title: Suriclone: a new cyclopyrrolone derivative recognizing receptors labeled by benzodiazepines in rat hippocampus and cerebellum.
abstract: Suriclone (RP 31,264), like zopiclone (RP 27,267), belongs to the family of cyclopyrrolones and is chemically entirely different from the benzodiazepines (BZDs). However, it possesses a pharmacological profile close to that of the BZDs and proved to be useful in therapeutics as an anxiolytic agent. In the present paper it is shown that suriclone possesses a high affinity for flunitrazepam binding sites and that tritiated suriclone binds specifically with high affinity in rat hippocampus (KD = 0.44 +/- 0.03 nM) and rat cerebellum (KD = 0.53 +/- 0.12 nM). Further, suriclone binding sites are recognized by BZDs or zopiclone, similarly in the two regions. The affinities of four BZD derivatives--nitrazepam, flunitrazepam, diazepam, and chlordiazepoxide--are similar for suriclone and flunitrazepam binding sites. Suriclone binding sites are, like flunitrazepam sites, protected from thermal inactivation by gamma-aminobutyric acid (GABA) (10 microM), but only flunitrazepam binding is enhanced by GABA. It could be postulated from this that suriclone interacts with a subpopulation of receptors that might be modulated differently from flunitrazepam binding sites. Our results indicate that suriclone could be a new probe for investigating the so-called BZD receptors.
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D002531:Cerebellum / Q000378:metabolism*; D002540:Cerebral Cortex / Q000378:metabolism; D005445:Flunitrazepam / Q000378:metabolism; D006624:Hippocampus / Q000378:metabolism*; D006358:Hot Temperature; D007700:Kinetics; D008297:Male; D009287:Naphthyridines; D010879:Piperazines / Q000378:metabolism*; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011963:Receptors, GABA-A; D013457:Sulfur Compounds; D013997:Time Factors; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
chemical_list: D009287:Naphthyridines; D010879:Piperazines; D011956:Receptors, Cell Surface; D011963:Receptors, GABA-A; D013457:Sulfur Compounds; D005680:gamma-Aminobutyric Acid; D005445:Flunitrazepam; C037283:suriclone