The effects of antigen inhalation challenge with Ascaris suum extract and of tracheobronchial irritation with ozone (03) on pulmonary (R(L)), dynamic compliance (C(D)) and tracheal mucous velocity (TMV) have been studied in conscious sheep. A discrepancy was seen between the transient bronchoconstrictor effect (R(L) significantly increased from a base line of 1.3 ± 0.3 to 7.2 ± 21. cm H20.l-1.s immediately after challenge, and C(D) decreased from 0.06 ± 0.01 to 0.03 ± 0.01 .1. cm H20-1) and prolonged decrease in TMV (significantly depressed to a minimum of 35% of the base line during the eight hours follow-up after challenge and between 37 and 54% of base line for the following seven days) after antigen inhalation. A control challenge with ragweed extract failed to induce similar alterations. Acute (two hours) exposure to different 03 concentration showed an effect on R(L) which was dose-dependent and significant after 24 hours with 1 ppm of 03 (from a base line of 1.3 ± 0.4 to 3.0 ± 0.3 cmH20.l-1 .s 24 hours following exposure) and a significant decrease in TMV immediately after and two hours following exposure to 1 ppm (65 and 60% of the base line respectively). Preliminary results also show that repeated exposures for longer periods (four consecutive days, five hours per day) to 1 ppm of 03 also decrease TMV during the first and second day (to 66 and 37% of the base line), but during the following days of exposure adaptation takes place (TMV ranging from 55 to 68% of base line). TMV is still decreased (57% of initial base line) five days after the last exposure. We conclude that the functional effects of anaphylactic and inflammatory stimuli on the bronchi are distinct, leading to the hypothesis of different mediators and/or pathways and suggesting possibly different modes of prevention or therapy.
|Original language||English (US)|
|Number of pages||8|
|Journal||European Journal of Respiratory Diseases|
|Issue number||SUPPL. 126|
|State||Published - Jan 1 1983|
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine