Abstract
Asthma is a clinical syndrome manifested by reversible and intermittent obstruction of the bronchi.
The reported incidence of aspirin-induced asthma varies from 2.3 to 20.0% and is the highest of all drug-induced asthma. Nevertheless the etiology of aspirin-induced asthma is unknown.
We suggested that contractile responses of guinea pig tracheal tissues with histamine, serotonin, prostaglandin F2α and bradykinin were increased with continuous infusion of aspirin, continuing to increase with larger doses of aspirin.
The present investigation was conducted to explore the effect of aspirin on the relaxation of guinea pig tracheal tissues with various bronchodilators.
Male guinea pigs, weighing 250-300g, were killed. Guinea pig tracheal tissues were removed and suspended in bioassay glass jackets and superfused with Krebs-Henseleit solution at 37°C, saturated with oxygen and carbon dioxide (95:5, v/v).
Relaxation of tissues was detected by an isotonic transducer and displayed on a polyrecorder.
1) Bronchodilating effects of isoproterenol and salbutamol were increased with continuous infusion of aspirin at a dose of 5×10-8M and decreased dose-dependently with increasing doses of aspirin.
2) Bronchodilating effects of adrenaline, aminophylline and prostaglandin E2 markedly decreased with continuous infusion of aspirin, and became even smaller by increasing the dose of aspirin.
3) These results suggest that aspirin has an attenuating effect on the actions of bronchodilators, besides a potentiating effect on the action of bronchoconstrictors, and that such a mechanism may play an important role in the pathophysiological aspects of aspirin-induced asthma.
