Plasma-Tryptophan Levels in Depression

Aylward, Mansel; Maddock, J.

doi:10.1016/s0140-6736(73)91389-5

Cited by 35 publications

(7 citation statements)

References 7 publications

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“…levels change in response to a number of factors (Tagliamonte et al, 1971 b;Korf et al, 1972;Aylward and Maddock, 1973;. The use of normal subjects on no medication in this study minimized such possible effects with the exception of that of heparin.…”

Section: Discussionmentioning

confidence: 94%

Plasma Trytophan and Sleep

Chen¹,

Kalucy²,

Hartmann³

et al. 1974

BMJ

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Section: Discussionmentioning

confidence: 94%

Plasma Trytophan and Sleep

Chen¹,

Kalucy²,

Hartmann³

et al. 1974

BMJ

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“…A lower concentration of tryptophan in the CSF and a lower free pool of serum tryptophan have recently been described in depressive patients [1,4]. Recent data has also shown that sodimn salicylate can displace tryptophan from its plasma binding sites [16], as well as stimulate serotonin synthesis, in rat brain [21].…”

Section: Discussionmentioning

confidence: 96%

“…Recent data has also shown that sodimn salicylate can displace tryptophan from its plasma binding sites [16], as well as stimulate serotonin synthesis, in rat brain [21]. There is clinical evidence that sMicylate, as well as other similar anti-rheumatic drugs, exert antidepressive properties when evaluated with a psychiatric rating scale [1]. Our data therefore, point out the possibility that CPIB may exert antidepressant properties when administed alone or in combination with tryptophan, which is itself an anti-depressant [5].…”

Section: Discussionmentioning

confidence: 99%

Influence of clofibrate on serum triptophan in man

et al. 1974

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Summary. The effect of clofibrate on free and bound tryptophan levels was tested in 8 volunteers, 5 of whom were hospitalised. Comparing the effects of the drug, administered for 5 days, with those of a placebo, given for 5 further days, after an interval of 2 days, it was observed that clofibrate lowered total plasma tryptophan by 50--70~o in all subjects. The decrease is in the bound fraction and probably reflects a displacement due to the high protein binding affinity of the drug. At the same time plasma free tryptophan values increase significantly.These data confirm our previous observations in the rat, demonstrating a decrease of bound plasma tryptophan and an increase of brain tryptophan and 5-HIAA levels, and supporting the hypothesis that clofibrate increased the availability of tryptophan to brain tryptophan hydroxylase, thus stimulating serotonin synthesis.Key words: Clofibrate --Free and bound plasma tryptophan --Serotonin synthesis.Clofibrate (p-chlorophenoxyisobutyrate) (CPIB) is a commonly used drug for the management of hyperlipoproteinemias [2,15]. It is highly bound to plasma proteins and has a relatively long half-life, i.e. 10--14 hrs, in man [22]. It displaces oral anticoagulants from albumin binding sites [18]. It was our purpose to determine the drug's ability to displace tryptophan from its plasma binding sites, thus increasing the availability of free tryptophan. Tryptophan is, in fact, the only circulating amino acid highly bound to serum proteins [13]; the tryptophan pool in brain is controlled by the free fraction of serum tryptophan [11]. Moreover, there is ample evidence that the rate of synthesis of 5-hydroxytryptamine (5-HT) in brain is regulated principally by brain tryptophan, since the availability of this amino acid in the nervous tissues is considerably below the Km of the first enzyme in 5-tIT biosynthesis, tryptophan hydroxylase [8]. Treatments which cause increased synthesis of brain 5-HT all lead to significant increases in the concentration of brain tryptophan [20].

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“…The non-albumin-bound tryptophan of serum, the portion most readily available for transport across the blood-brain barrier, is low in some studies (6,21), but not in others (59,Ill). The significance of CSF tryptophan is also a matter of dispute; reports give the concentration as low (20) or normal (4).…”

Section: Tryptophan In Mental Depressionmentioning

confidence: 98%

Biochemistry of Mental Depression

Sourkes

1977

Canadian Psychiatric Association Journal

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Plasma-Tryptophan Levels in Depression

Cited by 35 publications

References 7 publications

Plasma Trytophan and Sleep

Plasma Trytophan and Sleep

Influence of clofibrate on serum triptophan in man

Biochemistry of Mental Depression

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