Brain kinetics and specific binding of [11C]PK 11195 to ω3 sites in baboons: positron emission tomography study

11C-AC-5216: A Novel PET Ligand for Peripheral Benzodiazepine Receptors in the Primate Brain

“…PBR is mainly located in the glial cells of the brain, and PBR expression in vivo was found to be increased in microglia activated by brain injury (6,7). The increase in PBR density has thus been used as an indicator of neuronal damage and neurodenerative disorders, such as Alzheimer's disease (6)(7)(8)(9)(10)(11)(12). These findings have prompted the development of an imaging agent labeled with a radioisotope, which has made it possible to visualize the distribution of PBR in the animal brain, including the human brain (13)(14)(15)(16).…”

“…11 C-PK11195, a positron emitter-labeled ligand, was first developed to characterize PBR in the human brain (13,18). However, the relatively low uptake of 11 C-PK11195 in the brain limited its wide application (11,19).…”

“…11 C-PK11195, a positron emitter-labeled ligand, was first developed to characterize PBR in the human brain (13,18). However, the relatively low uptake of 11 C-PK11195 in the brain limited its wide application (11,19). To characterize PBR precisely using a PET ligand with advantages over 11 C-PK11195, we developed 2 novel ligands, 11 C-DAA1106 (20,21) and 18 F-FEDAA1106 (22), for PBR imaging in the brain.…”

“…However, the relatively low uptake of 11 C-PK11195 in the brain limited its wide application (11,19). To characterize PBR precisely using a PET ligand with advantages over 11 C-PK11195, we developed 2 novel ligands, 11 C-DAA1106 (20,21) and 18 F-FEDAA1106 (22), for PBR imaging in the brain. These ligands exhibited more potent in vitro binding affinity for PBR than PK11195 and displayed remarkable selectivity against other receptors, including CBR (22)(23)(24).…”

Microglial positron emission tomography (PET) imaging in epilepsy: Applications, opportunities and pitfalls

“…Firstly, PK11195 is highly lipophilic and shows a high level of non-specific binding (e.g. to brain fat) [27]. By increasing the background non-specific signal, this reduces the signal to noise ratio (Box 2).…”