Cyclopyrrolones, unlike some benzodiazepines, do not induce physical dependence in mice

In a model of physical dependence in mice, treatment with cyclopyrrolones such as zopiclone and suriclone (from 4 to 400 mg/kg/day), did not modify the sensitivity of the gamma-aminobutyric acid (GABA) receptor complex to the partial inverse agonist FG 7142 following their withdrawal, whereas sensitivity changes were observed after treatment and withdrawal from some benzodiazepines (e.g. lorazepam, diazepam, flunitrazepam and triazolam). These data suggest that, in contrast to some benzodiazepines, zopiclone and suriclone may not produce physical dependence.