Effect of human B-endorphin on the binding of different opiates to mouse brain membranes.
The competition of human B-endorphin (B-EP) for dihydromorphine (DHM) and D-Ala2-D-Leu5-enkephalin (DADLE) binding sites has been studied at three temperatures, 0 degree, 25 degrees, and 37 degrees C. B-EP is more effective in inhibiting mu and delta binding at 0 degree and 25 degrees than at 37 degrees C. This difference does not seem related to a temperature-dependent degradation of the peptide. DHM and DADLE high affinity binding sites are clearly distinguished by B-EP. The high affinity site for DHM and the low of DADLE are the more easily displaced by B-EP, but with different affinities. These sites are different in binding capacities, although distinct stoichiometric ratios of binding or the existence of isoreceptors could account for their identity.
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D004723:Endorphins / Q000494:pharmacology*; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives / Q000378:metabolism; D016308:Enkephalin, Leucine-2-Alanine / Q000031:analogs & derivatives*; D006801:Humans; D007700:Kinetics; D051379:Mice; D011957:Receptors, Opioid / Q000187:drug effects / Q000378:metabolism*; D001615:beta-Endorphin
D004723:Endorphins; D011957:Receptors, Opioid; D004743:Enkephalin, Leucine; D001615:beta-Endorphin; D016308:Enkephalin, Leucine-2-Alanine; C030279:enkephalinamide-Leu, Ala(2)-