Synthesis, radiosynthesis, and biological evaluation of fluorine-18-labeled 2beta-carbo(fluoroalkoxy)-3beta-(3'-((Z)-2-haloethenyl)phenyl)nortropanes: candidate radioligands for in vivo imaging of the serotonin transporter with positron emission tomography

J Med Chem. 2008 Dec 25;51(24):7788-99. doi: 10.1021/jm800781a.

Abstract

The meta-vinylhalide fluoroalkyl ester nortropanes 1-4 were synthesized as ligands of the serotonin transporter (SERT) for use as positron emission tomography (PET) imaging agents. In vitro competition binding assays demonstrated that 1-4 have a high affinity for the SERT (K(i) values = 0.3-0.4 nM) and are selective for the SERT over the dopamine and norepinephrine transporters (DAT and NET). MicroPET imaging in anesthetized cynomolgus monkeys with [(18)F]1-[(18)F]4 demonstrated that all four tracers behave similarly with peak uptake in the SERT-rich brain regions achieved after 45-55 min, followed by a steady washout. An awake monkey study was performed with [(18)F]1, which demonstrated that the uptake of [(18)F]1 was not influenced by anesthesia. Chase studies with the SERT ligand 15 displaced [(18)F]1-[(18)F]4, but chase studies with the DAT ligand 16 did not displace [(18)F]1-[(18)F]4 thus indicating that the tracers were binding specifically to the SERT.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Drug Design
  • Fluorine Radioisotopes / chemistry*
  • Humans
  • Kinetics
  • Ligands
  • Macaca mulatta
  • Models, Chemical
  • Neurotransmitter Agents / chemistry
  • Norepinephrine Plasma Membrane Transport Proteins / metabolism
  • Nortropanes / chemical synthesis*
  • Nortropanes / chemistry*
  • Positron-Emission Tomography / instrumentation
  • Positron-Emission Tomography / methods*
  • Radiopharmaceuticals / chemistry
  • Serotonin Plasma Membrane Transport Proteins / chemistry*
  • Time Factors

Substances

  • Fluorine Radioisotopes
  • Ligands
  • Neurotransmitter Agents
  • Norepinephrine Plasma Membrane Transport Proteins
  • Nortropanes
  • Radiopharmaceuticals
  • Serotonin Plasma Membrane Transport Proteins