| Popis: |
4-Amino-N-[1-[3-(4-fluorophenoxy)propyl]-4-methyl-4-piperidinyl]-2-methoxy-benzamide, a compound with high affinity for 5HT2-receptors, was radioiodinated on the 2-position of the phenoxygroup or the 5-position of the methoxybenzamide group. The former (obtained by Cu1+-assisted radioiodo for bromo exchange) showed high lipophilicity and high non-specific binding to rat brain tissue both in vitro and in vivo. The second labelled compound, 125I-4-amino-N-[1-[3-(4-fluorophenoxy)propyl]-4-methyl-4-piperidinyl]-5-iodo-2-methoxybenza-mide, obtained by direct electrophilic substitution, showed high affinity (Kd of 0.11 ± 0.01 nM) and marked selectivity for 5HT2-receptors in vitro. Moreover in vivo studies in rats over the course of 1-3 hrs post i.v. injection of the radioactive ligand, showed steady preferential retention of radioactivity in the frontal cortex, which is enriched in 5HT2 receptors. (Frontal cortex (FC) / Cerebellum ratio of 10 and FC / Blood ratio of 6, amount compound / mg tissue). |
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