title: Ontogenesis of delta-opioid receptors in rat brain using [3H][D-Pen2,D-Pen5]enkephalin as a binding ligand.
abstract: The ontogenesis of delta-opioid receptors has been studied in the postnatal period up to day 50 using the highly selective delta-site ligand [3H][D-Pen2,D-Pen5]enkephalin ([3H]DPDPE) in binding studies. Analyses of saturation curves revealed marked increases in binding capacities between the second and fourth postnatal week with little change in affinity. In contrast to findings with [3H][D-Ala2,D-Leu5]enkephalin binding could not be detected before postnatal day 10 which may be associated with the low affinity and specific activity of DPDPE. A low specific binding for [3H]DPDPE poses methodological problems in the use of this ligand for ontogenic studies.
mesh_terms: D000818:Animals; D001921:Brain / Q000254:growth & development* / Q000378:metabolism; D020881:Enkephalin, D-Penicillamine (2,5)-; D004745:Enkephalins / Q000494:pharmacology*; D005260:Female; D007700:Kinetics; D008024:Ligands; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011957:Receptors, Opioid / Q000378:metabolism*; D017465:Receptors, Opioid, delta
chemical_list: D004745:Enkephalins; D008024:Ligands; D011957:Receptors, Opioid; D017465:Receptors, Opioid, delta; D020881:Enkephalin, D-Penicillamine (2,5)-