The effects of indeloxazine hydrochloride on disturbances of passive avoidance behavior in senescence-accelerated mice (SAM) were observed. The step-through latency of SAM-P/8/Ta (SAM-P/8, senescence-prone substrain) was significantly shorter than that of SAM-R/1/Ta (SAM-R/1, senescence-resistant substrain). The administration of indeloxazine (10-30 mg/kg p.o.) or dihydroergotoxine (1 mg/kg i.p.) for 3 weeks significantly prolonged the step-through latency of SAM-P/8/Ta whereas piracetam (30-300 mg/kg p.o.) did not. These results suggest that indeloxazine has a facilitatory effect on cerebral functions and that it has a broader pharmacological profile in anti-amnesic activities than piracetam.