Effects of exposure to sulfate aerosols and antigen on breathing curve patterns of guinea pigs.

We investigated the effects of ammonium sulfate aerosols on asthmatic dyspnea (immediate type) induced by repeated inhalation of a mixture of bovine serum and egg albumin and on the nonspecific responsiveness of the airway tract to acetylcholine. Guinea pigs were exposed to sulfate aerosol in concentrations of 0.2, 0.4, and 2.0 mg/m3 and to 0.2 mg/m3 sulfate aerosol combined with 0.1 ppm of SO2. The exposure time was 2 h/d, 5 d/wk, 38 times in all. The animals were successively exposed to aerosol (for 2 h) and, after 30 min, to the spraying of albumin solution 3 times per week, 7 or 9 times in all. Breathing curves were continuously recorded by a body plethysmograph system during the sensitization periods. The experiments showed that the degree of asthmatic dyspnea in guinea pigs was increased by the exposure to aerosol, and that there is a quantitative relation between the severity of the dyspnea and extent of the exposure. Exposure in the combination with SO2 showed no effect at the concentration studied. Following the exposure experiment, each group of animals was exposed to the spraying of acetylcholine. The sensitivity to acetylcholine increased at aerosol concentrations of 0.4 and 2.0 mg/m3.