ATTENUATION OF ANTIGEN-INDUCED BRONCHOSPASM BY FENOTEROL IN THE GUINEA-PIG

Abstract

When guinea-pigs sensitized to ovalbumin were challenged with ovalbumin, the histamine concentrations in lung tissue decreased, whereas those in tracheal and heart tissues increased during the 15 min following challenge. Fenoterol (2.5 mg/kg, i.p.), administered 30 min prior to challenge, attenuated both the decrease and the increase in lung and tracheal histamine concentrations, respectively. The challenge-induced increase in heart histamine was also prevented. In the anaesthetized guinea-pig, a marked increase in intratracheal pressure (ITP) occurred on challenge. This was of longer latency than the increase in ITP induced by histamine and was consistent with a release process. Treatment o..