The role of peripheral benzodiazepine receptors (PBRs) in CNS pathophysiology

The peripheral benzodiazepine receptors (PBRs) have been identified to bind selectively benzodiazepine ligands and an isoquinoline carboxamide derivative PK 11195 with high affinity. PBRs are present in the central nervous system (CNS), peripheral tissues, and most organs in the human body. PBRs are different from the central benzodiazepine receptors (CBRs) related to the nerve cell membrane GABA(A) receptor and are thought to play several physiological and pathophysiological functions in the CNS and immune system due to their meanly localization in glial cells, the mitochondrial outer membrane of peripheral cells and blood leucocytes and to their important roles in steroidogenesis, cell proliferation and differentiation. Recent research has shown that the density of PBRs is significanly increased in CNS several disorders, such as epilepsy, multiple sclerosis, cerebral ischemia, astrocytoma, brain injury and neurodegenerative diseases. Recent progress in the pharmacology of PBRs is reviewed here with respect to the functions in the brain and peripheral tissues including apoptosis, immune system modulation, seizure promotion, reactions of anticonvulsants on peripheral blood cells, and adverse drug reactions (ADR) of anticonvulsants.