Learning more about depression and anti-depressants
The most widely used prescription anti-depressants fall into the category called selective serotonin reuptake inhibitors or SSRIs.
These include fluoxetine (Prozac), paroxetine (Paxil), sertraline (Zoloft), and others.
These medications inhibit the reuptake of serotonin in order to make more available in the brain.
The anti-depressant effect comes from the increased available serotonin.
L-theanine and serotonin research
Theanine is a unique amino acid protein from green tea (Camellia sinensis).
Smaller amounts are also found in black and oolong tea from Camellia sinensis, and some mushrooms.
This amino acid has tested safe for human consumption to date.
No side effects have been attributed to it even at higher doses.
Several theanine serotonin studies have found that theanine ingestion (the same as drinking several cups of green tea) increases available serotonin in the brain, particularly in the striatum, hypothalamus, and hippocampus.
These studies are preliminary.
An animal study shows that theanine will provide anti-depressant effects for behavior under chronic stress.
A 2013 study found it relieved psychosocial stress by modulating activity in the hypothalamus, adrenals, and pituitary.
In addition, there are already positive studies showing improved memory, improved concentration, and improved mood effects.
People who are taking any anti-depressant medication must consult with their physicians before making lifestyle changes as abrupt changes could cause very dangerous side-effects.
Unno K, et al: Theanine intake improves the shortened lifespan, cognitive dysfunction and behavioural depression that are induced by chronic psychosocial stress in mice. Free Radical Research, August 2011 p966-74
Yamada T, et al: Theanine, r-glutamylethylamide, increases neurotransmission concentrations and neurotrophin mRNA levels in the brain during lactation. Life Sciences, September 2007
Nathan PJ, et al: The neuropharmacology of L-theanine(N-ethyl-L-glutamine): a possible neuroprotective and cognitive enhancing agent. Journal of Herbal Pharmacotherapy 2006
Yokogoshi H, et al: Effect of theanine, r-glutamylethylamide, on brain monoamines and striatal dopamine release in conscious rats. Neurochemical Research May 1998
Yokogoshi H, et al: Reduction effect of theanine on blood pressure and brain 5-hydroxyindoles in spontaneously hypertensive rats. Bioscience, Biotechnology, and Biochemistry April 1995
Kimura R and Murata T: Effect of theanine on norepinephrine and serotonin levels in rat brain. Chemical and Pharmaceutical Bulletin, July 1986
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This page last updated by Sharon Jones on January 28, 2013
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