[18F]CFT ([18F]WIN 35,428), a radioligand to study the dopamine transporter with PET: biodistribution in rats

Synapse. 1996 Aug;23(4):321-7. doi: 10.1002/(SICI)1098-2396(199608)23:4<321::AID-SYN10>3.0.CO;2-#.

Abstract

We describe the 18F-radiolabelling synthesis (18F; T(1/2) = 109.8 min) of 2-beta-carbomethoxy-3 beta-(4-fluorophenyl)tropane (also known as CFT or WIN 35,428) and the biodistribution of this compound in rats. 18F-labelled CFT has high chemical and radiochemical purity and relatively high specific radioactivity [specific radioactivity up to 14.8 GBq/mumol (400 mCi/mumol) at end of synthesis]. Striatum to cerebellum radioactivity uptake ratios were calculated from digitised images of rat brain slices recorded with a phosphoimaging device, the maximum ratio of about 10 was obtained at 2 h postinjection. Pretreatment of the rats with a specific dopamine transport inhibitor, GBR 12909, showed that CFT binding is specific in striatum. The highest accumulation of 18F-radioactivity was found in the liver, urine, striatum, and kidney of the rat. Clearance from blood was rapid. The uptake in bone was low, indicating that [18F]CFT is not defluorinated. The relatively long half-life of 18F makes it possible to study the uptake of [18F]CFT in the brain, as equilibrium between specific and non-specific binding is reached. This will improve the signal to noise ratio as compared to positron emission tomography (PET) studies with [11C]CFT (11C; T(1/2) = 20.4 min). CFT labelled with 18F is clearly a promising radioligand for PET studies of the dopamine transporter system in humans.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain / diagnostic imaging
  • Brain / metabolism*
  • Carrier Proteins / metabolism*
  • Cocaine / analogs & derivatives*
  • Cocaine / metabolism
  • Cocaine / pharmacokinetics
  • Dopamine Plasma Membrane Transport Proteins
  • Dopamine Uptake Inhibitors / metabolism*
  • Dopamine Uptake Inhibitors / pharmacokinetics
  • Fluorine Radioisotopes
  • Male
  • Membrane Glycoproteins*
  • Membrane Transport Proteins*
  • Nerve Tissue Proteins*
  • Radioligand Assay
  • Rats
  • Rats, Sprague-Dawley
  • Tissue Distribution
  • Tomography, Emission-Computed

Substances

  • Carrier Proteins
  • Dopamine Plasma Membrane Transport Proteins
  • Dopamine Uptake Inhibitors
  • Fluorine Radioisotopes
  • Membrane Glycoproteins
  • Membrane Transport Proteins
  • Nerve Tissue Proteins
  • (1R-(exo,exo))-3-(4-fluorophenyl)-8-methyl-8- azabicyclo(3.2.1)octane-2-carboxylic acid, methyl ester
  • Cocaine