3 replies to this topic

[bliindsniper]

This is a better place to post this than the town hall.

 

Hey everyone, I have been reading some studies on dopamine and ginkgo biloba and i have a question. I think its common knowledge that substances which increase dopamine in the brain tend to downregulate dopamine receptors. However, ginkgo biloba seems to not only increase dopamine in the brain but also (after 15 days of being fed to rats) it almost doubles dopamine receptor density. does anyone have an explanation for this?

 

Heres a link to the study http://www.ncbi.nlm....pubmed/21640798

[Metagene]

Interesting but if my math is right the human equivalent doses are kinda high. (567mg for the study above)

The Ginkgo biloba extract EGb 761® and its main constituent flavonoids and ginkgolides increase extracellular dopamine levels in the rat prefrontal cortex.

KEY RESULTS: A single oral dose of EGb 761 (100 mg.kg(-1)) had no effect on monoamine levels. However, following chronic (100 mg.kg(-1)/14 days/once daily) treatment, the same dose significantly increased extracellular dopamine and noradrenaline levels, while 5-HT levels were unaffected. Chronic treatment with EGb 761 showed dose-dependent increases in frontocortical dopamine levels and, to a lesser extent, in the striatum. The extracellular levels of HVA and DOPAC were not affected by either acute or repeated doses. Treatment with the main constituents of EGb 761 revealed that the increase in dopamine levels was mostly caused by the flavonol glycosides and ginkgolide fractions, whereas bilobalide treatment was without effect.

http://www.ncbi.nlm....2784425/related
http://www.ncbi.nlm....75&from=egb 761

Ginkgo biloba extract (EGb 761) modulates the expression of dopamine-related genes in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinsonism in mice.

Male C57BL/6J mice were injected with MPTP (30 mg/kg, i.p.) for 5 days and later with EGb 761 (40 mg/kg, i.p.) daily for 18 days. The expression of selected genes was evaluated in the striatum and midbrain by quantitative PCR. The genes for tyrosine hydroxylase (Th), vesicular monoamine transporter 2 (Vmat2), dopamine transporter (Dat), dopamine D2 receptor (Da-d2r), and transcription factors (Pitx3 and Nurr1) related to dopamine neurotransmission were selected for the analysis. EGb 761 administration to MPTP-treated mice protected Th (41%), Vmat2 (15%), Dat (102%), Da-d2r (46%), Pitx3 (63%), and Nurr1 (148%) mRNA levels in the midbrain, all of which were up-regulated.

http://www.ncbi.nlm....1 ginkgo biloba

[kimrick]

Ginkgo for dopamine receptor rehab/neurogenesis? TYVM for that...

 

How about this dopamine link:

 

http://www.naturalhe...and-motivation/

 

I don't think tyrosine downregulates dopamine receptors (density)... but this is a smoky area at best.

[OneScrewLoose]

The dose was 50mg/kg in rats, which translates to 8mg/kg in humans. So if you weigh 70kg, that's 560mg per day of a very, very expensive extract of Ginkgo:

http://www.amazon.co...eywords=egb 761

And that's to say the study is valid. But the truth is, one must be very skeptical of studies out of China that promote traditional herbal use, and must comb through them extraordinarily carefully, which I haven't done for this study yet. There is a huge cultural investment on the part of the Chinese Communist Party to boost at least some of their traditional medicine, for nationalistic purposes. That's not to say that none of it works, but that's not what the CCP is interested in (efficacy), they're interested in national pride.

It would be like a drug company ran it's own study to prove the efficacy of a pharmaceutical instead of going through FDA procedures.

But even if it's 100% true, this comes out to about $40 per week.