Pharmacological and clinical studies of cyclopyrrolones: zopiclone and suriclone.

Among the non-benzodiazepine compounds which have been found to interact with the "GABA receptor-BZ receptor-chloride channel complex," the very chemically original cyclopyrrolone family has a special place. This has been demonstrated using selected pharmacological, biochemical and clinical data obtained with two cyclopyrrolones, zopiclone and suriclone, which, in addition to their capacity of displacing BZ from their sites, simultaneously possess the main pharmacological properties of BZ and well established therapeutic activities, as hypnotic and anxiolytic, respectively. However, although cyclopyrrolones recognize BZ receptor sites, their mechanism of action might not exactly fit with that of BZ. Indeed, using tritiated zopiclone and suriclone, it has been shown that they could act on sites distinct from those of BZ or could induce receptor conformational changes different from those induced by BZ.