• DOI:10.1111/j.1471-4159.1986.tb04511.x
• Corpus ID: 42138610

Enhancement of γ‐Aminobutyric Acid Binding by Quazepam, a Benzodiazepine Derivative with Preferential Affinity for Type I Benzodiazepine Receptors

@article{Corda1986EnhancementO,
  title={Enhancement of $\gamma$‐Aminobutyric Acid Binding by Quazepam, a Benzodiazepine Derivative with Preferential Affinity for Type I Benzodiazepine Receptors},
  author={M. G. Corda and Enrico Sanna and A Concas and Osvaldo Giorgi and Ennio Ongini and Valeria Marina Nurchi and Teresa Pintori and Guido Crisponi and Giovanni Biggio},
  journal={Journal of Neurochemistry},
  year={1986},
  volume={47}
}

• M. Corda, E. Sanna, +6 authors G. Biggio
• Published 1 August 1986
• Biology, Chemistry
• Journal of Neurochemistry

Abstract: We evaluated the effect of the two N‐trifluoroethyl benzodiazepines, quazepam and its 2‐oxo metabolite SCH 15725, which possess preferential affinity for type I benzodiazepine recognition sites, on the binding of [3H]γ‐aminobutyric acid ([3H]GABA) to rat brain membrane preparations. The study also included compounds such as diazepam and N‐desalkyl‐2‐oxoquazepam (SCH 17514), which have equal affinity for the type I and type II receptor subtypes. Binding of [3H]GABA was studied in frozen‐thawed and repeatedly washed cortical membranes incubated in 20 mM KH2PO4 plus 50 mM KCl, pH 7.4, at 4°C in the absence and presence of quazepam or its metabolites. Addition of 10−‐6M quazepam increased by 30% specific [3H]GABA binding; as revealed by Scatchard plot analysis, the effect was due to an increase in the total number of GABA receptors. The effect of quazepam was concentration dependent, and it was shared by its active metabolite SCH 15725. The potency of quazepam and SCH 15725 in enhancing [3H]GABA binding was similar to that of diazepam, whereas CL 218872 and SCH 17514 were less active. Moreover, the [3H]GABA binding‐enhancing effect of quazepam was mediated by an occupancy of benzodiazepine receptors, because it was specifically antagonized by 5 × 10−‐6M Ro15–1788.