[3H]paroxetine and [3H]citalopram as markers of the human brain 5-HT uptake site: a comparison study

J Neural Transm Gen Sect. 1994;97(1):27-40. doi: 10.1007/BF01277960.


The binding of [3H]paroxetine and [3H]citalopram to the human brain serotonin (5-HT) uptake site has been characterized and compared. Our results reveal that the binding exclusively involved with the 5-HT uptake site is identical for both [3H]ligands. The selective 5-HT uptake inhibitor citalopram displays the highest affinity for this uptake site, as compared with the affinities obtained for desipramine and norzimeldine, which is in accordance with their respective blockage of 5-HT uptake. Similar Bmax values were obtained for both radioligands in the brain regions studied, indicating their binding to the same presynaptic membrane protein. Together these findings suggest that both [3H]paroxetine and [3H]citalopram are good markers of the 5-HT transporter as both bind selectively and with high affinity to the serotonin uptake sites. However, the higher affinity of [3H]paroxetine confirms that this compound is the best radioligand for the 5-HT uptake site available today.

Publication types

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

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Animals
  • Binding, Competitive / drug effects
  • Biomarkers
  • Brain Chemistry / drug effects*
  • Citalopram* / pharmacokinetics
  • Female
  • Humans
  • In Vitro Techniques
  • Male
  • Membranes / drug effects
  • Membranes / metabolism
  • Middle Aged
  • Paroxetine* / pharmacokinetics
  • Rats
  • Receptors, Serotonin / drug effects*


  • Biomarkers
  • Receptors, Serotonin
  • Citalopram
  • Paroxetine