Differential localization of GABA-dependent and GABA-independent benzodiazepine binding sites within synapses of rat cerebral cortex.
Fractions containing non-junctional membranes (fraction 1) could be separated from those enriched in junctional complexes (fraction 2) by sucrose gradient centrifugation of osmotically disrupted rat cerebral cortex synaptosomes. [3H]flunitrazepam binding sites were found to be homogeneous characterized by Kd = 0.65 nM, Bmax = 13 pM for fraction 1; and Kd = 2 nM, Bmax = 45 pM for fraction 2. GABA-dependent benzodiazepine receptor sites were found to be localized to the junctional complex fraction, while non-junctional membranes showed GABA-independent receptor and acceptor binding sites.
D000818:Animals; D001569:Benzodiazepines / Q000378:metabolism*; D002540:Cerebral Cortex / Q000378:metabolism*; D005445:Flunitrazepam / Q000378:metabolism; D007700:Kinetics; D008854:Microscopy, Electron; D051381:Rats; D011963:Receptors, GABA-A / Q000187:drug effects / Q000378:metabolism*; D013569:Synapses / Q000378:metabolism* / Q000648:ultrastructure; D013574:Synaptosomes / Q000378:metabolism / Q000648:ultrastructure; D005680:gamma-Aminobutyric Acid / Q000378:metabolism / Q000494:pharmacology*
D011963:Receptors, GABA-A; D001569:Benzodiazepines; D005680:gamma-Aminobutyric Acid; D005445:Flunitrazepam