Comparison of the effects of bifemelane hydrochloride and indeloxazine hydrochloride on scopolamine hydrobromide-induced impairment in radial maze performance.

The antiamnesic effects of bifemelane hydrochloride (bifemelane) and indeloxazine hydrochloride (indeloxazine) on radial maze performance in rats were assessed. This performance was dependent on working memory and spatial memory, without aversive electric stimuli. When administered alone, neither bifemelane nor indeloxazine had an effect on the task performance of normal rats. However, impairment of the performance of rats induced by scopolamine hydrobromide (scopolamine) injection was dose-dependently reduced by oral treatment with bifemelane. On the other hand, indeloxazine, which was reported to enhance the learning behavior in a passive avoidance test, did not improve the radial maze task performance of scopolamine-treated rats. It has been shown that dysfunction of the cholinergic neuronal system plays an important role in memory loss and that bifemelane induces recovery of reduced cerebral cholinergic neuronal activity associated with brain ischemia or aging. In accordance with these previous findings, our results suggest that bifemelane is useful in the treatment of memory loss and cognitive dysfunction in patients with dementia and cerebrovascular disease.