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1. Néhány referencia a Tyrosin hatásaihoz:
   McLean, 2004 Human:double-blind,placebo-controlledclinical study Healthy subjects received a tyrosine-deficient or tyrosine-sufficient diet. Subjects in the tyrosine-deficient group became less content, more apathetic and had a sad latency bias (depression).
   Mouret, 1988 Human Patients with polysommographic and clinical signs of dopamine-dependent depression received 3,200 mg of tyrosine per day. Tyrosine improved mood in dopamine-dependent depression patients within one day of commencing tyrosine therapy.
   Gelenberg, 1980 Human:case study A 30-year-old woman with a 2-year history of depression received 100 mg of tyrosine per kg of body weight per day for 2 weeks. Tyrosine caused marked improvement in the woman’s depression.
   van Praag, 1983 Hypothesis None. Tyrosine may possess antidepressant properties via its role as a precursor for catecholamines (dopamine and norepinephrine). Tyrosine may also potentiate the effects of 5-HTP on depression.
   No Author, 2007 Review None. Tyrosine may be particularly helpful in a subset of depressed patients with a deficiency in brain norepinephrine who fail to respond to conventional antidepressant medication except amphetamines.
   Gelenberg, 1982 Review None. Some cases of depression are caused by inadequate norepinephrine activity at brain centers that control mood. Tyrosine is a precursor for norepinephrine production. Preliminary trials of supplemental tyrosine in depressed patients have produced promising results.
   Peer-Reviewed Professional Journals

   · Gelenberg, A. J., et al. Tyrosine for the treatment of depression. American Journal of Psychiatry. 137(5):622-623, 1980.

   A 30-year-old female with a two-year history of depression showed marked improvement after two weeks of treatment with tyrosine (100 mg per kg of bodyweight (7,000 mg total) per day in three divided doses).

   · Gelenberg, A. J., et al. Tyrosine for depression. J Psychiatr Res. 17(2):175-180, 1982.

   The catecholamine hypothesis of affective disorders postulates that depression reflects inadequate norepinephrine activity at unspecified brain centers that regulate mood. In light of experimental data showing that the oral administration of tyrosine, precursor of the catecholamine series of neurotransmitters, can increase brain norepinephrine concentrations and activity, the authors have conducted preliminary trials of tyrosine in depressed outpatients. Initial results are encouraging, and they are now conducting a double-
   blind, parallel-group trial comparing tyrosine to the tricyclic antidepressant imipramine and to placebo in non-
   bipolar outpatients with major depression.

   · Gelenberg, A. J., et al. Tyrosine for the treatment of depression. Adv Biol Psychiat. 10:148-159, 1983.

   [no abstract available.]

   · Goldberg, I. K. L-tyrosine in depression. Lancet. 2(8190):364, 1980.

   [no abstract available].

   · McLean, A., et al. The effects of tyrosine depletion in normal healthy volunteers: implications for unipolar depression. Psychopharmacology (Berl). 171(3):286-297, 2004.

   Department of Psychiatry, University of Cambridge, School of Clinical Medicine, Addenbrooke’s Hospital, Cambridge, UK.

   In recent years, there has been a growing interest in the role of dopamine (DA) both in the pathogenesis of unipolar depression and in motivated behaviour. The innovative technique of acute tyrosine depletion presents an opportunity to characterise further its function in these domains. The present study examined the physiological, subjective and cognitive effects of acute tyrosine depletion in healthy volunteers. A double-
   blind, placebo-controlled, parallel group design was employed. Half of the participants ingested a balanced amino-acid mixture (BAL) and the other half received an identical mixture except that tyrosine and phenylalanine were absent (TYR-free). Plasma amino acid concentrations and subjective ratings were monitored at both baseline (T(0)) and 5 h following consumption (T(5)) of the mixtures. A comprehensive neuropsychological test battery was also administered at T(5). Relative to the BAL group, the reduction in TYR availability to the brain was more marked in the TYR-free group. Employment of psychological rating scales revealed that, compared with the BAL group, the TYR-free group became less content and more apathetic. For the affective go/no-go task, whilst the BAL group exhibited a happy latency bias, the TYR-free group demonstrated a sad latency bias. Furthermore, in the decision-making task, the rate at which the TYR-free group increased their bets in response to more likely outcomes was lower than that of the BAL group. Taken together, these neuropsychological findings strikingly paralleled those reported in previous investigations of unipolar depression. The experimental groups could not be differentiated on any of the other neuropsychological measures, including more classical assessments of fronto-executive function. These findings are consistent with the hypothesis that dopaminergic factors are particularly involved in disrupted affect/reward-based processing characteristic of clinical depression.

   · Meyers, S. Use of neurotransmitter precursors for treatment of depression. Alternative Medicine Review. 5(1):64-71, 2000.

   Tyrosine appears to potentiate the anti-depressant activity of 5-HTP.

   · Mouret, J., et al. [L-tyrosine cures, immediate and long term, dopamine-dependent depressions. Clinical and polygraphic studies]. C R Acad Sci III. 306(3):93-98, 1988.
   Like · Commented on by Mónika Mező · 1 min

   Peak Girls Twelve patients with polysommographic and clinical signs of dopamine-dependent depression (DDD) received, after a short-lasting trial with the dopamine agonist Piribedil, a treatment with oral-tyrosine (3,200 mg/day). On the very first day of treatment a return to mood, as judged by clinical impression and MADRS scores was observed. Sleep recordings performed on nights following days 1, 2, 7 and 8 of treatment showed an immediate improvement of those sleep parameters differentiating the more clearly DDD from other types of depression. More than 50 patients have now been treated successfully for periods ranging from a few months to almost 2 years. This treatment is ineffective in other types of depression.

   · van Praag, H. M. In search of the mode of action of antidepressants. 5-HTP/tyrosine mixtures in depressions. Neuropharmacology. 22(3 Spec No):433-440, 1983.

   For a long time antidepressants have been considered to act via enhancement of central monoaminergic activity (due to reuptake or MAO inhibition). An alternative hypothesis holds that their action is based on down-regulation of monoaminergic activity (due to decrease in density or sensitivity of certain receptor populations). In this paper the likelihood of both hypotheses is discussed and the conclusion reached that the first one is the most plausible. The following arguments are discussed: (1) the 5-HT precursor 5-HTP, which is transformed to 5-HT in the brain, has antidepressant properties; (2) there are indications that the same holds true for tyrosine, a catecholamine precursor transformed in the brain to DA and NA; and (3) evidence was found that the effects of 5-HTP in depression are potentiated by tyrosine. Since activation rather than suppression of monoaminergic activity seems to be linked to antidepressant activity, it seems likely that the signs of decreased monoamine metabolism that have been demonstrated in certain types of depression are the expression of a primary metabolic deficit rather than a phenomenon secondary to receptor hypersensitivity. Further clinical studies of 5-HT/CA precursor combinations in depression are justified.

   · Monograph: L-tyrosine. Alternative Medicine Review. 12(4):364-368, 2007.

   The role of tyrosine as a precursor for norepinephrine and dopamine synthesis has prompted research on its efficacy as an antidepressive agent. Tyrosine may be particularly helpful in a subset of depressed patients with a deficiency in brain norepinephrine who fail to respond to conventional antidepressant medication except amphetamines.

   Laypersons’ Publications

   · Braverman, Eric R. The Healing Nutrients Within. Keats Publishing, New Canaan, Connecticut, USA. 1997:61.

   Some cases of depression may benefit from singular therapy with tyrosine (1,000 – 2,000 mg per day).

   · Brown, D., et al. Natural remedies for depression. Nutrition Science News. 13(2), 1999.

   · Chaitow, Leon. Amino Acids in Therapy. Thorsons Publishers, Northamptonshire, United Kingdom. 1985:78.

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