Cognitive enhancement effects of Bacopa monnieri (Brahmi) on novel object recognition and NMDA receptor immunodensity in the prefrontal cortex and hippocampus of sub-chronic phencyclidine rat model of schizophrenia

J Med Assoc Thai. 2013 Feb;96(2):231-8.


Background: Cognitive impairment is a common characteristic in schizophrenia that cannot be attenuated by antipsychotics. Brahmi, popularly known as a cognitive enhancer might be a new frontier of cognitive deficit treatment in schizophrenia.

Objective: To study effects of Brahmi on attenuation at cognitive deficit and cerebral glutamate/N-methyl-D-aspartate (NMDA) receptor density in sub-chronic phencyclidine (PCP) rat model of schizophrenia.

Material and method: Rats were administered PCP or vehicle. Half of the PCP-group was treated with Brahmi. Discrimination ratio (DR) representing cognitive ability was obtained from novel object recognition task. NMDA immunodensity was measured in prefrontal cortex, striatum, cornu ammonis fields 1 to 3 of hippocampus (CA1-3), and dentate gyrus (DG) using immunohistochemistry.

Results: DR in PCP-group was significantly decreased compared with control. This occurred alongside NMDA up-regulation in prefrontal cortex and CA1-3, but not in striatum and DG. PCP with Brahmi showed a significant increase in DR score compared with PCP alone. This occurred alongside significant decrease in NMDA immunodensity in prefrontal cortex and CA1-3. No significant difference in cerebral NMDA immunodensity was observed between PCP with Brahmi and control.

Conclusion: Cognitive deficit observed in PCP-administered rats was mediated by NMDA up-regulation in prefrontal cortex and CA1-3. Interestingly, Brahmi could recover this cognitive deficit by decreasing NMDA density in these brain areas to normal.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacopa*
  • Cognition Disorders / drug therapy*
  • Cognition*
  • Disease Models, Animal
  • Hallucinogens / adverse effects
  • Hippocampus / metabolism
  • Image Processing, Computer-Assisted
  • Immunohistochemistry
  • Male
  • Nootropic Agents / pharmacology*
  • Phencyclidine / adverse effects
  • Phytotherapy*
  • Prefrontal Cortex / metabolism
  • Rats
  • Rats, Wistar
  • Receptors, N-Methyl-D-Aspartate
  • Schizophrenia / chemically induced


  • Hallucinogens
  • Nootropic Agents
  • Receptors, N-Methyl-D-Aspartate
  • Phencyclidine