Posted by Mistermindmasta on December 10, 2004, at 19:59:10
In reply to Re: I was hoping someone would have an answer to this » Mistermindmasta, posted by Larry Hoover on December 10, 2004, at 10:46:23
> > > Here's a link:
> > >
> > > http://www.itmonline.org/arts/theanine.htm
> > >
> > >
> > > "Increase of dopamine levels and changes of serotonin levels by l-theanine have been observed"
> > >
> > > One study: Yokogoshi H, Mochizuki M, and Saitoh K, Theanine-induced reduction of brain serotonin concentration in rats, Bioscience, Biotechnology, and Biochemistry 1998; 62(4): 816-817
> > >
> > >
> >
> > This study is somewhat informative, but it's just as important to know WHERE it affects these neurotransmitters. Serotonin can have stimulatory or inhibitory effects.
> >
> > That being said, I generally associate increased dopamine with more motivation, but my experiences with L theanine are that it doesnt increase motivation, so maybe it increases dopamine in the nigrostriatal tract, since it seems to make me feel more relaxed. Just guessing here. I were to define L theanine's neurotransmitter effects based on how
> > it subjectively feels, i'd say it increases GABA and lowers serotonin (i guess that agrees with the article), since I tend to feel a bit of dysphoria from it. Things are less exciting under the influence of theanine, which i find to be too unacceptable to use on a daily basis, but it certainly does make me more calm and can allow some aspects of my cognition to function better.
>
> Seems like you know you brain very well. :-) You're right on the money, focussing on the striatal tissues.
>
> Neurochem Res. 1998 May;23(5):667-73.
>
> Effect of theanine, r-glutamylethylamide, on brain monoamines and striatal dopamine release in conscious rats.
>
> Yokogoshi H, Kobayashi M, Mochizuki M, Terashima T.
>
> School of Food and Nutritional Sciences, The University of Shizuoka, Yada, Shizuoka, Japan. yokogosi@fns1.u-shizuoka-ken.ac.jp
>
> Theanine, r-glutamylethylamide, is one of the major components of amino acids in Japanese green tea. Effect of theanine on brain amino acids and monoamines, and the striatal release of dopamine (DA) was investigated. Determination of amino acids in the brain after the intragastric administration of theanine showed that theanine was incorporated into brain through blood-brain barrier via leucine-preferring transport system. The concentrations of norepinephrine, 3,4-dihydroxyphenylacetic acid (DOPAC) and 5-hydroxyindole acetic acid (5HIAA) in the brain regions were unaffected by the theanine administration except in striatum. Theanine administration caused significant increases in serotonin and/or DA concentrations in the brain, especially in striatum, hypothalamus and hippocampus. Direct administration of theanine into brain striatum by microinjection caused a significant increase of DA release in a dose-dependent manner. Microdialysis of brain with calcium-free Ringer buffer attenuated the theanine-induced DA release. Pretreatment with the Ringer buffer containing an antagonist of non-NMDA (N-methyl-D-aspartate) glutamate receptor, MK-801, for 1 hr did not change the significant increase of DA release induced by theanine. However, in the case of pretreatment with AP-5, (+/-)-2-amino-5-phosphonopentanoic acid; antagonist of NMDA glutamate receptor, the theanine-induced DA release from striatum was significantly inhibited. These results suggest that theanine might affect the metabolism and/or the release of some neurotransmitters in the brain, such as DA.
>
>
> Biosci Biotechnol Biochem. 1998 Apr;62(4):816-7.
>
> Theanine-induced reduction of brain serotonin concentration in rats.
>
> Yokogoshi H, Mochizuki M, Saitoh K.
>
> Laboratory of Nutritional Biochemistry, School of Food and Nutritional Sciences, University of Shizuoka, Japan. yokogosi@fnsl.u-shizuoka-ken.ac.jp
>
> Following the administration of theanine, the brain tryptophan content significantly increased or tended to increase, but the contents of serotonin and 5-hydroxyindole acetic acid (5HIAA) decreased. The use of inhibitors of serotonin metabolism enable us to speculate that theanine reduced serotonin synthesis and also increased serotonin degradation in the brain.
>
>
> Lar
>Good studies. So the first study showed that the DA release in the striatum is mediated by some sort of increased NMDA functioning. What kind of long term effects might high dose theanine suggest? Neurotoxicity from too much NMDA activity? It would be interesting to shed light on that.
I actually thought I remembered reading some articles where theanine was an NMDA antagonist, which would make it neuroprotective. I don't understand which is correct. I'll have to try and locate that article or study.
But yeah, I have to admit, when I take like 400mg theanine and just lay down, I feel VERY VERY relaxed, and this state of relaxation is enjoyable. But I can't say that it's a true antidepressant feel. They (supplement companies) certainly do try and make theanine seem like it can do way more than it actually does in most people.
poster:Mistermindmasta
thread:421291
URL: http://www.dr-bob.org/babble/alter/20041123/msgs/427444.html