AGONIST AND ANTAGONIST PROPERTIES OF N-ALLYL-ENKEPHALINS

  • 1 January 1977
    • journal article
    • research article
    • Vol. 18  (1) , 1-9
Abstract
The agonist (ID50 [median inhibitory dose]) and antagonist (Ke) potencies of the newly synthesized N-allyl derivatives of Met5-enkephalin and Leu5-enkephalin were compared with those of their respective parent compounds on the myenteric plexus-longitudinal muscle preparation of the guinea-pig ileum. N-allyl substitution of the amine-N in the Met5-enkephalin significantly decreased the ID50 and the Ke. Similar substitution in Leu5-enkephalin did not significantly alter the ID50, but caused an almost 10-fold increase in the Ke. Substitution on the amine-N of Leu5-enkephalin rather than Met5-enkephalin is more likely to produce potent narcotic antagonists.