Evaluation of pulmonary mechanics in guinea pigs during respiratory anaphylaxis

Guinea pigs sensitized to ovalbumin exhibit signs of respiratory impairment when exposed to an aerosol of the antigen. This response was investigated in anesthetized guinea pigs by determining forced pulmonary mechanics to derive peak expiratory flow rate, forced vital capacity, forced expiratory volume in 0.1 sec, maximal mid-expiratory flow rate and respiratory rate. Measurement of these parameters allows qualitative comparisons to be made with changes that are routinely determined during investigations of human asthma. Exposure of anesthetized guinea pigs to a 3% ovalbumin aerosol for 2 min produced an increase in respiratory rate, a 20% fall in peak expiratory flow rate and maximal mid-expiratory flow rate, a 50% fall in forced vital capacity and a 40% fall in forced expiratory volume in 0.1 sec. This response was reversed by aminophylline. In these respects the response appears to be similar to the acute asthmatic response in humans.