EFFECTS OF IDEBENONE ON INFORMATION-PROCESSING IN AGED LONG-EVANS RATS

Idebenone oxydecyl)-2,3-dimethoxy-5-methyl-1,4-benzoquinone) is a benz oquinone that has been shown to improve cognitive function in animals subjected to cerebral ischemia and in rats with lesions of the basal f orebrain cholinergic system. Because the cognitive deficits observed i n aged rats have been associated with decreased cerebral blood flow an d basal forebrain cholinergic dysfunction, it was hypothesized that ID E might improve cognition in aged animals. In the present study, the e ffects of idebenone on cognitive function in aged Long-Evans rats were assessed using a battery of tests that evaluated attention, habituati on, and spatial learning. Selective attention was assessed using an ov ershadowing paradigm, where IDE (30 mg/kg, IP) was injected 30 min pri or to compound cue exposure. IDE enhanced the overshadowing effect in aged rats. The Morris water maze was used to assess spatial learning, where IDE (3 mg/kg, IP) was injected daily throughout the course of tr aining. IDE did not improve the impaired performance of aged rats in t he Morris task. Habituation was tested by measuring recovery from gust atory neophobia. IDE (30 mg/kg, IP) was injected 30 min prior to the f irst exposure to the novel taste. IDE normalized habituation rate in a ged rats. It was concluded that IDE improves some forms of acquisition in aged rats, and may do so by decreasing general reactivity to novel stimuli.