Recent studies of 5-HT2 receptor binding have involved the use of radiolabeled agonists. This report describes the use of [125I]-2-(2,5-dimethoxy-4-iodophenyl)aminoethane ([125I]-2C-I) as a label for low-density 5-HT2 agonist binding sites. A nonhydrolyzable analog of GTP, GppNHp, was found to inhibit the high affinity binding of [125I]-2C-I. 5-HT and several 5-HT2 agonists and antagonists...
R(-)-2,5-Dimethoxy-4-77Br-amphetamine [77Br-R(-)DOB], a radioligand of high specific activity (1500 +/- 200 Ci/mmol), was used to label membrane-associated recognition sites in rat brain. 77Br-R(-)DOB sites were of high affinity (KD = 0.19 nM) but low density (Bmax = 0.32 pmol/g tissue) in rat brain preparations. Competition experiments show that both 5-hydroxytryptamine (5-HT) and 5-HT2...