Identification of a red-emitting fluorescent ligand for in vitro visualization of human serotonin 5-HT1A receptors

The 5-HT1A receptor subtype is the most thoroughly studied serotonin receptor subtype. We report here the design, synthesis and characterization of two new fluorescent ligands for the 5-HT1A receptor. The new 1-arylpiperazine-based red-emitting fluorescent compound 6 displayed good binding affinity at the 5-HT1A receptor (Ki = 35 nM) and was able to label specifically the human 5-HT1A receptor stably expressed in CHO cells visualized using confocal laser scanning microscopy.