title: [Binding of a tritiated enkephalinergic analog (FK 33-824) to a mitochondrial fraction of rat brain].
abstract: FK-33-824 (Try-D-Ala-Gly-MePhe-Met(O)ol) is a potent enkephalin analog which has been tritium labelled with a high specific radioactivity (41 Ci/mmole). The labelled drug exhibits specific and saturable binding to rat brain crude mitochondrial fraction. Specific binding is inhibited by low concentrations of morphine, levallorphan and beta-endorphin, suggesting that FK 33-824 [3H] binds preferentially to mu opiate sites. Binding studies at equilibrium and kinetics of formation and dissociation of the labelled ligand-receptor complex indicate that FK 33-824 [3H] binds to two classes of specific sites. Their affinities are distinguishable at 0 degree (KD = 1.3 and 5.8 nM) and very close to each other at 37 degree (KD = 1.9 nM).
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D005405:D-Ala(2),MePhe(4),Met(0)-ol-enkephalin; D004723:Endorphins / Q000378:metabolism* / Q000494:pharmacology; D004745:Enkephalins / Q000378:metabolism*; D007700:Kinetics; D007977:Levallorphan / Q000494:pharmacology; D008928:Mitochondria / Q000378:metabolism*; D009020:Morphine / Q000494:pharmacology; D010215:Papio; D051381:Rats; D001615:beta-Endorphin
chemical_list: D004723:Endorphins; D004745:Enkephalins; D007977:Levallorphan; D001615:beta-Endorphin; D005405:D-Ala(2),MePhe(4),Met(0)-ol-enkephalin; D009020:Morphine
vernacular_title: Liaison d'un analogue enképhalinergique [FK 33-824] tritié à une fraction mitochondriale de cerveau de rat.