title: Peptide inhibitor of morphine- and beta-endorphin-induced analgesia.
abstract: The synthetic beta-endorphin analogs with the omission of the NH2-terminal [Met]enkephalin segment [beta-endorphin-(6-31) and beta-endorphin-(20-31)] are shown to inhibit morphine- or beta-endorphin-induced analgesia in mice by the tail-flick test, whereas the synthetic NH2-terminal pentadecapeptide beta-endorphin-(1-15) has no inhibitory activity. This study raises the possibility that endogenous inhibiting peptides exist in the brain which play a role in the regulation of endorphin actions.
mesh_terms: D000595:Amino Acid Sequence; D000700:Analgesics / Q000037:antagonists & inhibitors*; D000818:Animals; D004723:Endorphins / Q000037:antagonists & inhibitors* / Q000138:chemical synthesis / Q000494:pharmacology*; D008297:Male; D051379:Mice; D009020:Morphine / Q000037:antagonists & inhibitors*; D013329:Structure-Activity Relationship; D001615:beta-Endorphin
chemical_list: D000700:Analgesics; D004723:Endorphins; D001615:beta-Endorphin; D009020:Morphine