title: Target-specific ligands and gadolinium-based complexes for imaging of dopamine receptors: synthesis, binding affinity, and relaxivity.
abstract: Magnetic resonance imaging (MRI) and positron emission tomography (PET) are two extremely important imaging modalities with unlimited tissue penetration. Molecular imaging is a field by which specific targets or biological processes are imaged. MRI, which is used for functional imaging and for the diagnosis of a broad range of pathologic conditions, suffers from limited specificity and intrinsically low sensitivity. One possibility to alleviate partially these limitations is to use contrast agents (CAs) and more importantly target-specific CAs. We have developed a modular synthesis of novel ligands and gadolinium(III)-based target-specific MRI CAs with high relaxivity and high binding affinity toward the dopamine receptors. The prepared ligands and MRI CAs are based on spiperone as targeting moiety. The prepared target-specific CAs can potentially be used for in vitro and possibly in vivo MR imaging of dopaminergic receptors. Importantly the ligands prepared using the modular approach presented in this paper may also be useful for other imaging modalities such as PET (or SPECT) by just replacing, at the last stage of the synthesis, the gadolinium cation by other metal cations having relatively long half-lives, such as (64)Cu, (89)Zr, (11)In, and more.
authors.affiliation: School of Chemistry, the Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, Tel-Aviv 69978, Israel.
authors.forename: Isaac
authors.initials: I
authors.lastname: Zigelboim
authors.forename: Avi
authors.initials: A
authors.lastname: Weissberg
authors.forename: Yoram
authors.initials: Y
authors.lastname: Cohen
mesh_terms: D001665:Binding Sites / Q000187:drug effects; D065127:Dopamine D2 Receptor Antagonists; D005682:Gadolinium / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D008024:Ligands; D008279:Magnetic Resonance Imaging; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D049268:Positron-Emission Tomography; D017448:Receptors, Dopamine D2 / Q000737:chemistry; D050637:Receptors, Dopamine D3 / Q000037:antagonists & inhibitors* / Q000737:chemistry; D013329:Structure-Activity Relationship
chemical_list: D065127:Dopamine D2 Receptor Antagonists; D008024:Ligands; D009942:Organometallic Compounds; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D005682:Gadolinium