Synthesis and pharmacological characterization of the selective GluK1 radioligand (S)-2-amino-3-(6-[3H]-2,4-dioxo-3,4-dihydrothieno[3,2-d]pyrimidin-1(2H)-yl)propanoic acid ([3H]-NF608)
The kainic acid receptors belong to the class of ionotropic glutamate receptors and comprise five subunits named GluK1–5. Radioligands are essential tools for use in binding assays aimed at ligand–receptor structure–activity-relationship studies. Previous work has led to the synthesis of GluK1 radioligands [3H]-SYM2081, [3H]-UBP310 and [3H]-ATPA, however all strategies were work-intensive and thus not attractive. Herein, we report the synthesis of [3H]-NF608 and subsequent pharmacological evaluation at homomeric recombinant rat GluK1 receptors. Binding affinities of a series of standard GluK1 ligands were shown to be in line with previously reported affinities obtained by use of already reported radioligands.