RESPIRATORY RESPONSE OF SENSITIZED RATS TO CHALLENGE WITH ANTIGEN AEROSOLS

Abstract

The effects of challenging sensitized conscious rats with antigen aerosols were evaluated. The challenge resulted in changes in the respiratory patterns which were antigen-specific and mediated by Ig[immunoglobulin]E antibodies. The response was inducible in non-sensitized rats by passive administration of IgE-rich serum. Sprague-Dawley rats were heterogeneous with respect to the respiratory response. A proportion (20-70%) of each group had continuous dyspnea and other symptoms similar to asthma; the others had only episodes of apnea. Wistar and Long-Evans rats resembled Sprague-Dawley rats; Fischer 344 rats had apnea only, even though they produced IgE antibodies. The type of response did not correlate with serum IgE levels. The respiratory responses were reduced by dexamethasone, disodium cromoglycate, epinephrine and theophylline. Rats that respond with dyspnea may provide a useful experimental model of allergic asthma.