conclude that the postjunctional part of the neurogenic pathway is a target for glucocorticoid antiinf lammatory action in the nasal mucosa, at least of the rat. Budesonide' s effect on organs other than the nose can be explained by systemic ab sorption.