Psychopharmacology

, Volume 190, Issue 3, pp 373–382

Interaction of the novel antipsychotic aripiprazole with 5-HT1A and 5-HT2A receptors: functional receptor-binding and in vivo electrophysiological studies

  • Arlene D. Stark
  • Shaun Jordan
  • Kelly A. Allers
  • Robert L. Bertekap
  • Ruoyan Chen
  • Tanaz Mistry Kannan
  • Thaddeus F. Molski
  • Frank D. Yocca
  • Trevor Sharp
  • Tetsuro Kikuchi
  • Kevin D. Burris
Original Investigation

DOI: 10.1007/s00213-006-0621-y

Cite this article as:
Stark, A.D., Jordan, S., Allers, K.A. et al. Psychopharmacology (2007) 190: 373. doi:10.1007/s00213-006-0621-y

Abstract

Background

Aripiprazole (7-{4-[4-(2,3-dichlorophenyl)-1-piperazinyl]butoxy}-3,4-dihydro-2(1H)-quinolinone) is a novel antipsychotic with a mechanism of action that differs from current typical and atypical antipsychotics. Aripiprazole interacts with a range of receptors, including serotonin [5-hydroxytryptamine (5-HT)] and dopamine receptors.

Materials and methods

This study examined aripiprazole’s interactions with 5-HT systems in vitro and in vivo to further clarify its pharmacologic properties.

Results

Aripiprazole produced increases in [35S]GTPγS binding to rat hippocampal membranes. Its potency (pEC50 = 7.2) was similar to that of ziprasidone (7.1) and greater than that of 5-HT (6.7) and buspirone (6.4), a 5-HT1A-receptor partial agonist, whereas its intrinsic activity was similar to that of ziprasidone and buspirone. The stimulatory effect of aripiprazole was blocked by WAY-100635, a 5-HT1A-receptor antagonist. In in vivo electrophysiology studies, aripiprazole produced a dose-related reduction in the firing rate of 5-HT-containing dorsal raphe neurons in rats, which was both prevented and reversed by WAY-100635 administration. Aripiprazole showed a high affinity for human 5-HT1A receptors (Ki = 4.2 nM) using parietal cortex membrane preparations. In membranes from cells expressing human recombinant receptors, aripiprazole bound with high affinity to 5-HT2A receptors (Ki = 3.4 nM), moderate affinity to 5-HT2C (Ki = 15 nM) and 5-HT7 (Ki = 39 nM) receptors, and low affinity to 5-HT6 receptors (Ki = 214 nM) and 5-HT transporter (Ki = 98 nM). In addition, aripiprazole potently blocked 5-HT2A-receptor-mediated increases in intracellular Ca2+ levels in a rat pituitary cell line (IC50 = 11 nM).

Discussion

These results support a partial agonist activity for aripiprazole at 5-HT1A receptors in vitro and in vivo, and suggest important interactions with other 5-HT-receptor subtypes. This receptor activity profile may contribute to the antipsychotic activity of aripiprazole in humans.

Keywords

AripiprazoleDopamineSerotoninSchizophreniaPartial agonistAntagonist

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Arlene D. Stark
    • 1
  • Shaun Jordan
    • 2
  • Kelly A. Allers
    • 3
  • Robert L. Bertekap
    • 1
  • Ruoyan Chen
    • 2
  • Tanaz Mistry Kannan
    • 1
  • Thaddeus F. Molski
    • 1
  • Frank D. Yocca
    • 1
  • Trevor Sharp
    • 3
  • Tetsuro Kikuchi
    • 4
  • Kevin D. Burris
    • 5
  1. 1.Neuroscience Drug DiscoveryBristol-Myers Squibb Pharmaceutical Research InstituteWallingfordUSA
  2. 2.Otsuka Maryland Research Institute, Inc.RockvilleUSA
  3. 3.Department of PharmacologyOxford UniversityOxfordUK
  4. 4.Otsuka Pharmaceutical Co. Ltd.TokushimaJapan
  5. 5.Palatin TechnologiesCranburyUSA