Effect of Protease-Activated Receptor-2-Activating Peptide on Guinea Pig Airway Resistance and Isolated Tracheal Strips.

Purpose: Protease-activated receptors (PARs) are a family of G-protein-coupled receptors distributed in a number of tissues. PAR-2 is expressed on airway epithelium and smooth muscles and overexpressed under pathological conditions, such as asthma and chronic obstructive pulmonary disease. However, the role of PAR-2 in airways has not yet been defined. In this study, we investigated the role of PAR-2-activating peptide (SLIGRL) on histamine-induced bronchoconstriction and the mechanisms underlying the bronchoprotective effect both and .

Materials And Methods: The effect of SLIGRL was tested using histamine-induced bronchoconstriction in the guinea pig and using isolated tracheal spiral strips.

Results: pretreatment with SLIGRL significantly reduced the histamine-induced increased bronchoconstriction. Neither propranolol nor vagotomy abolished the inhibitory effect of SLIGRL. Furthermore, indomethacin or glibenclamide did not antagonize the inhibitory response to SLIGRL. In isolated tracheal spiral strips , SLIGRL did not affect the contractile response to acetylcholine or potassium chloride; however, histamine-induced contraction was inhibited in a dose-dependent manner.

Conclusion: Our data demonstrate the protective effect of SLIGRL in airways; however, this effect appears to be mediated independently of prostanoids, nitric oxide, circulating adrenaline, ATP-sensitive K + channels, and vagal stimulation.