Sedative-
hypnotic drugs commonly used in the elderly may affect functional recovery following cerebrovascular events. Previous research has shown that prolonged exposure to
diazepam can interfere with recovery of function and exaggerate tissue loss after
brain injury. The present study evaluated the effect of
zopiclone, a widely used
hypnotic drug, on functional and histological outcome after cortical photothrombosis in aged rats, which might be particularly vulnerable to brain insults and inhibitory
sedative-
hypnotic drugs. Aged Wistar rats were treated with
zopiclone at a dose of 3 mg/kg (i.p., once a day) beginning 4 days before
ischemia induction and continuing for 23 days. Sensorimotor recovery was assessed by a new ledged beam-walking test and spatial learning by the Morris water-maze. After a 7-day washout period all rats were administered a single dose of
zopiclone (3 mg/kg, i.p.) and retested.
Infarct volumes were measured from
nitroblue tetrazolium-stained sections at the end of the experiment. Beam-walking data showed that ischemic rats treated with
zopiclone were not more impaired than untreated rats. Indeed, they showed fewer faults with the impaired hindlimb than ischemic controls on post-operative day 16. Water-maze performance was not affected by
zopiclone. After the washout period a single dose of
zopiclone did not worsen forelimb or hindlimb function, but seemed to improve performance in the water-maze test. Cortical
infarct volumes were similar in ischemic controls and ischemic rats treated with
zopiclone. In conclusion,
zopiclone was not detrimental and even seemed to improve behavioral outcome without affecting ischemic damage in aged rats subjected to cortical photothrombosis.