Histamine release by Western red cedar (Thuja plicata) from lung tissue in vitro.

Abstract

<b>Evans, Elizabeth and Nicholls, P. J. (1974).</b><i>British Journal of Industrial Medicine,</i><b>31,</b> 28-30. <b>Histamine release by Western red cedar</b><i>(Thuja plicata)</i><b>from lung tissue in vitro.</b> Various respiratory symptoms have previously been observed in workers exposed to dust from Western red cedar (<i>Thuja plicata</i>). Although an allergic basis for these effects has been proposed, the possibility that the dust may contain a pharmacologically active agent was investigated. Aqueous extracts of two samples of red cedar released significant amounts of histamine from pig and human lung <i>in vitro</i>. For one of these samples, using pig lung, a dose-response relation was found over a narrow range of concentrations. These dusts possessed the same order of histamine-releasing activity as a sample of cotton dust. Potassium cyanide reduced the release of histamine caused by low concentrations of Western red cedar. Similar effects of cyanide on the histamine-releasing activity of cotton dust and compound 48/80 were observed. It is possible that release of histamine in the lungs and upper respiratory tract occurs on inhalation of dust from Western red cedar and this may be a contributory factor to the development of respiratory symptoms in workers exposed to the dust of this wood.