Receptor mechanisms and circuitry underlying NMDA antagonist neurotoxicity

N. B. Farber, Seung Hyun Kim, K. Dikranian, X. P. Jiang, C. Heinkel

Research output: Contribution to journalArticle

103 Citations (Scopus)

Abstract

NMDA glutamate receptor antagonists are used in clinical anesthesia, and are being developed as therapeutic agents for preventing neurodegeneration in stroke, epilepsy, and brain trauma. However, the ability of these agents to produce neurotoxicity in adult rats and psychosis in adult humans compromises their clinical usefulness. In addition, an NMDA receptor hypofunction (NRHypo) state might play a role in neurodegenerative and psychotic disorders, like Alzheimer's disease and schizophrenia. Thus, understanding the mechanism underlying NRHypo-induced neurotoxicity and psychosis could have significant clinically relevant benefits. NRHypo neurotoxicity can be prevented by several classes of agents (eg antimuscarinics, non-NMDA glutamate antagonists, and α2 adrenergic agonists) suggesting that the mechanism of neurotoxicity is complex. In the present study a series of experiments was undertaken to more definitively define the receptors and complex neural circuitry underlying NRHypo neurotoxicity. Injection of either the muscarinic antagonist scopolamine or the non-NMDA antagonist NBQX directly into the cortex prevented NRHypo neurotoxicity. Clonidine, an α2 adrenergic agonist, protected against the neurotoxicity when injected into the basal forebrain. The combined injection of muscarinic and non-NMDA Glu agonists reproduced the neurotoxic reaction. Based on these and other results, we conclude that the mechanism is indirect, and involves a complex network disturbance, whereby blockade of NMDA receptors on inhibitory neurons in multiple subcortical brain regions, disinhibits glutamatergic and cholinergic projections to the cerebral cortex. Simultaneous excitotoxic stimulation of muscarinic (m3) and glutamate (AMPA/kainate) receptors on cerebrocortical neurons appears to be the proximal mechanism by which the neurotoxic and psychotomimetic effects of NRHypo are mediated.

Original languageEnglish
Pages (from-to)32-43
Number of pages12
JournalMolecular Psychiatry
Volume7
Issue number1
DOIs
Publication statusPublished - 2002 Jan 1

Fingerprint

N-Methylaspartate
N-Methyl-D-Aspartate Receptors
Psychotic Disorders
Cholinergic Agents
Excitatory Amino Acid Antagonists
Adrenergic Agonists
Muscarinic Antagonists
Kainic Acid Receptors
Neurons
Injections
Aptitude
Scopolamine Hydrobromide
AMPA Receptors
Clonidine
Sensory Receptor Cells
Neurodegenerative Diseases
Cerebral Cortex
Glutamic Acid
Epilepsy
Schizophrenia

Keywords

  • Alzheimer’s disease
  • Dissociative anesthetics
  • Mk801
  • Neurodegeneration
  • Psychosis
  • Rats
  • Retrosplenial cortex
  • Rodents
  • Schizophrenia

ASJC Scopus subject areas

  • Molecular Biology
  • Psychiatry and Mental health
  • Cellular and Molecular Neuroscience

Cite this

Receptor mechanisms and circuitry underlying NMDA antagonist neurotoxicity. / Farber, N. B.; Kim, Seung Hyun; Dikranian, K.; Jiang, X. P.; Heinkel, C.

In: Molecular Psychiatry, Vol. 7, No. 1, 01.01.2002, p. 32-43.

Research output: Contribution to journalArticle

Farber, N. B. ; Kim, Seung Hyun ; Dikranian, K. ; Jiang, X. P. ; Heinkel, C. / Receptor mechanisms and circuitry underlying NMDA antagonist neurotoxicity. In: Molecular Psychiatry. 2002 ; Vol. 7, No. 1. pp. 32-43.
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