Fine particles of cotton dust influence histamine release

Cotton dust particle distribution in respiratory airways was measured to determine if specific size particles of the heterogeneous dust are concentrated as a function of airway diameter. Previously reported work indicated that the fine particles are responsible for the decrement in pulmonary function which occurs subsequent to cotton dust inhalation. After recovery, particles were sized and counted microscopically. Significant increases in fine particles (5-7 mu) were found in all airways of exposed animals as compared with controls. These particles become more concentrated as the airway diameter decreased. Histamine determinations were made in mice lungs after the animals were exposed to cotton dust for various periods of time to see if such treatment could be correlated with elevations in the concentrations of this biogenic amine. Lung histamine increased as exposure time to cotton dust increased. It is concluded that the lung histamine release occurring after cotton dust inhalation is related to some property of the fine particles of the heterogeneous dust.