Binding properties of the pure opioid antagonist [3H](N-propyl)-noroxymorphone in rat brain membranes.
(-)[N-(propyl)-14-OH-dihydromorphinan-6-one] = (N-propyl)-noroxymorphone and its multiple tritiated form (molar activity: 126 Ci/mmol; 1 Ci = 37 GBq) was synthesized. According to our knowledge this specific radioactivity exceeds all of the commercially available [3H]opioid ligands. The ligand was found to be a pure opioid antagonist in receptor binding assays performed with rat brain membranes. Scatchard analysis of equilibrium binding isotherms revealed one high affinity (Kd approximately 4 nM) binding site. Reversibility, stereospecificity and opioid nature of the binding was confirmed by ligand binding experiments. Because of its antagonist character combined with high specific radioactivity the ligand might be a useful tool in characterizing and purifying opioid receptors.
Tóth
G
G
Isotope Laboratory, Hungarian Academy of Sciences, Szeged.
Benyhe
S
S
Hosztafi
S
S
Borsodi
A
A
D000818:Animals; D001921:Brain / Q000378:metabolism*; D066298:In Vitro Techniques; D008566:Membranes / Q000378:metabolism; D009019:Morphinans / Q000493:pharmacokinetics*; D009292:Narcotic Antagonists / Q000493:pharmacokinetics*; D011869:Radioligand Assay; D051381:Rats; D011919:Rats, Inbred Strains; D011957:Receptors, Opioid / Q000378:metabolism*
D009019:Morphinans; D009292:Narcotic Antagonists; D011957:Receptors, Opioid; C089092:N-propyl-noroxymorphone