[Show abstract][Hide abstract] ABSTRACT: In anesthetized guinea-pigs previously sensitized to ovalbumin by intratracheal immunization, the intravenous administration of propranolol (3.1 mg/kg) produced an increase in the respiratory insufflation pressure induced by ovalbumin. Atropine (2 mg/kg), zolertine (1 mg/kg) and indomethacin (3.1 mg/kg) did not antagonize the propranolol-induced airway hyperreactivity. Indomethacin at higher dose (10 mg/kg) and BW755c (10 mg/kg) decreased the potentiation of the respiratory insufflation pressure to ovalbumin. Our results suggest that besides the beta-blockade, propranolol-induced bronchial hyperreactivity to ovalbumin in sensitized guinea-pigs could be mediated by leukotrienes.
No preview · Article · Jan 1988 · Pharmacological Research Communications
[Show abstract][Hide abstract] ABSTRACT: Experimental asthma models in guinea pigs usually produce bronchoconstriction as part of a systemic anaphylactic reaction. Since immunization in asthmatic patients is through airborne allergens and the human crisis is localized to the airways, we developed a new model that satisfied these two criteria. Twenty-four guinea pigs were nebulized with ovalbumin (300 mg) as antigen and Bordetella pertussis vaccine as adjuvant. One week later they were nebulized with ovalbumin daily for 2 weeks and then challenged with intravenous ovalbumin at three different doses. We found the animals developed a dose-dependent bronchoconstriction without acute systemic hypotension or other signs due to an anaphylactic reaction. As control group five guinea pigs nebulized with ovalbumin alone for 3 weeks were used and only presented a small and low reproducible bronchoconstriction. We conclude that this model presents greater similarities to the human disease and has the advantage of causing localized, reproducible and graduated bronchoconstrictive response.