Imaging for metabotropic glutamate receptor subtype 1 in rat and monkey brains using PET with [18F]FITM

Eur J Nucl Med Mol Imaging. 2012 Apr;39(4):632-41. doi: 10.1007/s00259-011-1995-6. Epub 2011 Nov 24.


Purpose: In this study, we evaluate the utility of 4-[(18)F]fluoro-N-[4-[6-(isopropylamino)pyrimidin-4-yl]-1,3-thiazol-2-yl]-N-methylbenzamide ([(18)F]FITM) as a positron emission tomography (PET) ligand for imaging of the metabotropic glutamate receptor subtype 1 (mGluR1) in rat and monkey brains.

Methods: In vivo distribution of [(18)F]FITM in brains was evaluated by PET scans with or without the mGluR1-selective antagonist (JNJ16259685). Kinetic parameters of monkey PET data were obtained using the two-tissue compartment model with arterial blood sampling.

Results: In PET studies in rat and monkey brains, the highest uptake of radioactivity was in the cerebellum, followed by moderate uptake in the thalamus, hippocampus and striatum. The lowest uptake of radioactivity was detected in the pons. These uptakes in all brain regions were dramatically decreased by pre-administration of JNJ16259685. In kinetic analysis of monkey PET, the highest volume of distribution (V(T)) was detected in the cerebellum (V(T) = 11.5).

Conclusion: [(18)F]FITM has an excellent profile as a PET ligand for mGluR1 imaging. PET with [(18)F]FITM may prove useful for determining the regional distribution and density of mGluR1 and the mGluR1 occupancy of drugs in human brains.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autoradiography
  • Benzamides* / pharmacokinetics
  • Brain / cytology
  • Brain / diagnostic imaging*
  • Brain / metabolism*
  • Feasibility Studies
  • Haplorhini*
  • Male
  • Mice
  • Positron-Emission Tomography / methods*
  • Rats
  • Receptors, Metabotropic Glutamate / metabolism*
  • Thiazoles* / pharmacokinetics


  • 4-fluoro-N-(4-(6-(isopropylamino)pyrimidin-4-yl)-1,3-thiazol-2-yl)-N-methylbenzamide
  • Benzamides
  • Receptors, Metabotropic Glutamate
  • Thiazoles
  • metabotropic glutamate receptor type 1