Comparison of 50- and 100-g l-tryptophan depletion and loading formulations for altering 5-HT synthesis: pharmacokinetics, side effects, and mood states

Dougherty, Donald M.; Marsh-Richard, Dawn M.; Mathias, Charles W.; Hood, Ashley J.; Addicott, Merideth A.; Moeller, F. Gerard; Morgan, Christopher J.; Badawy, Abdulla A.-B.

doi:10.1007/s00213-008-1163-2

Cited by 34 publications

(81 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As in previous studies (Dougherty et al, 2007; Dougherty et al, 2008b; Dougherty et al, 2010), both formulations included: L-alanine 2.75 g; L-arginine 2.45 g; L-cysteine 1.35 g; Glycine 1.60 g; L-histidine 1.6 g; L-isoleucine 4.00 g; L-leucine 6.75 g; L-lysine HCl 4.45 g; L-methionine 1.5 g; L-phenylalanine 2.85 g; L-proline 6.10 g; L-serine 3.45 g; L-threonine 3.25 g; L-tyrosine 3.45 g; and L-valine 4.55 g. The tryptophan-balanced control mixture included 5.15 g of L-tryptophan. To increase palatability, these formulations were mixed with 1 g saccharin, 2.5 g of sugar-free powdered fruit drink mix, and 0.2 L of chilled filtered water, and L-cysteine and L-methionine were administered in gelatin capsules.…”

Section: Methodssupporting

confidence: 53%

Effects of tryptophan depletion and a simulated alcohol binge on impulsivity.

Dougherty¹,

Mullen²,

Hill‐Kapturczak³

et al. 2015

Experimental and Clinical Psychopharmacology

Self Cite

View full text Add to dashboard Cite

Background Researchers have suggested that binge drinkers experience disproportionate increases in impulsivity during the initial period of drinking, leading to a loss of control over further drinking, and that serotonergic mechanisms may underlie such effects. Methods We examined the effects of a simulated-alcohol binge and tryptophan depletion on three types of impulsivity: response initiation (IMT task), response inhibition (GoStop task), and delay discounting (SKIP task), and tested whether observed effects were related to “real world” binge drinking. 179 adults with diverse drinking histories completed a within-subject crossover design over 4 experimental days. Each day, participants underwent one of four test conditions: tryptophan depletion/alcohol, tryptophan depletion/placebo, tryptophan balanced control/alcohol, or tryptophan balanced control/placebo. The simulated binge involved consuming 0.3 g/kg of alcohol at 5, 6, and 7 hours after consuming the tryptophan depletion/balanced mixture. Impulsivity was measured before and after each drink. Results Relative to the placebo beverage condition, when alcohol was consumed, impulsive responding was increased at moderate and high levels of intoxication on the IMT and GoStop, but only at high levels of intoxication on the SKIP. Tryptophan depletion had no effect on impulsivity measured under either placebo or alcohol beverage conditions. Effects of alcohol and tryptophan manipulations on impulsivity were unrelated to patterns of binge drinking outside the laboratory. Conclusion The effects of alcohol consumption on impulsivity depend on the component of impulsivity being measured and the dose of alcohol consumed. Such effects do not appear to be a result of reduced serotonin synthesis. Additionally, “real world” binge drinking behaviors were unrelated to behavioral changes observed in the laboratory.

show abstract

Section: Methodssupporting

confidence: 53%

Effects of tryptophan depletion and a simulated alcohol binge on impulsivity.

Dougherty¹,

Mullen²,

Hill‐Kapturczak³

et al. 2015

Experimental and Clinical Psychopharmacology

Self Cite

View full text Add to dashboard Cite

show abstract

“…My colleagues and I 89 found that 25 g, 50 g, 75 g and 100 g mixtures reduced human plasma tryptophan by 42%, 60%, 65% and 64%, respectively. Dougherty and colleagues 90 also found a more robust depletion with a 100 g mixture than a 50 g mixture. However, the 2 mixtures caused similar lowing of mood -the 100 g mixture caused greater attrition -even though ratings of somatic symptoms were similar in the 2 groups.…”

Section: Theory and Practice In Depleting Tryptophan: What Is The Besmentioning

confidence: 91%

Acute tryptophan depletion in humans: a review of theoretical, practical and ethical aspects

Young

2013

J Psychiatry Neurosci

View full text Add to dashboard Cite

“…5-hydroxyindolacetic acid is a metabolite of serotonin which reflects central nervous system serotonin turnover [28]. On the other hand, a decrease in Trp availability can lead to a substantial lowering of serotonin synthesis and turnover [29][30][31]. Therefore, neuronal serotonin synthesis is strictly linked to Trp availability in cerebrospinal fluid [32], which depends in turn on plasma Trp/LNAA ratio, as already mentioned above [17,18].…”

Section: Aromatic Amino Acids: Biochemical and Nutritional Aspectsmentioning

confidence: 90%

“…Trpfree drinks cause a rise in total plasma amino acid concentration, which in turn induces protein synthesis. Available plasma free-Trp is incorporated into new synthesized proteins and as a consequence its level in blood and tissues falls [31,43]. At the same time, brain Trp uptake is reduced and serotonin synthesis is downmodulated [32].…”

Section: Altered Intake Of Aromatic Amino Ac-ids and Psychoactive Effmentioning

confidence: 99%

See 1 more Smart Citation

The Psychoactive Effects of Aromatic Amino Acids

Ghirri¹,

Cannella²,

Bignetti

2011

CNF

View full text Add to dashboard Cite

Protein synthesis is considered the major pathway for the final utilization of amino acids, however amino acids also enter as key precursors in many other metabolic processes. For instance, the aromatic amino acids (AAA) tryptophan and tyrosine (or phenylalanine) are precursors of serotonin and catecholamines, respectively. By using AAA-enriched or AAA-deprived diets, the key role of serotonin and catecholamines in modulating some aspects of mood, cognition, social interactions and perhaps eating behaviour was demonstrated.

show abstract

Comparison of 50- and 100-g l-tryptophan depletion and loading formulations for altering 5-HT synthesis: pharmacokinetics, side effects, and mood states

Abstract: There are important considerations when choosing among formulation sizes for use in Trp manipulation studies, and the complete 7-h time-course data set of the typical plasma Trp measures presented here may help researchers decide which methodology best suits their needs.

Cited by 34 publications

References 54 publications

Effects of tryptophan depletion and a simulated alcohol binge on impulsivity.

Effects of tryptophan depletion and a simulated alcohol binge on impulsivity.

Acute tryptophan depletion in humans: a review of theoretical, practical and ethical aspects

The Psychoactive Effects of Aromatic Amino Acids

Contact Info

Product

Resources

About