Abstract
Whether or not zopiclone, a new sleep-inducing drug, exerted a similar effect to that of benzodiazepines was examined. The drug inhibited crossed extensor reflexes in chicks and augmented the dorsal root-dorsal root reflexes in rats without affecting the mono- and polysynaptic reflexes. The site of its action was considered to be located in the spinal cord since the effect on the dorsal root reflex was observed also in the spinal rats. Zopiclone selectively reduced the phasic responses of anemic decerebrate rigidity like benzodiazepines in rats. Despite the structural difference from the benzodiazepines, zopiclone dose-dependently inhibited [3H]flunitrazepam binding in rat brain membranes, although the potency was weaker. These results suggested that zopiclone exerts CNS actions via benzodiazepine receptors.
