title: MicroPET imaging of 5-HT 1A receptors in rat brain: a test-retest [18F]MPPF study.
abstract: OBJECTIVE
  Earlier studies have shown that positron emission tomography (PET) imaging with the radioligand [(18)F]MPPF allows for measuring the binding potential of serotonin 5-hydroxytryptamine(1A) (5-HT(1A)) receptors in different regions of animal and human brain, including that of 5-HT(1A) 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-HT(1A) receptors with [(18)F]MPPF thus represents a promising avenue for investigating 5-HT(1A) receptor function in rat.
authors.affiliation: Department of Psychiatry, McGill University, Montreal, QC, Canada. nicolas.aznavour@epfl.ch
authors.forename: Nicolas
authors.initials: N
authors.lastname: Aznavour
authors.forename: Chawki
authors.initials: C
authors.lastname: Benkelfat
authors.forename: Paul
authors.initials: P
authors.lastname: Gravel
authors.forename: Antonio
authors.initials: A
authors.lastname: Aliaga
authors.forename: Pedro
authors.initials: P
authors.lastname: Rosa-Neto
authors.forename: Barry
authors.initials: B
authors.lastname: Bedell
authors.forename: Luc
authors.initials: L
authors.lastname: Zimmer
authors.forename: Laurent
authors.initials: L
authors.lastname: Descarries
mesh_terms: D000818:Animals; D001921:Brain / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000378:metabolism*; D002415:Cats; D006801:Humans; D007267:Injections; D008297:Male; D010879:Piperazines / Q000008:administration & dosage; D049268:Positron-Emission Tomography; D011725:Pyridines / Q000008:administration & dosage; D011851:Radioactivity; D051381:Rats; D044282:Receptor, Serotonin, 5-HT1A / Q000378:metabolism*; D013997:Time Factors
chemical_list: D010879:Piperazines; D011725:Pyridines; D044282:Receptor, Serotonin, 5-HT1A; C416325:4-(2'-methoxyphenyl)-1-(2'-(N-2'-pyridinyl)-p-(18F)fluorobenzamido )ethylpiperazine