[125I][D-Ala2]deltorphin-I: a high affinity, delta-selective opioid receptor ligand.
The selective delta opioid agonist [D-Ala2]deltorphin-I was radioiodinated and the product purified using reverse phase HPLC. The binding characteristics and distribution profile of [125I][D-Ala2]deltorphin-I were assessed in mouse brain using homogenate binding techniques and quantitative autoradiography. [125I][D-Ala2]deltorphin-I bound with high affinity to a single class of sites (KD = 0.5 nM) in brain membrane preparations and striatal sections. Competition studies indicated that [125I][D-Ala2]deltorphin-I was selectively labeling delta opioid receptors as shown by the ratio of apparent affinities for mu and delta receptors (KI mu/KI delta = 1388). The autoradiographical distribution profile of [125I][D-Ala2]deltorphin-I binding sites was also consistent with that of other delta-selective radioligands. The data indicate that [125I][D-Ala2]deltorphin-I binds to delta opioid receptors with high affinity and selectivity. Because of its very high specific activity, it can be detected rapidly with high sensitivity by autoradiographic emulsion.
Dupin
S
S
Laboratoire de Pharmacologie et de Toxicologie Fondamentales, CNRS, Toulouse, France.
Tafani
J A
JA
Mazarguil
H
H
Zajac
J M
JM
D000595:Amino Acid Sequence; D000818:Animals; D001345:Autoradiography; D001921:Brain / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D005405:D-Ala(2),MePhe(4),Met(0)-ol-enkephalin / Q000037:antagonists & inhibitors / Q000378:metabolism; D004745:Enkephalins / Q000494:pharmacology; D007457:Iodine Radioisotopes; D008024:Ligands; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000378:metabolism*; D011957:Receptors, Opioid / Q000378:metabolism*; D017465:Receptors, Opioid, delta; D013379:Substrate Specificity
D004745:Enkephalins; D007457:Iodine Radioisotopes; D008024:Ligands; D009842:Oligopeptides; D011957:Receptors, Opioid; D017465:Receptors, Opioid, delta; C060208:deltorphin I, Ala(2)-; D005405:D-Ala(2),MePhe(4),Met(0)-ol-enkephalin