Comparison of [(18)F]altanserin and [(18)F]deuteroaltanserin for PET imaging of serotonin(2A) receptors in baboon brain: pharmacological studies

Nucl Med Biol. 2001 Apr;28(3):271-9. doi: 10.1016/s0969-8051(00)00212-2.


The regional distribution in brain, distribution volumes, and pharmacological specificity of the PET 5-HT(2A) receptor radiotracer [(18)F]deuteroaltanserin were evaluated and compared to those of its non-deuterated derivative [(18)F]altanserin. Both radiotracers were administered to baboons by bolus plus constant infusion and PET images were acquired up to 8 h. The time-activity curves for both tracers stabilized between 4 and 6 h. The ratio of total and free parent to metabolites was not significantly different between radiotracers; nevertheless, total cortical R(T) (equilibrium ratio of specific to nondisplaceable brain uptake) was significantly higher (34-78%) for [(18)F]deuteroaltanserin than for [(18)F]altanserin. In contrast, the binding potential (Bmax/K(D)) was similar between radiotracers. [(18)F]Deuteroaltanserin cortical activity was displaced by the 5-HT(2A) receptor antagonist SR 46349B but was not altered by changes in endogenous 5-HT induced by fenfluramine. These findings suggest that [(18)F]deuteroaltanserin is essentially equivalent to [(18)F]altanserin for 5-HT(2A) receptor imaging in the baboon.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Analysis of Variance
  • Animals
  • Brain / metabolism*
  • Deuterium
  • Female
  • Fluorine Radioisotopes* / metabolism
  • Fluorine Radioisotopes* / pharmacokinetics
  • Ketanserin / analogs & derivatives*
  • Ketanserin / metabolism
  • Ketanserin / pharmacokinetics
  • Papio
  • Radiochemistry
  • Receptors, Serotonin / metabolism*
  • Tomography, Emission-Computed*


  • Fluorine Radioisotopes
  • Receptors, Serotonin
  • altanserin
  • Ketanserin
  • Deuterium