Suppressive effect of clenbuterol on citric acid-induced cough reflex in guinea pigs.

We previously demonstrated that clenbuterol suppressed bronchial hyperresponsiveness in acute bronchitic models. However the effect of clenbuterol on the cough reflex, the main symptom of acute bronchitis, is not clear. The present study was thus undertaken to investigate the influence of clenbuterol on the cough reflex.

Effect of clenbuterol on sulfur dioxide-induced acute bronchitis in guinea pigs.

When guinea pigs were exposed to sulfur dioxide (SO2) gas (800 ppm, 2 h), they showed hyperresponsiveness to intravenously administered serotonin (5-hydroxytryptamine (5-HT)). This hyperresponsiveness continued for over 24 h after the exposure to the gas. The degeneration, desquamation of epithelium, and edema of the lamina propria of the trachea and bronchi were observed in animals after a 2-h exposure of SO2 histopathologically.