9360662 Bakthavachalam During this project, fluorescent probes selective for the newly identified D-3 dopamine receptor (DA) will be developed. Since its discovery, the D-3 receptor is recognized as a member of the D-2 Like family of DA receptors and is considered to be a possible site of action of antipsychotics. Recently, 7-hydroxy-2- (N,N-dipropyl)aminotetralin (7-OH-DPAT) was identified as a potent and selective ligand for D-3 receptors. Fluorescently labeled analogs of 7-OH-DPAT will be prepared by functionalization of one of the propyl chains of 7-OH-DPAT followed by coupling with fluorescent reagents. The affinity of these probes for D-3 receptors will be determined in binding assays using membranes from CCL 1.3 fibroblasts that express cloned D-3 receptors. Selectivities of the probes will also be determined by assaying their affinities D-1 and D-2 receptors. The abilities of the most promising probes to selectively label D- 3 receptors in the CCL 1.3 fibroblasts will then be established by fluorescence microscopic studies. The fluorescent probes are expected to be useful tools for the studies of D-3 DA receptors including their localization and distribution in mammalian brain. ***
