Effects of long-term treatment with the neuroleptics haloperidol, clozapine and olanzapine on immunoexpression of NMDA receptor subunits NR1, NR2A and NR2B in the rat hippocampus

Pharmacol Rep. 2015 Oct;67(5):965-9. doi: 10.1016/j.pharep.2015.01.017. Epub 2015 Feb 14.

Abstract

Background: Antagonists of the N-methyl-d-aspartate receptor (NMDA-R) are associated with symptoms of schizophrenia, leading to the hypothesis that NMDA-R hypofunction leads to the pathogenesis of disease. We evaluated the long-term effect of neuroleptic administration on the NMDA subunits via immunohistochemical analysis.

Methods: Rats received olanzapine, clozapine and haloperidol before evaluation of the expression of the NR1, NR2A and NR2B subunit proteins in the hippocampal areas of the brain, via a densytometric analysis of immunoexpression in the rat hippocampus.

Results: All of the neuroleptics examined caused a decrease in the expression of the NR1 subunit, and thus, one can assume that both olanzapine, clozapine and haloperidol decreased the number of NMDA receptors in the CA1 and CA2 areas of the brain.

Conclusions: A decrease in hippocampal glutamatergic signalling after long-term neuroleptic administration may cautiously explain the incomplete effectiveness of these drugs in the therapy of schizophrenia-related cognitive disturbances.

Keywords: Glutamate; Hippocampus; NMDA receptor; Neuroleptics.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antipsychotic Agents / pharmacology*
  • Benzodiazepines / pharmacology*
  • CA1 Region, Hippocampal / drug effects
  • CA1 Region, Hippocampal / metabolism
  • CA2 Region, Hippocampal / drug effects
  • CA2 Region, Hippocampal / metabolism
  • CA3 Region, Hippocampal / drug effects
  • CA3 Region, Hippocampal / metabolism
  • Clozapine / pharmacology*
  • Dentate Gyrus / drug effects
  • Dentate Gyrus / metabolism
  • Haloperidol / pharmacology*
  • Hippocampus / drug effects*
  • Male
  • Olanzapine
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, N-Methyl-D-Aspartate / antagonists & inhibitors*
  • Signal Transduction / drug effects

Substances

  • Antipsychotic Agents
  • NR1A NMDA receptor, rat
  • NR2A NMDA receptor
  • NR2B NMDA receptor
  • Receptors, N-Methyl-D-Aspartate
  • Benzodiazepines
  • Clozapine
  • Haloperidol
  • Olanzapine