Serotonin release measured in the human brain: a PET study with [11C]CIMBI-36 and d-amphetamine challenge

David Erritzoe*, Abhishekh H. Ashok, Graham E. Searle, Alessandro Colasanti, Samuel Turton, Yvonne Lewis, Mickael Huiban, Sara Moz, Jan Passchier, Azeem Saleem, John Beaver, Anne Lingford-Hughes, David J. Nutt, Oliver D. Howes, Roger N. Gunn, Gitte M. Knudsen, Eugenii A. Rabiner

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)


Positron emission tomography (PET) enables non-invasive estimation of neurotransmitter fluctuations in the living human brain. While these methods have been applied to dopamine and some other transmitters, estimation of 5-hydroxytryptamine (5-HT; Serotonin) release has proved to be challenging. Here we demonstrate the utility of the novel 5-HT2A receptor agonist radioligand, [11C]CIMBI-36, and a d-amphetamine challenge to evaluate synaptic 5-HT changes in the living human brain. Seventeen healthy male volunteers received [11C]CIMBI-36 PET scans before and 3 h after an oral dose of d-amphetamine (0.5 mg/kg). Dynamic PET data were acquired over 90 min, and the total volume of distribution (VT) in the frontal cortex and the cerebellum derived from a kinetic analysis using MA1. The frontal cortex binding potential (BPND frontal) was calculated as (VT frontal/VT cerebellum) − 1. ∆BPND frontal = 1 − (BPND frontal post-dose/BPND frontal baseline) was used as an index of 5-HT release. Statistical inference was tested by means of a paired Students t-test evaluating a reduction in post-amphetamine [11C]CIMBI-36 BPND frontal. Following d-amphetamine administration, [11C]CIMBI-36 BPND frontal was reduced by 14 ± 13% (p = 0.002). Similar effects were observed in other cortical regions examined in an exploratory analysis. [11C]CIMBI-36 binding is sensitive to synaptic serotonin release in the human brain, and when combined with a d-amphetamine challenge, the evaluation of the human brain serotonin system in neuropsychiatric disorders, such as major depression and Parkinson’s disease is enabled.

Original languageEnglish
Publication statusPublished - 1 Jan 2019


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