Dopamine and Serotonin Metabolism in Hepatic Encephalopathy

Knell, A.J.; Davidson, Anne; Williams, Roger; Kantamaneni, B. D.; Curzon, G.

doi:10.1136/bmj.1.5907.549

Cited by 140 publications

(30 citation statements)

References 18 publications

(7 reference statements)

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“…No significant differences were found in the values of plasma total tryptophan, free tryptophan and f-Trp/t-Trp ratio in patients with liver cirrhosis, liver cirrhosis + hepatocellular carcinoma, hepatocellular carcinoma and liver cirrhosis with encephalopathy but no bleeding tendency compared with healthy controls. There are reports that plasma free tryptophan is significantly higher in liver cirrhosis (28), or hepatic encephalopathy of liver cirrhosis than in healthy controls (19,(29)(30)(31). These values were obtained, however, by measuring the tryptophan concentration in the filtrate after centrifugation without pH control, and without Separation of tryptophan from other amino acids and components related to tryptophan which might influence the fluorescence assay of tryptophan.…”

Section: Discussionmentioning

confidence: 99%

Determination of Free Tryptophan in Plasma and Its Clinical Applications

Hijikata¹,

Hara²,

Shiozaki³

et al. 1984

Clinical Chemistry and Laboratory Medicine

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Summary: Free tryptophan in plasma was separated by centrifugation through an Amicon Ultrafiltration membrane cone. The value obtained without control of pH was found to be lower than that obtained with control of pH by an improved method (Hijikata et al. (1981) Anal. Biochem. 118, 10-16).For determination of the total tryptophan concentration in the plasma, high performance liquid chromatography (HPLC) was better than the method of Denckla Dewey s modified by Bloxam & Warren ((1974) Anal. Biochem. 60,[621][622][623][624][625], s judged on the basis of sensitivity, recovery rate and coefficient of variance. The total tryptophan concentration in the plasma determined by HPLC was lower than that determined by theThe total tryptophan concentration (t-Trp), free tryptophan concentration (f-Trp) and f-Trp/t-Trp ratio were 55.8 ± 10.2 μιηοΐ/ΐ, 11.6 ± 1.5 μίηοΐ/ΐ and 0.211 ± 0.03 (mean ± l SD) respectively, in healthy subjects (co trols). No significant difference was observed between the values of controls and those of patients with liver cirrhosis, hepatocellular carcinoma, liver cirrhosis with hepatocellular carcinoma and hepatic encephalopathy of liver cirrhosis without bleeding. But in liver cirrhosis with bleeding, free tryptophan concentration (f-Trp, 48.0 ± 23.3 μτηοΐ/ΐ, p < 0.001) and f-Trp/t-Trp ratio (0.645 ± 0.289, p < 0.001) were significantly higher than those of controls. In fulminant hepatitis free tryptophan concentration, (f-Trp, 106.6 ± 79.9 μιηοΐ/ΐ, p < 0.02), and f-Trp/t-Trp ratio (0.973 ± 0.017, p < 0.001) were significantly higher than those of controls, and free tryptophan concentration (f-Trp) and f-Trp/t-Trp ratio (p < 0.005) were significantly higher than in liver cirrhosis with bleeding. In other words the increase of free tryptophan concentration in plasma may be related to the bleeding, and in fulminant hepatitis the binding ability of free tryptophan to albumin may decrease. In the examined cases of liver cirrhosis, the correlation of the concentration of plasma tryptophan with those of other amino acids and indicators of liver function was changed when hepatocellular carcinoma was also present.

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Section: Discussionmentioning

confidence: 99%

Determination of Free Tryptophan in Plasma and Its Clinical Applications

Hijikata¹,

Hara²,

Shiozaki³

et al. 1984

Clinical Chemistry and Laboratory Medicine

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“…Evidence has been shown that Trp usually occurs as bound to serum albumin in the circulation and the free Trp fraction in serum increases in patients with liver diseases, probably due to elevated free fatty acids and hypoalbuminemia (Ono et al 1978;Yoshida and Hirayama 1980). There are conflicting reports, however, that no consistent relationship could be observed between the plasma Trp level and increase of serotonin or its metabolites in the cerebrospinal fluid in patients with hepatic coma (Knell et al 1974;Lal et al 1975.). Thus the relationship of Trp and its metabolites to hepatic encephalopathy remains to be clarified.…”

mentioning

confidence: 91%

Tryptophan metabolism in liver cirrhosis: Influence of oral antibiotics on neuropsychiatric symptoms.

Yoshida

Hirayama

1984

Tohoku J. Exp. Med.

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Oral tryptophan loading tests were performed on patients with cirrhosis of the liver before and after treatment with an oral antibiotic practically unabsorbed from the gastrointestinal tract. After antibiotic therapy, neuropsychiatric manifestations evoked by the oral administration of tryptophan were reduced in duration by about 50% and in severity as well despite a slightly enhanced elevation of serum total and free typtophan levels, compared to pretreatment loading tests, The urinary indican output also showed a significantly greater decrease in the post-treatment test (p <0.05) whereas no appreciable difference was observed in urinary 5-hydroxy-indoleacetic acid excretion between the pre-and post-treatment tests. The data suggest that neuropsychiatric manifestations seen following oral administration of tryptophan may be attributed to intestinal tryptophan metabolites rather than to this aromatic amino acid itself and /or its metabolites in the brain. tryptophan loading ; neuropsychiatric manifestation ; total and free tryptophan ; urinary indican ; urinary 5-hydroxy-indoleacetic acid

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“…L-Dopa, Bupropion oder Kokain, delirante Zustände auslösen können [52,53]. Ebenfalls dürfte ein Dopaminüberschuss die Ursache für die Entwicklung deliranter Zustände im Rahmen einer hepatischen Enzephalopathie sein [54]. Andererseits sind klassische Neuroleptika, wie z.B.…”

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Neurobiologische und pathophysiologische Grundlagen des Delirs

Jenewein¹,

Büchi²

2007

Swiss Arch Neurol Psychiatr

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Dopamine and Serotonin Metabolism in Hepatic Encephalopathy

Cited by 140 publications

References 18 publications

Determination of Free Tryptophan in Plasma and Its Clinical Applications

Determination of Free Tryptophan in Plasma and Its Clinical Applications

Tryptophan metabolism in liver cirrhosis: Influence of oral antibiotics on neuropsychiatric symptoms.

Neurobiologische und pathophysiologische Grundlagen des Delirs

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