Pharmacological Studies of the Effect of Wheat Grain Extract

Background: Agricultural farm workers exposed to wheat grain dust are at risk of developing respiratory abnormalities. The pathogenesis of this injury is only partially understood. Objectives: To determine the effect of wheat grainextract on isolated guinea pig tracheal smooth muscle. Methods: In the current study, pharmacologic properties of wheat grain extract (WGE) were tested using guinea pig tracheas studied in vitro. Dose-related contractions of nonsensitized guinea pig trachea were demonstrated using these extracts. Pharmacologic studies were performed by pretreating guinea pig tracheal tissue with drugs known to modulate smooth muscle contraction: atropine 10 –6 M, indomethacin 10 –6 M, pyrilamine 10 –6 M, acivicin 10 –5 M, nordihydroguaretic acid (NDGA) 10 –5 M, bromophenacyl bromide (BPB) 10 –5 M, 3,4,5-trimethoxybenzoic acid-8-(diethylamino)- octyl ester TMB8 10 –5 M, captopril 10 –5 M and capsaicin 5 × 10 –6 M. Results: WGE causes a dose-dependent constriction of guinea pig tracheal smooth muscle. Atropine, pyrilamine, TMB8 and acivicin significantly reduced the contractile effects of the WGE. Inhibition of contraction by blocking of other mediators was significant but less complete. Conclusion: We conclude that WGE causes a dose-related constriction of airway smooth muscle by nonimmunological mechanisms involving a variety of airway mediators and possibly cholinergic receptors.