Synthesis and evaluation of a set of 4-phenylpiperidines and 4-phenylpiperazines as D2 receptor ligands and the discovery of the dopaminergic stabilizer 4-[3-(methylsulfonyl)phenyl]-1-propylpiperidine (huntexil, pridopidine, ACR16)

J Med Chem. 2010 Mar 25;53(6):2510-20. doi: 10.1021/jm901689v.


Modification of the partial dopamine type 2 receptor (D(2)) agonist 3-(1-benzylpiperidin-4-yl)phenol (9a) generated a series of novel functional D(2) antagonists with fast-off kinetic properties. A representative of this series, pridopidine (4-[3-(methylsulfonyl)phenyl]-1-propylpiperidine; ACR16, 12b), bound competitively with low affinity to D(2) in vitro, without displaying properties essential for interaction with D(2) in the inactive state, thereby allowing receptors to rapidly regain responsiveness. In vivo, neurochemical effects of 12b were similar to those of D(2) antagonists, and in a model of locomotor hyperactivity, 12b dose-dependently reduced activity. In contrast to classic D(2) antagonists, 12b increased spontaneous locomotor activity in partly habituated animals. The "agonist-like" kinetic profile of 12b, combined with its lack of intrinsic activity, induces a functional state-dependent D(2) antagonism that can vary with local, real-time dopamine concentration fluctuations around distinct receptor populations. These properties may contribute to its unique "dopaminergic stabilizer" characteristics, differentiating 12b from D(2) antagonists and partial D(2) agonists.

MeSH terms

  • 3,4-Dihydroxyphenylacetic Acid / metabolism
  • Animals
  • Binding, Competitive
  • Cell Line
  • Corpus Striatum / drug effects
  • Corpus Striatum / metabolism
  • Dopamine / metabolism
  • Dopamine / pharmacology
  • Dopamine D2 Receptor Antagonists
  • Dose-Response Relationship, Drug
  • Drug Discovery
  • Drug Evaluation, Preclinical
  • Humans
  • Ligands
  • Male
  • Models, Chemical
  • Molecular Structure
  • Motor Activity / drug effects
  • Piperazines / chemical synthesis
  • Piperazines / metabolism*
  • Piperazines / pharmacology
  • Piperidines / chemical synthesis
  • Piperidines / chemistry
  • Piperidines / metabolism*
  • Piperidines / pharmacology
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Dopamine D2 / agonists
  • Receptors, Dopamine D2 / metabolism*


  • Dopamine D2 Receptor Antagonists
  • Ligands
  • Piperazines
  • Piperidines
  • Receptors, Dopamine D2
  • 3,4-Dihydroxyphenylacetic Acid
  • 4-phenylpiperidine
  • pridopidine
  • phenylpiperazine
  • Dopamine