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MicroPET imaging of 5-HT1A receptors in rat brain: a test–retest [18F]MPPF study

  • Nicolas Aznavour
  • Chawki Benkelfat
  • Paul Gravel
  • Antonio Aliaga
  • Pedro Rosa-Neto
  • Barry Bedell
  • Luc Zimmer
  • Laurent Descarries
Original Article

Abstract

Purpose

Earlier studies have shown that positron emission tomography (PET) imaging with the radioligand [18F]MPPF allows for measuring the binding potential of serotonin 5-hydroxytryptamine1A (5-HT1A) receptors in different regions of animal and human brain, including that of 5-HT1A autoreceptors in the raphe nuclei. In the present study, we sought to determine if such data could be obtained in rat, with a microPET (R4, Concorde Microsystems).

Methods

Scans from isoflurane-anaesthetised rats (n = 18, including six test–retest) were co-registered with magnetic resonance imaging data, and binding potential, blood to plasma ratio and radiotracer efflux were estimated according to a simplified reference tissue model.

Results

Values of binding potential for hippocampus (1.2), entorhinal cortex (1.1), septum (1.1), medial prefrontal cortex (1.0), amygdala (0.8), raphe nuclei (0.6), paraventricular hypothalamic nucleus (0.5) and raphe obscurus (0.5) were comparable to those previously measured with PET in cats, non-human primates or humans. Test–retest variability was in the order of 10% in the larger brain regions (hippocampus, medial prefrontal and entorhinal cortex) and less than 20% in small nuclei such as the septum and the paraventricular hypothalamic, basolateral amygdaloid and raphe nuclei.

Conclusions

MicroPET brain imaging of 5-HT1A receptors with [18F]MPPF thus represents a promising avenue for investigating 5-HT1A receptor function in rat.

Keywords

Binding potential Serotonin receptors Brain imaging Autoreceptors Positron emission tomography 

Notes

Acknowledgments

The authors are grateful to Shadreck Mzengeza for his help with the radiochemistry. The work was funded by the Canadian Institutes for Health Research (operating grants to C.B. and L.D.). N.A. held a postdoctoral fellowship, and L.D. benefitted from an infrastructure grant from the Fonds de la Recherche en Santé du Québec.

Conflict of interest

The authors declare that they have no competing financial interests.

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Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Nicolas Aznavour
    • 1
    • 10
  • Chawki Benkelfat
    • 1
    • 2
  • Paul Gravel
    • 1
    • 2
  • Antonio Aliaga
    • 3
  • Pedro Rosa-Neto
    • 4
  • Barry Bedell
    • 2
    • 3
  • Luc Zimmer
    • 5
    • 6
  • Laurent Descarries
    • 7
    • 8
    • 9
  1. 1.Department of PsychiatryMcGill UniversityMontrealCanada
  2. 2.Department of Neurology and NeurosurgeryMcGill UniversityMontrealCanada
  3. 3.Department of Small Animal Imaging LaboratoryMcGill UniversityMontrealCanada
  4. 4.Molecular NeuroImaging LaboratoryDouglas HospitalMontrealCanada
  5. 5.ANIMAGE DepartmentCERMEPLyonFrance
  6. 6.Université Lyon 1 and CNRSLyonFrance
  7. 7.Department of Pathology and Cell BiologyUniversité de MontréalMontrealCanada
  8. 8.Department of PhysiologyUniversité de MontréalMontrealCanada
  9. 9.GRSNCUniversité de MontréalMontrealCanada
  10. 10.EPFL, SV, BMILaboratory of Neuroenergetics and Cellular DynamicsLausanneSwitzerland

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