Effects of Ginkgo biloba extract 761 on learning and memory in chronic alcoholic rats

Objective To investigate the effects of extracts of Ginkgo biloba leaves ( EGb761 ) on learning,memory and the hippocampal long-term potentiation (LTP) in chronic alcoholic rats.Methods 72 SD rats were randomly divided into control group,chronic alcoholism model group,low-dose EGb761 (100 mg/kg) and high-dose EGb761 (200 mg/kg) groups on average.55％ alcohol was given ( 10 ml/kg) by gavages once every day for 6 weeks to create the model of chronic alcoholism.In low-dose and high-dose EGb761 groups,EGb761 was used for gastric infusion 30 minutes before model.The control group and the model group were infused with the same volume of distilled water.Morris water maze (MWM) was used to study the spatial learning and memory in rats.Electrophysiological methods were used to observe the changes of LTP through the comparison of field excitatory postsynaptic potential (fEPSP) slope in hippocampal CA3 region before and after high frequency stimulation (HFS).Results ( 1 ) The escape latency (EL) of model group ( (93.31 ± 14.21 ) s) was longer than that of the control group( (35.28 ±6.51 )s).The mean slope of fEPSP (relative to baseline) after HFS in model group was (96.91 ±7.65) ％,in control group was ( 177.22 ± 10.12) ％ ; Compared with control group,the ability of learning and memory as well as LTP obviously descended in model group.(2) Compared with model group,EGb761(100,200 mg/kg) could shorten the EL.The slope of fEPSP after HFS in either low-dose (( 126.16 ± 5.84)％ )or high-dose (141.31 ± 5.75)％ EGb761 groups was enhanced significantly compared with the model group (96.91 ± 7.65 ) ％,P =0.034,P =0.009 ).Conclusion EGb761 can significantly improve the alcohol-induced memory impairment by means of accelerating the recovery of the pathological synaptic plasticity. Key words: Ginkgo biloba extract;  Long-term potentiation;  Learning and memory;  Alcohol