Psychomotor, subjective and neuroendocrine effects of acute tryptophan depletion in the healthy volunteer

1990 ◽  
Vol 5 (1) ◽  
pp. 31-38 ◽  
Author(s):  
P Danjou ◽  
M Hamon ◽  
L Lacomblez ◽  
D Warot ◽  
S Kecskemeti ◽  
...  
Keyword(s):  
Amino Acids ◽  
Reaction Time ◽  
Healthy Volunteer ◽  
Subjective Effects ◽  
Acute Tryptophan Depletion ◽  
Tryptophan Depletion ◽  
Free Solution ◽  
Amino Acid Solution ◽  
Free Tryptophan ◽  
Recognition Reaction Time

SummaryThe effects of acute tryptophan depletion were investigated in 20 healthy volunteers. Ten of them received a balanced amino acid solution and 10 a tryptophan-free solution. The fall in tryptophan levels induced by the oral administration of a mixture tryptophan-free of L-amino acids was - 77% for free tryptophan and - 81% for total tryptophan. Before treatment, there were intergroup differences affecting alertness parameters (critical flicker threshold, recognition reaction time), plasma levels of prolactin and baseline performance in the proofreading correction test. In the tryptophan-depleted group, the number of errors reported during the unpleasant sound signal was increased (+ 48%) after treatment, whereas the number of errors fell (— 15%) in the group receiving the tryptophan supplement. Conversely the levels of prolactin were correlated with those of serum tryptophan. Few subjective effects were reported.

scholarly journals Acute tryptophan depletion in accordance with body weight: influx of amino acids across the blood–brain barrier

2012 ◽  
Vol 119 (9) ◽  
pp. 1037-1045 ◽  
Author(s):  
V. L. S. Dingerkus ◽  
T. J. Gaber ◽  
K. Helmbold ◽  
S. Bubenzer ◽  
A. Eisert ◽  
...  
Keyword(s):  
Amino Acids ◽  
Body Weight ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Acute Tryptophan Depletion ◽  
Tryptophan Depletion ◽  
Blood Brain

Acute tryptophan depletion in bulimia: Effects on large neutral amino acids

1994 ◽  
Vol 35 (6) ◽  
pp. 388-397 ◽  
Author(s):  
Theodore E. Weltzin ◽  
John D. Fernstrom ◽  
Claire McConaha ◽  
Walter H. Kaye
Keyword(s):  
Amino Acids ◽  
Acute Tryptophan Depletion ◽  
Tryptophan Depletion ◽  
Large Neutral Amino Acids ◽  
Neutral Amino Acids

Acute tryptophan depletion in schizophrenia

2001 ◽  
Vol 31 (1) ◽  
pp. 75-84 ◽  
Author(s):  
K. L. GOLIGHTLY ◽  
J. A. LLOYD ◽  
J. E. HOBSON ◽  
P. GALLAGHER ◽  
G. MERCER ◽  
...  
Keyword(s):  
Movement Disorders ◽  
Acute Tryptophan Depletion ◽  
Tryptophan Depletion ◽  
Double Blind ◽  
Free Tryptophan ◽  
Schizophrenic Patients ◽  
Axis I ◽  
Dsm Iv ◽  
Mood And Cognition ◽  
New Generation

Background. Brain 5-hydroxytryptamine (5-HT) function is implicated in the pathophysiology of schizophrenia and the action of new generation antipsychotic drugs. By the method of acute tryptophan depletion (ATD) 5-HT can be selectively manipulated. The aim of this study was to examine the effects of ATD on symptoms, mood and cognition in schizophrenic patients.Methods. Twenty-eight schizophrenic patients participated in a within subject, double-blind, placebo-controlled counterbalanced cross-over study. Patients with a concurrent DSM-IV axis I diagnosis were excluded. Symptoms, mood and cognitive function were evaluated following ATD or ingestion of a control drink.Results. The depleting drink significantly reduced plasma total and free tryptophan. Tryptophan/LNAA ratios did not alter with the administration of the control drink, but differed significantly with ATD; however there was no significant change in tyrosine/LNAA ratio. ATD led to impairment in executive function that was dependent upon the order of administration. Tests of sustained attention, speed of processing, and everyday memory were not affected. No effects were observed on subjective mood ratings, movement disorders or PANSS scores.Conclusions. Acute tryptophan depletion selectively alters cognition in schizophrenia, but has no effect on symptoms, mood ratings or movement disorders.

scholarly journals Enzymatic Preparation of Bioactive Peptides Exhibiting ACE Inhibitory Activity from Soybean and Velvet Bean: A Systematic Review

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3822
Author(s):  
Azis Boing Sitanggang ◽  
Jessica Eka Putri ◽  
Nurheni Palupi ◽  
Emmanuel Hatzakis ◽  
Elvira Syamsir ◽  
...  
Keyword(s):  
Systematic Review ◽  
Amino Acids ◽  
Reaction Time ◽  
Hydrolytic Activity ◽  
Converting Enzyme ◽  
Enzymatic Preparation ◽  
Angiotensin I ◽  
Velvet Bean ◽  
Angiotensin I Converting Enzyme ◽  
Aspergillus Sp

The Angiotensin-I-converting enzyme (ACE) is a peptidase with a significant role in the regulation of blood pressure. Within this work, a systematic review on the enzymatic preparation of Angiotensin-I-Converting Enzyme inhibitory (ACEi) peptides is presented. The systematic review is conducted by following PRISMA guidelines. Soybeans and velvet beans are known to have high protein contents that make them suitable as sources of parent proteins for the production of ACEi peptides. Endopeptidase is commonly used in the preparation of soybean-based ACEi peptides, whereas for velvet bean, a combination of both endo- and exopeptidase is frequently used. Soybean glycinin is the preferred substrate for the preparation of ACEi peptides. It contains proline as one of its major amino acids, which exhibits a potent significance in inhibiting ACE. The best enzymatic treatments for producing ACEi peptides from soybean are as follows: proteolytic activity by Protease P (Amano-P from Aspergillus sp.), a temperature of 37 °C, a reaction time of 18 h, pH 8.2, and an E/S ratio of 2%. On the other hand, the best enzymatic conditions for producing peptide hydrolysates with high ACEi activity are through sequential hydrolytic activity by the combination of pepsin-pancreatic, an E/S ratio for each enzyme is 10%, the temperature and reaction time for each proteolysis are 37 °C and 0.74 h, respectively, pH for pepsin is 2.0, whereas for pancreatin it is 7.0. As an underutilized pulse, the studies on the enzymatic hydrolysis of velvet bean proteins in producing ACEi peptides are limited. Conclusively, the activity of soybean-based ACEi peptides is found to depend on their molecular sizes, the amino acid residues, and positions. Hydrophobic amino acids with nonpolar side chains, positively charged, branched, and cyclic or aromatic residues are generally preferred for ACEi peptides.

Availability of amino acids supplied by constant intravenous infusion of synthetic dipeptides in healthy man

1989 ◽  
Vol 76 (6) ◽  
pp. 643-648 ◽  
Author(s):  
S. Albers ◽  
J. Wernerman ◽  
P. Stehle ◽  
E. Vinnars ◽  
P. Fürst
Keyword(s):  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Metabolic Clearance ◽  
Amino Acid Solution ◽  
Appreciable Change ◽  
Total Body ◽  
Hydrolysis Of ◽  
Firm Evidence ◽  
Apparently Healthy

1. A commercial amino acid solution supplemented with two synthetic dipeptides, l-alanyl-l-glutamine (Ala-Gln) and glycyl-l-tyrosine (Gly-Tyr), or alternatively with isonitrogenous amounts of free alanine and glycine has been continuously infused over 4 h in six apparently healthy volunteers. 2. The infusion of the solutions was not accompanied by any side effects and the volunteers reported no complaints. 3. Infusion of the alanine- and glycine-supplemented control solution resulted in an increase of the concentration of these amino acids, while no appreciable change in free glutamine concentration was observed and free tyrosine revealed a steady decrease throughout the infusion. 4. Infusion of the peptide-supplemented solution resulted in a prompt equimolar liberation of the constituent free amino acids (glutamine, alanine, tyrosine and glycine), approaching steady state after about 30 min infusion, while only trace but stable concentrations of the two dipeptides were measured throughout the infusion. No peptides were detectable in urine. The findings suggest a nearly quantitative extracellular hydrolysis of the infused dipeptides and indicate a subsequent utilization of the liberated free amino acids. 5. The estimated metabolic clearance rates and total body plasma clearances were very similar for the two dipeptides (Ala-Gln 35.9 ± 9.5 ml min−1 kg−1 and 2.9 ± 0.9 1/min, respectively; Gly-Tyr 33.7 ± 9.5 ml min−1 kg−1 and 2.7 ± 0.9 1/min, respectively); thus there is little difference in the metabolic handling of these dipeptides. 6. The study provides firm evidence that the synthetic dipeptides Ala-Gln and Gly-Tyr are quantitatively hydrolysed and that these peptides can be used as a safe and efficient source of free glutamine and tyrosine as part of a commercial solution.

scholarly journals Ingesting a pre-workout supplement containing caffeine, B-vitamins, amino acids, creatine, and beta-alanine before exercise delays fatigue while improving reaction time and muscular endurance

2012 ◽  
Vol 9 (1) ◽  
pp. 28 ◽  
Author(s):  
Brandon D Spradley ◽  
Kristy R Crowley ◽  
Chih-Yin Tai ◽  
Kristina L Kendall ◽  
David H Fukuda ◽  
...  
Keyword(s):  
Amino Acids ◽  
Reaction Time ◽  
B Vitamins ◽  
Muscular Endurance ◽  
Beta Alanine

scholarly journals Effects of lowered serotonin transmission on cocaine-induced striatal dopamine response: PET [11C]raclopride study in humans

2011 ◽  
Vol 199 (5) ◽  
pp. 391-397 ◽  
Author(s):  
Sylvia M. L. Cox ◽  
Chawki Benkelfat ◽  
Alain Dagher ◽  
J. Scott Delaney ◽  
France Durand ◽  
...  
Keyword(s):  
Substance Use ◽  
Substance Use Disorders ◽  
Striatal Dopamine ◽  
Emission Tomography ◽  
Acute Tryptophan Depletion ◽  
Tryptophan Depletion ◽  
Comorbid Conditions ◽  
Drug Craving ◽  
Positron Emission ◽  
Wide Range

BackgroundLow serotonin transmission is thought to increase susceptibility to a wide range of substance use disorders and impulsive traits.AimsTo investigate the effects of lowered serotonin on cocaine-induced (1.0 mg/kg cocaine, self-administered intranasally) dopamine responses and drug craving.MethodIn non-dependent cocaine users, serotonin transmission was reduced using the acute tryptophan depletion method. Striatal dopamine responses were measured using positron emission tomography with [11C]raclopride.ResultsAcute tryptophan depletion increased drug craving and striatal dopamine responses to cocaine. These acute tryptophan depletion-induced increases did not occur in the absence of cocaine.ConclusionsThe results suggest that low serotonin transmission can increase dopaminergic and appetitive responses to cocaine. These findings might identify a mechanism by which individuals with low serotonin are at elevated risk for both substance use disorders and comorbid conditions.

Sign in / Sign up

Export Citation Format

Share Document