Immunohistochemical localization of transient receptor potential vanilloid subtype 1 in the trachea of ovalbumin-sensitized guinea pigs

Background: We previously found many transient receptor potential vanilloid receptor subtype 1 (TRPV1) axons in the tracheal smooth muscle and epithelium of the guinea pig airway. One report indicates that the number of TRPV1 axons is significantly increased in patients with cough variant asthma. Aim: To determine whether the distribution of TRPV1 in the airways is altered in guinea pigs with an allergic phenotype. Methods: Ten guinea pigs were assigned to 2 groups in a double-blind study. Five animals were sensitized with ovalbumin and the other 5 underwent sham sensitization. Cryopreserved sections (30 mu m) of tracheal tissues removed from each animal were stained with polyclonal serum rabbit anti-TRPV1 antibody (1: 30,000) and examined by confocal microscopy. Results: Axons immunoreactive to TRPV1 localized to fine axons within the epithelium and around areas of smooth muscle, were more densely stained and frequent in the ovalbumin than in the sham group. Conclusion: The number of TRPV1-immunoreactive axons in the trachea increases under allergic inflammatory conditions. Copyright (C) 2008 S. Karger AG, Basel.