Positron emission tomography of 5-HT transporter sites in the baboon brain with [11C]McN5652

Zsolt Szabo, Ursula Scheffel, Makiko Suehiro, Robert F. Dannais, Sang Eun Kim, Hayden T. Ravert, George A. Ricaurte, Henry N. Wagner

Research output: Contribution to journalArticlepeer-review

66 Scopus citations


[11C]McN5652 is a new radioligand specific for 5-hydroxytryptamine (5-HT; serotonin) transporters. In this study we used [11C]McN5652 to image the 5-HT transporter sites in baboon brain by positron emission tomography (PET). Dynamic PET studies were performed in three Papio anubis baboons. The animals were injected intravenously first with 11C-labeled (+)-McN5652([11C](+)McN5652), then with pharmacologically inactive enantiomer 11C-labeled (-)-McN5652 ([11C](-)McN5652); two animals received a third study with [11C](+)McN5652 after pretreatment with the specific 5-HT uptake site inhibitor fluoxetine (5 mg/kg). Initial uptake into the brain was similar for both [11C](+)McN5652 and [11C](-)McN5652. At later times (45-120 min after injection), only [11C](+)McN5652 showed a distribution characteristic for 5-HT uptake sites. In contrast, in studies with [11C](-)McN5652 and in those with [11C](+)McN5652 after 5-HT uptake site blockade with fluoxetine, 11C radioactivity concentrations were significantly lower and the distribution pattern was relatively even. The differences between [11C](+)-and (-)McN5652 were calculated for the time interval 95-125 min postinjection and used to estimate specific binding. Specific binding correlated well (r = 0.95, p < 0.001) with the known density of 5-HT uptake sites in human brain. These results indicate that [11C](+)McN5652 is suitable for PET imaging of 5-HT uptake sites in primate brain.

Original languageEnglish (US)
Pages (from-to)798-805
Number of pages8
JournalJournal of Cerebral Blood Flow and Metabolism
Issue number5
StatePublished - 1995


  • Fluoxetine
  • Papio anubis
  • Positron emission tomography
  • Serotonin uptake sites
  • [C]McN5652

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology
  • Cardiology and Cardiovascular Medicine


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