The role of serotonin for gastrointestinal symptoms: Acute tryptophan depletion increases nausea

Acute tryptophan depletion (ATD) is an experimental model to reduce central serotonin levels. It has been shown to induce gastrointestinal symptoms in IBS patients. We wondered whether ATD can induced nausea in healthy subjects during motion. Methods: 38 healthy female subjects were screened for motion sickness susceptibility (MSSQ) and randomly assigned to two groups (ATD and placebo) in a double blinded design. They received either a protein drink without tryptophan (but substituted by other amino acids) (ATD condition) or a balanced protein drink tryptophan (placebo condition). Four hours after its consumptio…