title: Initial in vivo PET imaging of 5-HT1A receptors with 3-[(18)F]mefway.
abstract: 4-trans-[(18)F]Mefway is a PET radiotracer with high affinity for 5-HT1A receptors. Our preliminary work indicated the positional isomer, 3-[(18)F]mefway, would be suitable for PET imaging of 5-HT1A receptors. We now compare the in vivo behaviour of 3-mefway with 4-mefway to evaluate 3-[(18)F]mefway as a potential 5-HT1A PET radiotracer. Two male rhesus macaques were given bolus injections of both 3- and 4-trans-[(18)F]mefway in separate experiments. 90 minute dynamic PET scans were acquired. TACs were extracted in the mesial temporal lobe (MTL) and caudal anterior cingulate gyrus (cACg). The cerebellum (CB) was used as a reference region. In vivo behavior of the radiotracers in the CB was compared based upon the ratio of normalized PET uptake for 3- and 4-trans-[(18)F]mefway. Specific binding was compared by examining MTL/CB and cACg/CB ratios. The subject-averaged ratio of 3-[(18)F]mefway to 4-trans-[(18)F]mefway in the cerebellum was 0.96 for 60-90 minutes. MTL/CB reached plateaus of ~2.7 and ~6 by 40 minutes and 90 minutes for 3- and 4-trans-[(18)F]mefway, respectively. cACg/CB reached plateaus of ~2.5 and ~6 by 40 minutes and 70 minutes for 3- and 4-trans-[(18)F]mefway, respectively. The short pseudoequilibration times and sufficient uptake of 3-[(18)F]mefway may be useful in studies requiring short scan times. Furthermore, the similar nondisplaceable clearance in the CB to 4-trans-[(18)F]mefway suggests the lower BPND of 3-[(18)F]mefway is due to a lower affinity. The lower affinity of 3-[(18)F]mefway may make it useful for measuring changes in endogenous 5-HT levels, however, this remains to be ascertained.
authors.affiliation: Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin-Madison Madison, WI 53705 ; Department of Medical Physics, University of Wisconsin-Madison Madison, WI 53705 ; Center for Advanced Medical Imaging Sciences, Massachusetts General Hospital, Harvard Medical School Boston, MA 02114.
authors.forename: Dustin W
authors.initials: DW
authors.lastname: Wooten
authors.affiliation: Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin-Madison Madison, WI 53705 ; Department of Medical Physics, University of Wisconsin-Madison Madison, WI 53705.
authors.forename: Ansel T
authors.initials: AT
authors.lastname: Hillmer
authors.affiliation: Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin-Madison Madison, WI 53705 ; Department of Medical Physics, University of Wisconsin-Madison Madison, WI 53705.
authors.forename: Dhanabalan
authors.initials: D
authors.lastname: Murali
authors.affiliation: Department of Medical Physics, University of Wisconsin-Madison Madison, WI 53705.
authors.forename: Todd E
authors.initials: TE
authors.lastname: Barnhart
authors.affiliation: Department of Radiological Sciences, University of California-Irvine Irvine, CA 92697.
authors.forename: Joanne P
authors.initials: JP
authors.lastname: Thio
authors.affiliation: Department of Radiological Sciences, University of California-Irvine Irvine, CA 92697.
authors.forename: Alisha K
authors.initials: AK
authors.lastname: Bajwa
authors.affiliation: Center for Advanced Medical Imaging Sciences, Massachusetts General Hospital, Harvard Medical School Boston, MA 02114.
authors.forename: Ali A
authors.initials: AA
authors.lastname: Bonab
authors.affiliation: Center for Advanced Medical Imaging Sciences, Massachusetts General Hospital, Harvard Medical School Boston, MA 02114.
authors.forename: Marc D
authors.initials: MD
authors.lastname: Normandin
authors.affiliation: Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin-Madison Madison, WI 53705 ; Harlow Center for Biological Psychology, University of Wisconsin Madison ; Department of Kinesiology, University of Wisconsin Madison.
authors.forename: Mary L
authors.initials: ML
authors.lastname: Schneider
authors.affiliation: Department of Radiological Sciences, University of California-Irvine Irvine, CA 92697.
authors.forename: Jogeshwar
authors.initials: J
authors.lastname: Mukherjee
authors.affiliation: Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin-Madison Madison, WI 53705 ; Department of Medical Physics, University of Wisconsin-Madison Madison, WI 53705 ; Department of Psychiatry, University of Wisconsin Madison.
authors.forename: Bradley T
authors.initials: BT
authors.lastname: Christian
keywords: 5-HT1A; PET; mefway; serotonin