Antagonism of 5-hydroxytryptamine-induced bronchospasm in guinea-pigs by 8β-carbobenzyloxy-aminomethyl-1-methyl-10α-ergoline

Abstract

The drug 8β-carbobenzyloxyaminomethyl-1-methyl-10α-ergoline (mce) has been shown to have a potent and prolonged antagonism to 5-hydroxytryptamine-induced bronchospasm in guinea-pigs. 4–5 hr after 2 μg/kg of mce, given intraveneously, the effects of the 5-ht were still markedly inhibited (dose ratio more than 1:300). A subcutaneous dose of 150 μg/kg of the drug partially counteracted the effects of 5-ht for 4–7 days. Comparison between mce and l-methyl-(+)-lysergic acid butanolamide tartrate (methysergide, uml 491) revealed that the antagonism to 5-ht by mce developed more slowly but lasted longer than that elicited by methysergide. The results show that mce is a specific antagonist of 5-ht-induced bronchospasm in guinea-pigs as it does not antagonise the bronchospasm-inducing effects of acetylcholine, histamine and eledoisin.