Benzodiazepine receptors in human brain: characterization, subcellular localization and solubilization.
1. Benzodiazepine receptors have been characterized in human brain mainly using [3H]-Ro 15-1788 and [3H]-flunitrazepam. Both ligands present a very high affinity for the receptor sites (Kd values of 0.56 and 1.53 nM respectively). 2. GABA enhanced the affinity of [3H]-flunitrazepam and [3H]-diazepam, but not that of [3H]-Ro 15-1788 and [3H]-methyl-beta-carboline 3-carboxylate for their specific binding sites as well in cerebral as in cerebellar human cortex. 3. Subcellular distribution of the benzodiazepine receptors revealed a main synaptosomal localization in human cerebral cortex, cerebellum and striatum. 4. Solubilized benzodiazepine receptors were obtained using 0.5% sodium deoxycholate and were characterized with [3H]-Ro 15-1788. The solubilized receptors are still coupled to GABA receptors since the [3H]-flunitrazepam specific binding was enhanced in the presence of micromolar concentrations of GABA.
Maloteaux
J M
JM
Université Catholique de Louvain, Laboratoire de Neurochimie Brussels, Belgium.
Octave
J N
JN
Vanisberg
M A
MA
Kollmann
P
P
Ackermans
A
A
Laterre
C
C
D001921:Brain / Q000378:metabolism*; D005445:Flunitrazepam / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D009928:Organ Specificity; D011963:Receptors, GABA-A / Q000302:isolation & purification / Q000378:metabolism*; D012995:Solubility; D013347:Subcellular Fractions / Q000378:metabolism
D011963:Receptors, GABA-A; D005445:Flunitrazepam