IngentaConnect Acute Tryptophan Depletion Alters Gastrointestinal and Anxiety Sy...

Authors: Shufflebotham, Jonathan¹; Hood, Sean²; Hendry, Julie³; Hince, Dana A.⁴; Morris, Kelly⁴; Nutt, David⁴; Probert, Chris¹; Potokar, John⁴

Source: The American Journal of Gastroenterology, Volume 101, Number 11, November 2006 , pp. 2582-2587(6)

Publisher: Blackwell Publishing

Abstract:

OBJECTIVES: To assess the effect of acute changes in serotonin (5-HT) synthesis using the acute tryptophan depletion (ATD) paradigm on gastrointestinal (GI) and mood symptoms in irritable bowel syndrome (IBS).

METHODS: In a randomized double-blind crossover study, 29 subjects (18 patients with ROME II defined IBS and 11 age-matched controls) were studied under ATD and acute tryptophan increase (ATI) conditions. GI symptoms, mood and anxiety ratings, as well as plasma tryptophan concentrations were measured.

RESULTS: Total (and free) plasma tryptophan concentrations decreased on the ATD day in patients (73%[82%]) and controls (73%[80%]), and increased on the ATI day in patients (59%[143%]) and controls (61%[381%]). Compared with the ATD day, IBS patients reported more GI symptoms on the ATI day at +210 (p < 0.001) and at +270 (p < 0.05) min post drink. IBS patients also reported less anxiety on the ATI day compared with the ATD day at +270 min (p < 0.001). ATD and ATI did not affect these ratings in control participants. IBS patients had a lower mood compared with controls (p < 0.05), but this did not differ between the ATI and ATD days in either group.

CONCLUSIONS: IBS patients' GI and anxiety responses to changes in tryptophan load differ from controls. This suggests a difference in serotonergic functioning between these two groups and provides evidence to support the hypothesis that 5-HT dysfunction is involved in IBS.

(Am J Gastroenterol 2006;101:2582-2587)

Document Type: Research article

DOI: 10.1111/j.1572-0241.2006.00811.x

Affiliations: 1: Clinical Science at South Bristol, University of Bristol, Bristol, United Kingdom 2: School of Psychiatry & Clinical Neurosciences, University of Western Australia, Perth, Australia 3: Bristol Royal Infirmary, Bristol, United Kingdom 4: Psychopharmacology Unit, University of Bristol, Bristol, United Kingdom

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Acute Tryptophan Depletion Alters Gastrointestinal and Anxiety Symptoms in Irritable Bowel Syndrome