Regulation of peripheral-type benzodiazepine receptors in cultured astrocytes by monoamine and amino acid neurotransmitters.
Exposure of primary cultured astrocytes for 3 days to 1 microM of either dopamine, serotonin or norepinephrine resulted in upregulation (25-34% increase in Bmax) of the peripheral-type benzodiazepine receptors (PBRs) labeled with [3H]Ro5-4864. A similar treatment with gamma-aminobutyric acid [GABA] caused a 2-fold increase in the affinity (Kd) of [3H]Ro5-4864. The monoamines tested and GABA had no effect on the binding parameters of [3H]PK 11195, another selective PBR ligand. The present study indicates that Ro5-4864 binding sites are susceptible to regulation by specific neurotransmitters and provides further evidence for the distinction between Ro5-4864 and PK 11195 binding sites of the PBRs in cultured astrocytes.
Itzhak
Y
Y
Department of Biochemistry and Molecular Biology (R-629), University of Miami School of Medicine, FL 33101.
Norenberg
M D
MD
D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000378:metabolism*; D001570:Benzodiazepinones / Q000378:metabolism; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000378:metabolism*; D003292:Convulsants / Q000378:metabolism; D004298:Dopamine / Q000494:pharmacology*; D007546:Isoquinolines / Q000378:metabolism; D007700:Kinetics; D009638:Norepinephrine / Q000494:pharmacology*; D051381:Rats; D011916:Rats, Inbred F344; D011963:Receptors, GABA-A / Q000187:drug effects / Q000378:metabolism*; D012701:Serotonin / Q000494:pharmacology*; D015854:Up-Regulation / Q000187:drug effects; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D001570:Benzodiazepinones; D003292:Convulsants; D007546:Isoquinolines; D011963:Receptors, GABA-A; C028513:4'-chlorodiazepam; D012701:Serotonin; D005680:gamma-Aminobutyric Acid; D004298:Dopamine; D009638:Norepinephrine; C037850:PK 11195