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| ==Pharmacology== | | ==Pharmacology== |
| [[File:Withanolide_series.png|400px|thumb|Chemical structure of Withanolides found in Ashwagandha]] | | [[File:Withanolide_series.png|400px|thumb|Chemical structure of Withanolides found in Ashwagandha]] |
| Theanine is structurally similar to the excitatory [[neurotransmitter]] [[glutamate]], and in accordance, binds to glutamate [[receptor]]s, though with much lower affinity in comparison. Specifically, it binds to ionotropic glutamate receptors including the [[AMPA]] and [[kainate]] receptors and, to a lesser extent, the [[NMDA]] receptor.<ref>The neuropharmacology of L-theanine(N-ethyl-L-glutamine): a possible neuroprotective and cognitive enhancing agent (PubMed.gov / NCBI) | https://www.ncbi.nlm.nih.gov/pubmed/17182482</ref><ref>Inhibition by theanine of binding of [3H]AMPA, [3H]kainate, and [3H]MDL 105,519 to glutamate receptors (PubMed.gov / NCBI) | https://www.ncbi.nlm.nih.gov/pubmed/12596867</ref><ref>Neuroprotective effects of theanine and its preventive effects on cognitive dysfunction (PubMed.gov / NCBI) | https://www.ncbi.nlm.nih.gov/pubmed/21477654</ref><ref>Neuroprotective effects of the green tea components theanine and catechins (PubMed.gov / NCBI) | https://www.ncbi.nlm.nih.gov/pubmed/12499631</ref> It acts as an [[antagonist]] of the former two sites<ref>Neuroprotective effects of the green tea components theanine and catechins (PubMed.gov / NCBI) | https://www.ncbi.nlm.nih.gov/pubmed/12499631</ref> and as an [[agonist]] of the latter site.<ref>Behavioral and molecular evidence for psychotropic effects in L-theanine (PubMed.gov / NCBI) | https://www.ncbi.nlm.nih.gov/pubmed/21861094</ref> In addition, it inhibits glutamine transporters and glutamate transporters, and thus acts as [[reuptake inhibitor]] of glutamine and glutamate.<ref>Neuroprotective effects of the green tea components theanine and catechins (PubMed.gov / NCBI) | https://www.ncbi.nlm.nih.gov/pubmed/12499631</ref><ref>Inhibition of glutamate transporter by theanine enhances the therapeutic efficacy of doxorubicin (PubMed.gov / NCBI) | https://www.ncbi.nlm.nih.gov/pubmed/11325559</ref><ref>Theanine and glutamate transporter inhibitors enhance the antitumor efficacy of chemotherapeutic agents (PubMed.gov / NCBI) | https://www.ncbi.nlm.nih.gov/pubmed/14643924</ref>
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| Theanine increases [[dopamine]], [[GABA]], and [[glycine]] levels in various areas of the brain.<ref>The neuropharmacology of L-theanine(N-ethyl-L-glutamine): a possible neuroprotective and cognitive enhancing agent (PubMed.gov / NCBI) | https://www.ncbi.nlm.nih.gov/pubmed/17182482</ref><ref>Behavioral and molecular evidence for psychotropic effects in L-theanine (PubMed.gov / NCBI) | https://www.ncbi.nlm.nih.gov/pubmed/21861094</ref><ref>Theanine, r-glutamylethylamide, increases neurotransmission concentrations and neurotrophin mRNA levels in the brain during lactation (PubMed.gov / NCBI) | https://www.ncbi.nlm.nih.gov/pubmed/17904164</ref><ref>Effect of theanine, r-glutamylethylamide, on brain monoamines and striatal dopamine release in conscious rats (PubMed.gov / NCBI) | https://www.ncbi.nlm.nih.gov/pubmed/9566605</ref> It also effects [[serotonin]] in a manner which is still a matter of debate in the scientific community, with separate studies showing increases and decreases in brain serotonin levels using similar experimental protocols.<ref>Effect of theanine, r-glutamylethylamide, on brain monoamines and striatal dopamine release in conscious rats (PubMed.gov / NCBI) | https://www.ncbi.nlm.nih.gov/pubmed/9566605</ref><ref>Theanine-induced reduction of brain serotonin concentration in rats (PubMed.gov / NCBI) | https://www.ncbi.nlm.nih.gov/pubmed/9614715</ref>
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| These various changes in neurotransmitter levels contribute to the calming and nootropic properties of theanine.
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| ==Subjective effects== | | ==Subjective effects== |
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| ==Toxicity and harm potential== | | ==Toxicity and harm potential== |
| Theanine is non-addictive, is not known to cause brain damage, and has an [[Toxicity::extremely low toxicity]] relative to dose. Similar to many other [[nootropics]] drugs, there are relatively few physical side effects associated with acute theanine exposure. Various studies have shown that in reasonable doses in a careful context, it presents no negative cognitive, psychiatric or toxic physical consequences of any sort.
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| It is strongly recommended that one use [[responsible drug use|harm reduction practices]] when using this drug. | | It is strongly recommended that one use [[responsible drug use|harm reduction practices]] when using this drug. |
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| ===Tolerance and addiction potential=== | | ===Tolerance and addiction potential=== |
| Theanine is [[Addiction potential::not habit-forming]] and the desire to use it can actually decrease with use. It is most often self-regulating.
| | Ashwaghanda is [[Addiction potential::not habit-forming]]. |
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| Tolerance to the effects of theanine are built [[Time to full tolerance::after prolonged and repeated usage]]. After that, it takes about [[Time to half tolerance::7 days]] for the tolerance to be reduced to half and [[Time to zero tolerance::14 days]] to be back at baseline (in the absence of further consumption). Theanine presents cross-tolerance with [[Cross-tolerance::no other known compounds]], meaning that after the consumption of theanine all other psychoactive compounds will not have a reduced effect.
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| ==Legal issues== | | ==Legal issues== |
| {{LegalStub}} | | {{LegalStub}} |
| Theanine is unscheduled across the world and is not known to be specifically illegal within any country.
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| *'''United Kingdom''' - It is illegal to produce, supply, or import this drug under the Psychoactive Substance Act, which came into effect on May 26th, 2016.<ref>Psychoactive Substances Act 2016 (Legislation.gov.uk) | http://www.legislation.gov.uk/ukpga/2016/2/contents/enacted</ref>
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| ==See also== | | ==See also== |
| *[[Nootropic]] | | *[[Nootropic]] |
| *[[Caffeine]]
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| *[[Glutamate]]
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| ==External links== | | ==External links== |
