Pharmacologic effects of grain weevil extract on isolated guinea pig tracheal smooth muscle.
Schachter EN; Zuskin E; Arumugam U; Goswami S; Castranova V; Siegel P; Whitmer M; Park J
Am J Respir Crit Care Med 2003 Apr; 167(7):A503
Agricultural farm workers exposed to aerosols of organic compounds are at risk of developing respiratory abnormalities. The Grain Weevil, a parasite infecting grain, is a frequent contaminant of processed wheat. We studied the effect of grain weevil extract (GWE) on isolated guinea pig trachea (GPT) smooth muscle in order to investigate the potential bronchoconstrictor properties of this organic agent. GWE was prepared as a 1:10 w/v solution. The extract was added to GPT in a series of 12 organ baths, in parallel, in 1/2 log dose increments. Dose related contractions of GPT were demonstrated using GWE. Tissue response was measured as a percent of the tissue's maximal contraction to carbachol. The effects of mediator modifying drugs including atropine, indomethacin, pyrilamine (H1 antagonist), acivicin, NDGA, and BPB (which block segments of the arichidonic acid cascade),TMB8 (blocks intracellular calcium mobilization) capsaicin (depletes irritant nerve mediators) and captopril (ACE inhibitor) were tested by pre-treating the tissues with these agents. Endotoxin content of the dust extract was, 2014 EU/mg. Protein analysis revealed 55 mcg/mg of extract. Atropine completely blocked the contractile response of GWE. Pyrilamine, acivicin, BPB, capsaicin, captopril and TMB8 significantly reduced the contractile effects of GWE (p<0.05).As with other organic dusts previously studied, GWE appears to cause a non-immunologically mediated constriction of airway smooth muscle modulated by mediators of inflammation. The cholinergic receptor is prominently involved in this effect. These findings may be related to respiratory abnormalities seen in agricultural workers processing grain.
Pharmacology; Farmers; Agricultural-industry; Agricultural-workers; Agriculture; Organic-compounds; Aerosol-particles; Aerosols; Dust-particles; Dusts; Particulate-dust; Particulates; Respiratory-system-disorders; Endotoxins
Abstract; Conference/Symposia Proceedings
American Journal of Respiratory and Critical Care Medicine, 2003 International Conference, The American Thoracic Society, Seattle, WA, May 16-21, 2003