Pharmacologic Effects of Cocoa and Rye Flour Extracts on Isolated Guinea Pig Trachea

Abstract

Confectionery workers are exposed to a wide variety of organic dusts and aerosols. Previous studies with workers in a confectionery plant working with cocoa and rye flour indicate that these workers are at risk of developing adverse respiratory symptoms and lung function impairment. The effects of cocoa and rye flour extract on isolated guinea pig tracheal smooth muscle were studied using water-soluble extracts from cocoa and rye flour obtained from the studied confectionery plant. Dose-related contractions of nonsensitized guinea pig tracheal rings were demonstrated using both cocoa and rye flour extracts. Pharmacologic studies were performed by pretreating guinea pig tracheal tissue with drugs known to modulate smooth muscle contraction: atropine, indomethacin, pyrilamine, nordihydroguaiaretic acid (NDGA), acivicin, bromophenacyl bromide (BPB), 3,4,5-trimethoxybenzoate 8-(N,N-diethylamino)octyl ester (TMB8), captopril, and capsaicin. Constrictor effects of the dust extracts were inhibited by these agents, the pattern of which depended on the dust extract. Atropine consistently and significantly reduced the contractile effects of both extracts. These observations suggest a release of parasympathetic mediators by these extracts or more directly an interaction with muscarinic receptors. In addition, the constrictor effect of cocoa and rye flour extracts was significantly, but only partially, reduced by indomethacin, pyrilamine, BPB, and TMB8. Acivicin also partially decreased the constrictor effect of cocoa extract. Pretreatment of tracheal tissue with capsaicin also decreased the constrictor effects of high concentrations of cocoa and rye flour extracts. Data suggest that cocoa and rye flour extracts cause a dose-related constriction of airway smooth muscle by non immunological mechanisms involving cholinergic pathways and airway mediators such as histamine and the products of the arachadonic acid cascade. This effect is not dependent on the presensitization of guinea pigs.