title: Photolabile opioid derivatives of D-Ala2-Leu5-enkephalin and their interactions with the opiate receptor.
abstract: Photolabile derivatives of D-Ala2-Leu5-enkephalin were prepared by synthetic procedures in which a 2-nitro-4-azidophenyl group is linked to the terminal carboxyl group of the enkephalin by means of an ethylenediamine or ethylenediamine beta-alanine spacer. These peptides bind to opiate receptors with nanomolar affinities and inhibit electrically stimulated contractions of the mouse vas deferens and adenylate cyclase activity of NG108-15 neuroblastoma x glioma hybrid cell membranes. Both inhibitions are reversed by the opiate antagonist naloxone. Photolysis of the ligands bound to rat brain membranes results in the loss of approximately 50% of the receptor sites. This decrease in receptor number is blocked by naloxone and requires light. A photolabile [3H]enkephalin derivative labels an equivalent number of sites under similar irradiation conditions.
mesh_terms: D000818:Animals; D001681:Biological Assay; D001921:Brain / Q000378:metabolism; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D016308:Enkephalin, Leucine-2-Alanine; D008297:Male; D051379:Mice; D009119:Muscle Contraction / Q000187:drug effects; D010782:Photolysis; D051381:Rats; D011957:Receptors, Opioid / Q000378:metabolism*; D014649:Vas Deferens / Q000187:drug effects
chemical_list: D011957:Receptors, Opioid; D004743:Enkephalin, Leucine; D016308:Enkephalin, Leucine-2-Alanine