The in vivo synaptic plasticity mechanism of EGb 761-induced enhancement of spatial learning and memory in aged rats.
Wang Y, Wang L, Wu J, Cai J.
[1] 1Section of Brain and Behavior, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, Yunnan, PR China [2] 2Graduate School of the Chinese Academy of Sciences, Beijing 100039, PR China.
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.British Journal of Pharmacology advance online publication, 20 March 2006; doi:10.1038/sj.bjp.0706720.
PMID: 16547523 [PubMed - as supplied by publisher]
If we convert the rat dosage into its human equivalent dosage (HED) , a 70 kg human would need to take ~680mg
Learn how to convert/estimate to HED here:
http://www.imminst.o...n equivalent&s=
Another study supporting ginkgo use:
Protective effects of extract of Ginkgo biloba (EGb 761) on nerve cells after spinal cord injury in rats.
Ao Q, Sun XH, Wang AJ, Fu PF, Gong K, Zuo HZ, Gong YD, Zhang XF.
[1] 1State Key Laboratory of Biomembrane and Membrane Biotechnology, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing, China [2] 4Yuquan Hospital, Tsinghua University, Beijing, China.
Study design:An experimental animal model was used to assess spinal cord injury following lateral hemitransection at thoracic spinal cord level.Objective:To determine whether extract of Ginkgo biloba (EGb) could have a neuroprotective effect in spinal cord injury (SCI) in rats.Setting:Department of Biological Sciences and Biotechnology, Tsinghua University, China.Methods:A total of 72 adult rats were divided randomly into three groups: the EGb group, normal saline (NS) group, and sham operation group (sham group). After thoracic spinal cord hemitransection was performed at the level of the 9th thoracic vertebra (T9), rats in the EGb group were given 100 mg/kg EGb 761 daily, while rats in the NS group received NS. The rats in the sham group only underwent laminectomy without spinal cord hemitransection. At various time points after surgery, thoracic spinal cords were sampled and sliced for histochemistry, immunohistochemistry of inducible nitric oxide synthase (iNOS), and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) of apoptotic cells.Results:Myelin staining showed that the area of cavities was small and the demyelinated zones were limited at and around the injury site of the spinal cord in the EGb group, while the area of cavities was large and the demyelinated zones were serious in the NS group. Nissl staining showed that the ratio of bilateral ventral horn neurons (transection side/uninjured side) in the EGb group was higher than that in the NS group (P<0.05). The apoptotic index and the percentage of iNOS-positive cells were lower in the EGb group than in the NS group. Furthermore, the percentage of iNOS-positive cells positively correlated with the apoptotic index (r (2)=0.729, P<0.01) after SCI.Conclusion:This study demonstrated that EGb 761 could inhibit iNOS expression and have neuroprotective effect by preventing nerve cells from apoptosis after SCI in rats.Spinal Cord advance online publication, 17 January 2006; doi:10.1038/sj.sc.3101900.
PMID: 16415923 [PubMed - as supplied by publisher]
and while I'm at it
Stabilization of Mitochondrial Membrane Potential and Improvement of Neuronal Energy Metabolism by Ginkgo Biloba Extract EGb 761.
Eckert A, Keil U, Scherping I, Hauptmann S, Muller WE.
Neurobiology Research Laboratory, Psychiatric University Clinic Basel, CH-4025 Basel, Switzerland. anne.eckert@upkbs.ch.
Ginkgo biloba extract EGb 761 has been used for many years to treat age-related cognitive disorders including Alzheimer's disease. EGb 761 given shortly after initiating mitochondrial damage by sodium nitroprusside (nitric oxide donor) improved the mitochondrial membrane potential of PC12 cells significantly and dose dependently. Under these conditions, EGb 761 also reversed the decrease in ATP production. In addition, similar protection against oxidative damage was found in dissociated brain cells and isolated brain mitochondria after in vitro or in vivo treatment with EGb 761. Moreover, PC12 cells bearing an Alzheimer's disease-related mutation in the amyloid precursor protein, which leads to enhanced beta amyloid production, showed greater benefit from treatment with EGb 761 than did control cells. Taken together, our findings clearly show stabilization and protection of mitochondrial function as a specific and very sensitive property of EGb 761 at therapeutically relevant doses.
PMID: 16387710 [PubMed - in process]
And for those interested, here is the Ginkgo Biloba Monograph
Edited by zoolander, 06 April 2006 - 09:34 AM.
