ABSTRACT
The development of radioligand binding assays proved invaluable for later studies of structure-activity relationships at the benzodiazepine recognition site. The methylene group at the 3-position of a 1,4-benzodiazepine ring is known to be either above or below the plane of the fused benzene ring, imparting conformational chirality to the molecule. The 1,2-annelation of triazolo- or imidazorings to classical 1,4-benzodiazepines generally results in an increase in affinity only for those compounds with a relatively low affinity in the classical series; little increase in affinity is found for the high affinity 1,4-benzodiazepines. Abecarnil has a high affinity for the benzodiazepine receptor and possesses anxiolytic and anticonvulsant properties; it is more potent than diazepam in most rodent tests of anxiolytic activity and in reducing locomotor activity in mice and rats. The pyrazoloquinolinones, CGS 8216, CGS 9895 and CGS 9896 all exhibit high affinity for the benzodiazepine recognition site in vitro.
