Opiate and peptide interaction: effect of enkephalins on morphine analgesia.
Interactions between the weakly analgesic enkephalins and morphine on morphine-induced analgesia were studied. Met-enkephalin exhibited morphine analgesia whereas Leu-enkephalin potentiated it. Both Met- and Leu-enkephalin, when tested alone, were not analgesic. The strongly analgesic FK33824 (Sandoz) compound, like Leu-enkephalin, also potentiated morphine analgesia. Tolerance developed to morphine analgesia but not to Met-enkephalin inhibition of morphine analgesia.
D000698:Analgesia; D000818:Animals; D001667:Binding, Competitive; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004361:Drug Tolerance; D004723:Endorphins / Q000494:pharmacology*; D004745:Enkephalins / Q000494:pharmacology*; D008297:Male; D051379:Mice; D009020:Morphine / Q000494:pharmacology*; D011957:Receptors, Opioid / Q000187:drug effects
D004723:Endorphins; D004745:Enkephalins; D011957:Receptors, Opioid; D009020:Morphine