ATD - A short summary
As TPH2 is not saturated at physiological concentrations of TRP, diminished substrate availability for TPH2 decreases brain 5-HT synthesis and release [Wurtmann et al 1980]. Serotonergic function can be temporarily suppressed by using ATD, a method commonly used in pharmacological and psychiatric research [Moore et al 2000, Mendelsohn et al 2009].
The limiting side effect of ATD in human studies is nausea that the amino acid mixture can cause. A modified mixture, ATD Moja-De, involves a body weight adapted administration of amino acids and lower concentration of methionine relative to conventional mixtures, which makes it less nauseating. Its use has proven to be a safe and effective method of TRP depletion even in children and adolescents [Demisch et al. 2002; Stadler et al. 2007; Zepf et al. 2009; Zepf et al. 2008; Zepf et al. 2008; Zepf et al. 2008; Zepf et al. 2009].
For a more detailed, hand-on guide of ATD please refer to Principles of Rapid Tryptophan Depletion and its Use in Research of Neuropsychiatric Disorders (F.D. Zepf, Amino Acids in Human Nutrition and Health, CAB International 2012).