A quantitative relationship between Cl- enhanced [3H]flunitrazepam and [35S]t-butylbicyclophosphorothionate binding to the benzodiazepine/GABA receptor chloride ionophore complex.
A quantitative relationship between the efficacy (i.e. maximum enhancement) of Cl- to increase [3H]flunitrazepam binding and the density of [35S]t-butylbicyclophosphorothionate binding sites was observed in well-washed membrane fragments of rat cerebral cortex previously exposed to phospholipase A2. This relationship (described by the equation y = ABx) was maintained when [3H]flunitrazepam was assayed at Cl- concentrations between 100 and 600 mM, and was not qualitatively altered by the presence of 100 microM pentobarbital. However, under experimental conditions that reduced the ratio of [35S]TBPS binding sites/benzodiazepine receptors, the effects of pentobarbital suggest that the conductance state of benzodiazepine receptor-coupled chloride channels may be the primary determinant of Cl- enhanced [3H]flunitrazepam binding.
D000818:Animals; D001643:Bridged Bicyclo Compounds / Q000378:metabolism*; D019086:Bridged Bicyclo Compounds, Heterocyclic; D001952:Bridged-Ring Compounds / Q000378:metabolism*; D002540:Cerebral Cortex / Q000378:metabolism*; D002712:Chlorides / Q000494:pharmacology*; D005445:Flunitrazepam / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D010741:Phospholipases A / Q000494:pharmacology; D054467:Phospholipases A2; D051381:Rats; D011919:Rats, Inbred Strains; D011963:Receptors, GABA-A / Q000378:metabolism*; D013268:Stimulation, Chemical
D001643:Bridged Bicyclo Compounds; D019086:Bridged Bicyclo Compounds, Heterocyclic; D001952:Bridged-Ring Compounds; D002712:Chlorides; D011963:Receptors, GABA-A; D005445:Flunitrazepam; C037476:tert-butylbicyclophosphorothionate; D010741:Phospholipases A; D054467:Phospholipases A2