Antigen-induced elevation of immunoreactive endothelin-1 (ET-1) levels in ovalbumin-sensitized guinea pig airway tissue

Changes in the immunoreactive ET-I levels during the anaphylactic reaction of airway tissue from ovalbumin-sensitized guinea pigs were investigated. E T-l-immunoreactivity (ET-IR) was detected in the epithelial and smooth musc le layers of tracheal sections from normal guinea pigs and it was enhanced slightly by phosphoramidon (I mu M) treatment. The ET-IR level of the epith elial layer of ovalbumin-treated tissue from actively sensitized animals wa s slightly higher than that from normal animals, but it was enhanced marked ly by phosphoramidon (1 mu M) treatment. Furthermore, the mean ET-IR level of homogenates of antigen-treated tracheal tissues from sensitized guinea p igs (22.8 +/- 1.55 fmol mg(-1) protein, n = 5) was significantly higher tha n the corresponding normal level (12.3 +/- 1.21 fmol mg(-1) protein, n = 5) . These results suggest that increased epithelial airway ET-1 levels contri bute to the anaphylactic reaction of guinea pig airways. (C) 1999 Elsevier Science Inc. All rights reserved.