Theanine has no direct effect on Dopamine. It is the GABA & Glutamate which theanine is converted into that alters Dopamine, and this can infact mean that Dopamine levels are reduced in some areas of the brain. Glutamate and GABA regulate the other neurotransmitter systems.
there seems to be some evidence saying that dopamine is indeed
increased in some regions of the brain.
Yokogoshi H, Kobayashi M, Mochizuki
M, Terashima T. Effect of theanine, rglutamylethylamide,
on brain monoamines
and striatal dopamine release in conscious rats.
Neurochem Res 1998;23:667-673.
And that is the only logical explanation, that tyrosine and theanine lead to increased catecholamine levels way above what could be done with tyrosine alone. That also would explain anxiety when combining both. Tyrosine increases catecholamines, so if your hypothesis were correct, brain levels should return torwards baseline after being reduced by theanine. And that would mean less side effects, more normal function. Only a accumulation effect however can explain why tyrosine, that increases catecholamines, and theanine, which does the same in some areas of the brain combined produce these side effects. This would only work out if both substances would lower catecholamines, which they do not. Also, even though gaba regulates neurotransmitters it does not choose differently which neurotransmitters to reduce, just because it got increased by theanine. Actually, if gaba is increased it should have an inhibitory effect on neurotransmitters, dampening the effect tryosine and with it increased catecholamine levels have, not increasing it. To make it short, I think your hypothesis can not explain the side effects of combining tyrosine and theanine.
Actually, I would say the side effects of combining both were more like LESS inhibitory neurotransmitters in my brain. I once used beta alanine's effect on gaba receptors for anxiety, and it worked just like any other drug that I heard from that uses gaba receptors. I could go very high with beta alanine, because I did not have side effects like other people have on higher dosages. When I came off, I also had this feeling of overstimulation. But tyrosine and theanine are WAY stronger, I never felt so overstimulated, and it was the first time I was fearing to get a seizure. So if any, then inhibitory effects get less not more... And both gaba and glutamate are inhibitory, so again, combining tyrosine with theanine should inhibit the brain, compared to tyrosine alone.
when I think about it that way - maybe ops problems are simply receptor downregulation of gaba, and bacopa monnieri would fix this. Don't know if that would help with glutamate receptor downregulation though, it that would be the case too
actually, I have my own hypothesis now:
1. theanine increased gaba and glutamate, producing a relaxed feeling
2. theanine increased dopamine and serotonin in several areas of the brain. this combination could lead to the alpha wave pattern. stimulated, but "in check"
3. gaba (and glutamate?) receptors get desensitized.
4. dopamine and serotonin are not increased in the frontal lobe, where all the complex thinking stuff happens, but still in other areas of the brain -> now exhibitory forces are stronger, and in areas that may not prove beneficial to us.
upon quitting theanine, dopamine and serotonin should return to baseline, but gaba receptor sensitivity is still present AND gaba is much less then before. hence, side effects from too few inhibitory neurotransmitter action in the brain, until gaba/glutamate neurotransmitters have been upregulated again, and an explanation for op's problem.
so everytime op uses a stimulant, tyrosine, caffeine etc, he increases exhibitory effects in the brain, but the brain has below par inhibitory action, resulting in overstimulation. Gaba is not able to get through the BBB, so it would have no effect at all on the brain, while stimulants would. Picamilon gets through the BBB, but it may be a too low dose, in relation to the downregulation of gaba receptors thats still in place.
So I would stop taking ANY stimulants, NO gaba receptor activating supplements, and try to increase gaba sensitivity. That could work out.
I have yet to find a use for the theanine I have left. damn.
Edited by BioFreak, 13 February 2013 - 01:20 PM.