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PET study using [ 11C]FTIMD with ultra-high specific activity to evaluate I2-imidazoline receptors binding in rat brains
- Source :
- Nuclear Medicine and Biology. 39(2):199-206
- Publication Year :
- 2012
-
Abstract
- Introduction We recently developed a selective 11 C-labeled I 2 -imidazoline receptor (I 2 R) ligand, 2-(3-fluoro-4-[ 11 C]tolyl)-4,5-dihydro-1 H -imidazole ([ 11 C]FTIMD). [ 11 C]FTIMD showed specific binding to I 2 Rs in rat brains having a high density of I 2 R, as well as to I 2 Rs those in monkey brains, as illustrated by positron emission tomography (PET) and autoradiography. However, [ 11 C]FTIMD also showed moderate non-specific binding in rat brains. In order to increase the specificity for I 2 R in rat brains, we synthesized [ 11 C]FTIMD with ultra-high specific activity and evaluated its binding. Methods [ 11 C]FTIMD with ultra-high specific activity was prepared by a palladium-promoted cross-coupling reaction of the tributylstannyl precursor and [ 11 C]methyl iodide, which was produced by iodination of [ 11 C]methane using the single-pass method. Dynamic PET scans were conducted in rats, and the kinetic parameters were estimated. Results [ 11 C]FTIMD with ultra-high specific activity was successfully synthesized with an appropriate level of radioactivity and ultra-high specific activity (4470±1660 GBq/μmol at end of synthesis, n =11) for injection. In the PET study, distribution volume ( V T ) values in all the brain regions investigated whether I 2 R expression was greatly reduced in BU224-pretreatead rats compared with control rats (29–45% decrease). Differences in V T values between control and BU224-pretreated rats using [ 11 C]FTIMD with ultra-high specific activity were greater than those using [ 11 C]FTIMD with normal specific activity (17–34% decrease) in all brain regions investigated. Conclusion Quantitative PET using [ 11 C]FTIMD with ultra-high specific activity can contribute to the detection of small changes in I 2 R expression in the brain.
- Subjects :
- Male
Cancer Research
Stereochemistry
Central nervous system
chemistry.chemical_element
Imidazoline receptor
Iodine
Rats, Sprague-Dawley
chemistry.chemical_compound
medicine
Imidazole
Animals
Radiology, Nuclear Medicine and imaging
Tissue Distribution
Receptor
Chemistry
Ligand
Imidazoles
Brain
Rats
medicine.anatomical_structure
Biochemistry
Positron-Emission Tomography
Molecular Medicine
Specific activity
Imidazoline Receptors
Methyl iodide
Protein Binding
Subjects
Details
- Language :
- English
- ISSN :
- 09698051
- Volume :
- 39
- Issue :
- 2
- Database :
- OpenAIRE
- Journal :
- Nuclear Medicine and Biology
- Accession number :
- edsair.doi.dedup.....cdce4225ea0722bf84809826f0240648