Reduction of dopamine D2/3 receptor binding in the striatum after a single administration of esketamine, but not R-ketamine: a PET study in conscious monkeys

Eur Arch Psychiatry Clin Neurosci. 2017 Mar;267(2):173-176. doi: 10.1007/s00406-016-0692-7. Epub 2016 Apr 18.

Abstract

R-ketamine appears to be a potent, long-lasting and safer antidepressant, relative to esketamine (S-ketamine), since it might be free of psychotomimetic side effects. Using [11C]raclopride and positron emission tomography (PET), we investigated whether esketamine and R-ketamine can affect dopamine D2/3 receptor binding in the conscious monkey brain. A single infusion of esketamine (0.5 mg/kg), but not R-ketamine (0.5 mg/kg), caused a reduction of binding availability of dopamine D2/3 receptor in the monkey striatum. This study suggests that unlike to R-ketamine, esketamine can cause dopamine release in the striatum, and that its release might be associated with psychotomimetic effects of esketamine.

Keywords: Dopamine D2/3 receptor; Esketamine; Monkey; R-ketamine; Release.

MeSH terms

  • Animals
  • Antidepressive Agents / administration & dosage
  • Antidepressive Agents / pharmacology*
  • Ketamine / administration & dosage
  • Ketamine / pharmacology*
  • Macaca mulatta
  • Male
  • Neostriatum / diagnostic imaging
  • Neostriatum / drug effects*
  • Positron-Emission Tomography / methods*
  • Receptors, Dopamine D2 / metabolism*
  • Receptors, Dopamine D3 / metabolism*

Substances

  • Antidepressive Agents
  • Receptors, Dopamine D2
  • Receptors, Dopamine D3
  • Ketamine