[Antitussive effects of Bakumondô-tô and codeine in bronchitic guinea-pigs]

Antitussive effects of Bakumondô-tô and codeine were examined in bronchitic guinea-pigs made by an exposure to SO2. Bakumondô-tô significantly depressed the cough reflex induced by mechanical and chemical stimulations in the bronchitic but not in the normal animals. Repeated administration of Bakumondô-tô significantly suppressed the increased spontaneous discharge of the superior laryngeal nerve in bronchitic animals. On the other hand, the antitussive action of codeine in bronchitic animals was significantly weaker than that in normal animals. Moreover, repeated administrations of codeine significantly potentiated the increased spontaneous discharge of the superior laryngeal nerve. The results suggest that Bakumondô-tô, unlike codeine, has a notable antitussive activity in bronchitic rather than in normal guinea-pigs.