EFFECTS OF GINKGO-BILOBA EXTRACT ON IMPAIRMENT OF LEARNING INDUCED BYCEREBRAL-ISCHEMIA IN MICE

The effect of Ginkgo biloba extract (GbE) on cerebral ischemia induced by 10-min bilateral occlusion of the carotid arteries in mice was stu died. Severe impairment of memory was apparent when the passive avoida nce test was carried out 48 hr after bilaterally induced ischemia. Whe n GbE at doses of 50 and 100 mg/kg was given p.o. 1 hr before the 10-m in occlusion, there was a significant improvement in memory. The i.p. injection of ifenprodil (30 mg/kg) also showed improvement on learning tasks. The p.o. administration of flavonoid, a fraction isolated from GbE, showed high step-through latency on scopolamine-induced amnesia. All these findings indicate that GbE is beneficial for clinical use i n amnesia accompanied with cerebral vascular disease.