Several new benzodiazepines selectively interact with a benzodiazepine receptor subtype.

The potency of several new benzodiazepines as inhibitors of [3H]flunitrazepam binding was investigated in membranes from rat cerebellum or hippocampus. It was found that quazepam and two of its metabolites have a higher affinity for benzodiazepine receptors in cerebellum than for those in hippocampus, indicating a preferential interaction of these compounds with BZ1-receptors. Other experiments indicated that these compounds have benzodiazepines agonistic properties similar to diazepam or flunitrazepam. Thus for the first time, benzodiazepines have been identified with differentially interact with different benzodiazepine receptors.