We know that l-theanine increases DA release in striatum
This suggests that l-theanine may have nutrient partitioning effect in manner analogous to bromo or nicotine (i.e., stimulate the D1 or D2 receptors).
Below are two abstracts on l-theanine. Together they "sort of" support the preceding view. The first abstract is about l-theanine's effect on obese mice. The second abstract is about the increase in dopamine release after l-theanine injection into mice brain.
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Anti-obesity effects of three major components of green tea, catechins, caffeine and theanine, in mice.
Zheng G, Sayama K, Okubo T, Juneja LR, Oguni I.
Department of Applied Biological Chemistry, Faculty of Agriculture, Shizuoka University, 836 Ohya, Shizuoka-shi 422-8529, Japan.
To elucidate the anti-obesity effects of three major components of green tea, catechins, caffeine and theanine, female ICR mice were fed on diets containing 2% green tea powder and diets containing 0.3% catechins, 0.05% caffeine and 0.03% theanine, which correspond, respectively, to their concentrations in a 2% green tea powder diet, singly and in combination for 16 weeks. Body weight and food intake were determined monthly during this period, kidneys, adrenals, liver, spleen, brain, pituitary and intraperitoneal adipose tissues (IPAT) were weighed and lipid levels in the serum and liver were measured at the end of this period. The body weight increase and weight of IPAT were significantly reduced by the diets containing green tea, caffeine, theanine, caffeine + catechins, caffeine + theanine and caffeine + catechins + theanine. Noticeably, the IPAT weight decreased by 76.8% in the caffeine + catechins compared to the control group. Serum concentrations of triglycerides (TG) and non-esterified fatty acids (NEFA) were decreased by green tea, catechins and theanine. Moreover, caffeine + catechins, caffeine + theanine and caffeine + catechins + theanine also decreased NEFA in the serum. The TG level in the liver was significantly reduced by catechins and catechins + theanine in comparison with the control. These results indicated that at least caffeine and theanine were responsible for the suppressive effect of green tea powder (GTP) on body weight increase and fat accumulation. Moreover, it was shown that catechins and caffeine were synergistic in anti-obesity activities.
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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.
Full Version: Nutrient partitioning effect of l-theanine
theanine is definitely interesting.
While I don't have much to add in terms of theanine being a DA agonist, I did think these two other properties might be interesting:
Funny side note:
I'm on a terminal in the library, and I thought I hit the control-c to copy the ref, so I hit control-v in this window topaste, and this came up: Cartographies of Desire: Male-Male Sexuality in Japanese Discourse, 1600-1950. I swear, it's from somone else...or is it?
Anyway, the abstract..theanine is a gluatamate analogue that inhibits the glutamate transporter, which is probably one of the ways it exerts sedative/anxiolytic effects
Toxicol Lett. 2001 Apr 30;121(2):89-96.
Inhibition of glutamate transporter by theanine enhances the therapeutic efficacy of doxorubicin. Sugiyama T, Sadzuka Y, Tanaka K, Sonobe T.
Secondly, while I ought to check out the full text, it appears theanine might have some antagonistic effects on 5-HT:
Biosci Biotechnol Biochem. 1998 Apr;62(4):816-7. Theanine-induced reduction of brain serotonin concentration in rats. Yokogoshi H, Mochizuki M, Saitoh K.
This serotonin reducing effect is similar to other dopaminergic drugs with weight loss action, notably cocaine and nicotine.
While I don't have much to add in terms of theanine being a DA agonist, I did think these two other properties might be interesting:
Funny side note:
I'm on a terminal in the library, and I thought I hit the control-c to copy the ref, so I hit control-v in this window topaste, and this came up: Cartographies of Desire: Male-Male Sexuality in Japanese Discourse, 1600-1950. I swear, it's from somone else...or is it?
Anyway, the abstract..theanine is a gluatamate analogue that inhibits the glutamate transporter, which is probably one of the ways it exerts sedative/anxiolytic effects
Toxicol Lett. 2001 Apr 30;121(2):89-96.
Inhibition of glutamate transporter by theanine enhances the therapeutic efficacy of doxorubicin. Sugiyama T, Sadzuka Y, Tanaka K, Sonobe T.
Secondly, while I ought to check out the full text, it appears theanine might have some antagonistic effects on 5-HT:
Biosci Biotechnol Biochem. 1998 Apr;62(4):816-7. Theanine-induced reduction of brain serotonin concentration in rats. Yokogoshi H, Mochizuki M, Saitoh K.
This serotonin reducing effect is similar to other dopaminergic drugs with weight loss action, notably cocaine and nicotine.
QUOTE(Novick @ Mar 29 2004, 08:04 PM)
This serotonin reducing effect is similar to other dopaminergic drugs with weight loss action, notably cocaine and nicotine.
I am curious, what is the mechanism by which cocaine and nicotine reduce the serotonin?
BTW, is "cartography of desire" the same thing as pornography?
Honestly, I'm not too sure what the exact mechanism is. Definitely something to look into.
From a very simplified point of view, dopaminergic activity says "more, more, more", serotonergic activity says "stop, we're full", so it makes sense that they are somewhat antagonistic to each other. In the literature, it often refers to the DA/5-HT "balance of power." When it gets shifted too much to the DA side (as with cocaine and nicotine), you get addictive, impulsive behavior. Shifted too much to the 5-HT side, you get anergia and ahedonia (which is part of depression).
I'm banking that the answer to your question probably lies in the function of one or more of the DA receptor subtypes.
From a very simplified point of view, dopaminergic activity says "more, more, more", serotonergic activity says "stop, we're full", so it makes sense that they are somewhat antagonistic to each other. In the literature, it often refers to the DA/5-HT "balance of power." When it gets shifted too much to the DA side (as with cocaine and nicotine), you get addictive, impulsive behavior. Shifted too much to the 5-HT side, you get anergia and ahedonia (which is part of depression).
I'm banking that the answer to your question probably lies in the function of one or more of the DA receptor subtypes.
I have always wanted to get my hands on the full text of this one.
Mason R. 200 mg of Zen; L-theanine boosts alpha waves, promotes alert relaxation. Alternative & Complementary Therapies 2001 April; 7:91-95.
Probably a lot of pseudoscience, but it would be interesting to read. Theanine is definitely interesting, and research on it seems to be lacking, especially given that it is an amino acid that many consume on a regular basis.
Mason R. 200 mg of Zen; L-theanine boosts alpha waves, promotes alert relaxation. Alternative & Complementary Therapies 2001 April; 7:91-95.
Probably a lot of pseudoscience, but it would be interesting to read. Theanine is definitely interesting, and research on it seems to be lacking, especially given that it is an amino acid that many consume on a regular basis.
In the past I have written about the effect l-theanine has on sleep, combination of ALCAR.
Its effect on sleep becomes sharply pronounced (in conjunction with ALCAR) as administration dosage is increased. Spook mentioned that this maybe due to glutamate rush (which is caused by ALCAR). As far as glutamate rush goes, if it does exist, I think it is more likely to be caused by l-theanine's. See Novick's reference above.
Its effect on sleep becomes sharply pronounced (in conjunction with ALCAR) as administration dosage is increased. Spook mentioned that this maybe due to glutamate rush (which is caused by ALCAR). As far as glutamate rush goes, if it does exist, I think it is more likely to be caused by l-theanine's. See Novick's reference above.
......
theanine makes you a dumb fvck
There has been some interesting research in the last couple of years since the last post in this thread, especially concerning the effects of L-Theanine on DA neurons and overall brain neurotransmitter levels.
Complicating the seemingly linear antagonist relationship with glutamate as an explanatory factor in producing anxiolytic effects, the authors of the following study conclude that while theanine (structurally similar to GABA) does increase striatial dopamine release, the effect on glutamate is distinct from known blockers of the excitatory amino acid, and suggests the possible inhibitory role of glycine in demonstrating the anxiolytic mechanism of action -
A more recent study from Life Sciences examines the effect of theanine on neurotransmitter and neurotrophin levels in the developing rat brain, and the results suggest a positive modulating role in the early development and formation of the CNS.
The third and most recent study illuminates, in some respects, the connection between increased dopamine release and indirect inhibitory effect at excitatory amino acid transmitter sites (e.g., glutamate). The authors found that increases in DA release were dependent primarily on the glycine receptor site, and suggests more specifically that AMPA receptors are inhibited at the studied concentrations as a subset of the broader family of glutaminergic receptors.
L-Theanine is a very novel compound whose mechanism of action seems to be implicated at the amino acid transmitter level, with a cascade of unique effects on catecholamines and inhibitory neurotransmission.
Complicating the seemingly linear antagonist relationship with glutamate as an explanatory factor in producing anxiolytic effects, the authors of the following study conclude that while theanine (structurally similar to GABA) does increase striatial dopamine release, the effect on glutamate is distinct from known blockers of the excitatory amino acid, and suggests the possible inhibitory role of glycine in demonstrating the anxiolytic mechanism of action -
QUOTE
Nutr Neurosci. 2005 Aug;8(4):219-26.
Effects of theanine, r-glutamylethylamide, on neurotransmitter release and its relationship with glutamic acid neurotransmission.
Yamada T, Terashima T, Okubo T, Juneja LR, Yokogoshi H.
Laboratory of Nutritional Biochemistry, Ministry of Education, Culture, Sports, Science and Technology of Japan, University of Shizuoka. takashic64@hotmail.com
t Theanine, r-glutamylethylamide, is one of the major amino acid components in green tea and many researchers have compared theanine's effects with glutamic acid because the chemical structure is similar. In the previous study, we demonstrated that theanine can pass brain-blood barrier and may play as an agonist or an antagonist of some receptors. In this study, we investigated the effects of theanine on neurotransmitter release in the rat brain striatum by in vivo brain microdialysis and examined whether theanine affected glutamate transporters by comparing it with a glutamate transporter blocker, L-trans-Pyrrolidine-2,4-dicarboxylic acid (L-trans-2,4-PDC). Because we investigated whether the effects of theanine is similar to L-trans-2,4-PDC on the brain neurotransmission, we measured dopamine release and some amino acids release which are known as excitatory or inhibitory neurotransmitters from neurons by theanine or L-trans-2,4-PDC perfusion into the rat brain striatum. L-trans-2,4-PDC or theanine perfusion into the brain striatum caused dopamine release from dopaminergic neurons. In addition, L-trans-2,4-PDC perfusion increased glutamic acid, aspartic acid and, whereas theanine perfusion prevented aspartic acid release and increased glycine release. These results suggested that the mechanism of dopamine release caused by theanine is different from glutamate transporter blockers or glutamic acid. Further, L-trans-2,4-PDC cause excitatory neurotransmission, whereas theanine may inhibit excitatory neurotransmission and cause inhibitory neurotransmission via glycine receptors.
PMID: 16493792.
Effects of theanine, r-glutamylethylamide, on neurotransmitter release and its relationship with glutamic acid neurotransmission.
Yamada T, Terashima T, Okubo T, Juneja LR, Yokogoshi H.
Laboratory of Nutritional Biochemistry, Ministry of Education, Culture, Sports, Science and Technology of Japan, University of Shizuoka. takashic64@hotmail.com
t Theanine, r-glutamylethylamide, is one of the major amino acid components in green tea and many researchers have compared theanine's effects with glutamic acid because the chemical structure is similar. In the previous study, we demonstrated that theanine can pass brain-blood barrier and may play as an agonist or an antagonist of some receptors. In this study, we investigated the effects of theanine on neurotransmitter release in the rat brain striatum by in vivo brain microdialysis and examined whether theanine affected glutamate transporters by comparing it with a glutamate transporter blocker, L-trans-Pyrrolidine-2,4-dicarboxylic acid (L-trans-2,4-PDC). Because we investigated whether the effects of theanine is similar to L-trans-2,4-PDC on the brain neurotransmission, we measured dopamine release and some amino acids release which are known as excitatory or inhibitory neurotransmitters from neurons by theanine or L-trans-2,4-PDC perfusion into the rat brain striatum. L-trans-2,4-PDC or theanine perfusion into the brain striatum caused dopamine release from dopaminergic neurons. In addition, L-trans-2,4-PDC perfusion increased glutamic acid, aspartic acid and, whereas theanine perfusion prevented aspartic acid release and increased glycine release. These results suggested that the mechanism of dopamine release caused by theanine is different from glutamate transporter blockers or glutamic acid. Further, L-trans-2,4-PDC cause excitatory neurotransmission, whereas theanine may inhibit excitatory neurotransmission and cause inhibitory neurotransmission via glycine receptors.
PMID: 16493792.
A more recent study from Life Sciences examines the effect of theanine on neurotransmitter and neurotrophin levels in the developing rat brain, and the results suggest a positive modulating role in the early development and formation of the CNS.
QUOTE
Life Sci. 2007 Sep 29;81(16):1247-55. Epub 2007 Aug 31.
Theanine, r-glutamylethylamide, increases neurotransmission concentrations and neurotrophin mRNA levels in the brain during lactation.
Yamada T, Terashima T, Wada K, Ueda S, Ito M, Okubo T, Juneja LR, Yokogoshi H.
Laboratory of Nutritional Biochemistry, COE Program in the 21st Century and CITY AREA, Ministry of Education, Culture, Sports, Science and Technology of Japan, University of Shizuoka, 52-1 Yada, Shizuoka, Japan.
Theanine (r-glutamylethylamide) is one of the major amino acid components in green tea. Recent studies suggest that theanine affects neurotransmission, especially inhibitory neurotransmission. In this study, we investigated whether theanine affects brain development in infant rats, because inhibitory neurotransmission is required for mature brain function. Mother rats were fed theanine ad libitum after confinement. The body weight gain rate of infants was not different from control infants. We detected theanine in the infant serum and measured neurotransmitter concentration and nerve growth factor (NGF) mRNA level in the infant rat brain. Some neurotransmitters, including dopamine, serotonin, glycine and GABA concentration, increased in the infant brain and NGF mRNA level increased in the cerebral cortex and hippocampus. However, these differences were lost by the end of nerve maturity. These results suggest that theanine enhanced synthesis of nerve growth factor and neurotransmitters during a nerve maturing period and promoted central nerve system maturation (CNS). Thus, theanine accelerated maturation. In conclusion, theanine may assist in healthy brain function development.
PMID: 17904164.
Theanine, r-glutamylethylamide, increases neurotransmission concentrations and neurotrophin mRNA levels in the brain during lactation.
Yamada T, Terashima T, Wada K, Ueda S, Ito M, Okubo T, Juneja LR, Yokogoshi H.
Laboratory of Nutritional Biochemistry, COE Program in the 21st Century and CITY AREA, Ministry of Education, Culture, Sports, Science and Technology of Japan, University of Shizuoka, 52-1 Yada, Shizuoka, Japan.
Theanine (r-glutamylethylamide) is one of the major amino acid components in green tea. Recent studies suggest that theanine affects neurotransmission, especially inhibitory neurotransmission. In this study, we investigated whether theanine affects brain development in infant rats, because inhibitory neurotransmission is required for mature brain function. Mother rats were fed theanine ad libitum after confinement. The body weight gain rate of infants was not different from control infants. We detected theanine in the infant serum and measured neurotransmitter concentration and nerve growth factor (NGF) mRNA level in the infant rat brain. Some neurotransmitters, including dopamine, serotonin, glycine and GABA concentration, increased in the infant brain and NGF mRNA level increased in the cerebral cortex and hippocampus. However, these differences were lost by the end of nerve maturity. These results suggest that theanine enhanced synthesis of nerve growth factor and neurotransmitters during a nerve maturing period and promoted central nerve system maturation (CNS). Thus, theanine accelerated maturation. In conclusion, theanine may assist in healthy brain function development.
PMID: 17904164.
The third and most recent study illuminates, in some respects, the connection between increased dopamine release and indirect inhibitory effect at excitatory amino acid transmitter sites (e.g., glutamate). The authors found that increases in DA release were dependent primarily on the glycine receptor site, and suggests more specifically that AMPA receptors are inhibited at the studied concentrations as a subset of the broader family of glutaminergic receptors.
QUOTE
Amino Acids. 2008 Jan 15 [Epub ahead of print]
Theanine, gamma-glutamylethylamide, a unique amino acid in tea leaves, modulates neurotransmitter concentrations in the brain striatum interstitium in conscious rats.
Yamada T, Terashima T, Kawano S, Furuno R, Okubo T, Juneja LR, Yokogoshi H.
Laboratory of Nutritional Biochemistry, COE Program in the 21st Century and Cooperation of Innovative Technology and Advanced Research in Evolutional Area (CITY AREA), Ministry of Education, Culture, Sports, Science and Technology of Japan, University of Shizuoka, Shizuoka, Japan.
Theanine (gamma-glutamylethylamide) is one of the major amino acid components in green tea and can pass through the blood-brain barrier. Recent studies suggest that theanine affects the mammalian central nervous system; however, the detailed mechanism remains unclear. In this study, we demonstrated the effect of theanine on neurotransmission in the brain striatum by in vivo brain microdialysis. Theanine injection into the rat brain striatum did not increase the concentration of excitatory neurotransmitters in the perfusate. On the other hand, theanine injection increased the concentration of glycine in the perfusate. Because it has been reported that theanine promotes dopamine release in the rat striatum, we investigated the glycine and dopamine concentrations in the perfusate. Co-injection of glycine receptor antagonist, strychnine, reduced theanine-induced changes in dopamine. Moreover, AMPA receptor antagonist, which regulates glycine and GABA release from glia cells, inhibited these effects of theanine and this result was in agreement with the known inhibitory effect of theanine at AMPA receptors.
PMID: 18196445.
Theanine, gamma-glutamylethylamide, a unique amino acid in tea leaves, modulates neurotransmitter concentrations in the brain striatum interstitium in conscious rats.
Yamada T, Terashima T, Kawano S, Furuno R, Okubo T, Juneja LR, Yokogoshi H.
Laboratory of Nutritional Biochemistry, COE Program in the 21st Century and Cooperation of Innovative Technology and Advanced Research in Evolutional Area (CITY AREA), Ministry of Education, Culture, Sports, Science and Technology of Japan, University of Shizuoka, Shizuoka, Japan.
Theanine (gamma-glutamylethylamide) is one of the major amino acid components in green tea and can pass through the blood-brain barrier. Recent studies suggest that theanine affects the mammalian central nervous system; however, the detailed mechanism remains unclear. In this study, we demonstrated the effect of theanine on neurotransmission in the brain striatum by in vivo brain microdialysis. Theanine injection into the rat brain striatum did not increase the concentration of excitatory neurotransmitters in the perfusate. On the other hand, theanine injection increased the concentration of glycine in the perfusate. Because it has been reported that theanine promotes dopamine release in the rat striatum, we investigated the glycine and dopamine concentrations in the perfusate. Co-injection of glycine receptor antagonist, strychnine, reduced theanine-induced changes in dopamine. Moreover, AMPA receptor antagonist, which regulates glycine and GABA release from glia cells, inhibited these effects of theanine and this result was in agreement with the known inhibitory effect of theanine at AMPA receptors.
PMID: 18196445.
L-Theanine is a very novel compound whose mechanism of action seems to be implicated at the amino acid transmitter level, with a cascade of unique effects on catecholamines and inhibitory neurotransmission.
any idea of which dopamine subtype we're talking about here... uh.. Dopamine?
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