Opioid peptides and their receptors.
The three agonists, methionine-enkephalin, leucine-enkephalin and beta-endorphin have different pharmacological patterns. It may be of particular importance that they vary in their relative affinities to the enkephalin and naltrexone binding sites in the brain; the former are probably related to delta-receptors prevalent in the mouse vas deferens and the later to mu-receptors prevalent in the guinea-pig. It is possible that mu-receptors are more important for the mediation of analgesic effects than delta-receptors. An understanding of the pharmacokinetics of the opioid peptides will be of basic importance for the design of enkephalin analogues suitable for use as analgesics in man.
D000818:Animals; D001921:Brain / Q000378:metabolism; D004285:Dogs; D004723:Endorphins / Q000378:metabolism*; D004745:Enkephalins / Q000378:metabolism; D006168:Guinea Pigs; D007082:Ileum / Q000378:metabolism; D008297:Male; D051379:Mice; D009270:Naloxone / Q000378:metabolism; D009271:Naltrexone / Q000378:metabolism; D011957:Receptors, Opioid / Q000378:metabolism*; D014649:Vas Deferens / Q000378:metabolism
D004723:Endorphins; D004745:Enkephalins; D011957:Receptors, Opioid; D009270:Naloxone; D009271:Naltrexone