title: 125I-DPDYN, monoiodo[D-Pro10]dynorphin(1-11): a highly radioactive and selective probe for the study of kappa opioid receptors.
abstract: The mono- and diiodinated derivatives of the kappa-selective ligand [D-Pro10]dynorphin(1-11), DPDYN, were prepared. Their binding properties at the three opioid receptor types (mu, delta and kappa) were examined and compared to those of the parent peptide. The monoiodo derivative shows a general although moderate decrease in affinity and retains high kappa selectivity (KI mu/KI kappa = 48 and KI delta/KI kappa = 140). The binding properties of the diiodo derivative are found to be dramatically decreased. Radioiodination of DPDYN leads to the monoiodinated peptide with high specific activity (700-800 Ci/mmol). In guinea-pig cerebellum membranes, a kappa-specific tissue, [125I]-labelled monoiodo[D-Pro10]dynorphin(1-11), 125I-DPDYN, interacts specifically and reversibly with a single class of binding sites (Bmax = 118 fmol/mg protein) with a high affinity (KD = 0.12 nM from equilibrium experiments, 0.18 nM from kinetics studies). Therefore, because of its high specific radioactivity, high affinity and reasonably good selectivity, 125I-DPDYN designates itself as the probe of the k-opioid receptor type.
authors.forename: J E
authors.initials: JE
authors.lastname: Gairin
authors.forename: C
authors.initials: C
authors.lastname: Jomary
authors.forename: L
authors.initials: L
authors.lastname: Pradayrol
authors.forename: J
authors.initials: J
authors.lastname: Cros
authors.forename: J C
authors.initials: JC
authors.lastname: Meunier
mesh_terms: D000818:Animals; D002531:Cerebellum / Q000378:metabolism; D004399:Dynorphins; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007457:Iodine Radioisotopes; D007553:Isotope Labeling; D007700:Kinetics; D008297:Male; D010446:Peptide Fragments; D011869:Radioligand Assay; D051381:Rats; D011919:Rats, Inbred Strains; D011957:Receptors, Opioid / Q000378:metabolism*; D017473:Receptors, Opioid, kappa
chemical_list: D007457:Iodine Radioisotopes; D010446:Peptide Fragments; D011957:Receptors, Opioid; D017473:Receptors, Opioid, kappa; D004399:Dynorphins; C044619:dynorphin (1-11), Pro(10)-