An approach for assaying benzodiazepine receptor binding with radioiodinated ligand: 125I-labeled diazepam derivative.
[125I]2'-Iododiazepam (IDZ) was prepared and its application in a benzodiazepine receptor binding assay was studied. [125I]2'-IDZ binds to the rat cortical membrane with a high affinity (Kd, 0.66 nM). Various benzodiazepines showed competition with [125I]2'-IDZ for the binding sites in the rat cortical membrane, and the specificity of its binding correlated well with that of [3H]diazepam (r = 0.992, p < 0.001). These findings suggested that [125I]2'-IDZ binds to the same sites as [3H]diazepam and indicated that [125I]2'-IDZ can be used in a benzodiazepine receptor assay.
Department of Radiopharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Kyoto University, Japan.
H
H
Saji
Y
Y
Iida
K
K
Ariyoshi
I
I
Nakatsuka
M
M
Kataoka
A
A
Yoshitake
A
A
Yokoyama
D000818:Animals; D001569:Benzodiazepines / Q000494:pharmacology; D001667:Binding, Competitive / Q000187:drug effects; D002540:Cerebral Cortex / Q000378:metabolism; D003975:Diazepam / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000493:pharmacokinetics / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D007457:Iodine Radioisotopes; D007553:Isotope Labeling; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000378:metabolism*; D013696:Temperature
D007457:Iodine Radioisotopes; D011963:Receptors, GABA-A; C081585:2'-iododiazepam; D001569:Benzodiazepines; D003975:Diazepam