Murexine or urocanylcholine is a naturally occurring choline ester of urocanic acid which was found in very large amounts in the hypobranchial body of Murex trunculus and other prosobranchiate molluscs. In vertebrates and invertebrates, it was found to possess marked neuromuscular blocking and nicotinic actions, but was almost devoid of muscarinic effects. The blocking action of murexine was considered, on the basis of experimental and clinical evidence, to be of the " depolarizing" type. It was weaker than, but qualitatively very similar to, that produced by suxamethonium. The nicotinic action of murexine was stronger than that of suxamethonium in both experimental animals and human beings.Murexine or urocanyicholine (fi-[imidazole-4(5)]-acryl-choline) is a naturally occurring choline ester found in the hypobranchial body of some prosobranchiate molluscs, which might use it for defence or, more likely, for procuring food.
A new series of eledoisin-like peptides was synthesized with the object of obtaining long-lasting hypotensive drugs. Acyl residues were introduced into the molecule of the peptide R
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.
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