The in vivo synaptic plasticity mechanism of EGb 761-induced enhancement of spatial learning and memory in aged rats.
It has not been uniform to date that the Ginkgo biloba extracts enhance cognitive function in aged animals, and the mechanisms of action remain difficult to elucidate. In this study, the Morris water maze task and electrophysiological methods were used to study the effects of repeated daily administration of EGb 761, a standardized extract from G. biloba leaves, on hippocampal-dependent spatial learning and memory and synaptic plasticity of aged rats. The adult subjects perform the Morris water maze task better than aged rats, as a cellular mechanism, the hippocampal long-term potentiation (LTP) elicited from adult animals is robust (139.29+/-2.7%). In addition, the spatial learning and memory of aged rats that had been fed on an EGb 761-supplemented diet (60 mg kg(-1)) for 30 days were significantly better than those of control aged rats. The magnitude of LTP (116.63+/-3.6%) recorded in vivo from the hippocampus CA1 area of aged rats was significantly enhanced by EGb 761 (60 mg kg(-1)). In conclusion, the spatial learning and memory of aged rats is worse than that of young subjects, and EGb 761, acting as a 'cognitive enhancer', has benefit on synaptic plasticity and cognition in aged rats. The present data further confirmed that enhancement of synaptic plasticity of the hippocampus might ameliorate the deficit in spatial learning and memory in aged rats.
Section of Brain and Behavior, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, Yunnan, PR China.
Yongfu
Y
Wang
Lei
L
Wang
Jing
J
Wu
Jingxia
J
Cai
D000375:Aging; D000818:Animals; D004305:Dose-Response Relationship, Drug; D020441:Ginkgo biloba; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology; D017774:Long-Term Potentiation / Q000187:drug effects; D008297:Male; D018782:Maze Learning / Q000187:drug effects*; D008568:Memory / Q000187:drug effects*; D009473:Neuronal Plasticity / Q000187:drug effects*; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013028:Space Perception / Q000187:drug effects; D013997:Time Factors; D014792:Visual Acuity / Q000187:drug effects; D000096983:Ginkgo Extract
D010936:Plant Extracts; C063170:Ginkgo biloba extract; D000096983:Ginkgo Extract