Beta-endorphin-(1-27) is a naturally occurring antagonist to etorphine-induced analgesia.
The potent opioid peptide beta-endorphin is found in the brain and pituitary with two related fragments, beta-endorphin-(1-27) and beta-endorphin-(1-26). The fragments retain substantial opioid-receptor binding activity but are virtually inactive analgesically. beta-Endorphin-(1-27) inhibits beta-endorphin-induced and etorphine-induced analgesia when coinjected intracerebroventricularly into mice. Antagonism by competition at the same site(s) is suggested from parallel shifts of the dose-response curves of etorphine or beta-endorphin in the presence of beta-endorphin-(1-27). Its potency is 4-5 times greater than that of the opiate antagonist naloxone. beta-Endorphin-(1-26) does not antagonize the antinociceptive action of etorphine or beta-endorphin in doses up to 500 pmol per animal.
ACESSO AO ARTIGOhttp://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=397738
- beta-endorphin-(1-27) is an antagonist of beta-endorphin analgesia.
- beta-Endorphin-induced analgesia is inhibited by synthetic analogs of beta-endorphin.
- Peptide inhibitor of morphine- and beta-endorphin-induced analgesia.
- Beta-endorphin: opiate receptor binding activities of six naturally occurring beta-endorphin homologs studied by using tritiated human hormone and naloxone as primary ligands--effects of sodium ion.
- beta-endorphin is a potent analgesic agent.