AMPT-induced monoamine depletion in humans: Evaluation of two alternative [123I]IBZM SPECT procedures

Erik Boot*, Jan Booij, Gregor Hasler, Janneke R. Zinkstok, Lieuwe De Haan, Don H. Linszen, Thérèse A. Van Amelsvoort

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

26 Citations (Scopus)


Purpose: Acute monoamine depletion paradigms using alpha-methyl-para- tyrosine (AMPT) combined with single photon emission computed tomography (SPECT) have been used successfully to evaluate disturbances in central dopaminergic neurotransmission. However, severe side effects due to relatively high doses (4,500 to 8,000 mg) of AMPT have been reasons for study withdrawal. Thus, we assessed the effectiveness and tolerability of two alternative procedures, using lower doses of AMPT. Methods: Six healthy subjects underwent three measurements of striatal dopamine D2 receptor (D2R)-binding potential (BPND) with SPECT and the selective radiolabeled D2R antagonist [123I]IBZM. All subjects were scanned in the absence of pharmacological intervention (baseline) and after two different depletion procedures. In the first depletion session, over 6 h, subjects were administered 1,500 mg of AMPT before scanning. In the second depletion session, over 25 h, subjects were administered 40 mg AMPT/kg body weight. We also administered the Subjective Well-being Under Neuroleptic Treatment Scale, a self-report instrument designed to measure the subjective experience of patients on neuroleptic medication. Results: We found no change of mean D2R BPND after the first and short AMPT challenge compared to the baseline. However, we found a significant increase in striatal D2R BPND binding after the AMPT challenge adjusted for bodyweight compared to both other regimen. Although subjective well-being worsened after the prolonged AMPT challenge, no severe side effects were reported. Conclusions: Our results imply a low-dosage, suitable alternative to the common AMPT procedure. The probability of side effects and study withdrawal can be reduced by this procedure.

Original languageEnglish
Pages (from-to)1350-1356
Number of pages7
JournalEuropean Journal of Nuclear Medicine and Molecular Imaging
Issue number7
Publication statusPublished - 1 Jul 2008
Externally publishedYes


  • [I]IBZM
  • AMPT
  • Dopamine
  • SWN


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