A GABAergic cortical deficit dominates schizophrenia pathophysiology

E. Costa, J. M. Davis, E. Dong, D. R. Grayson, A. Guidotti, L. Tremolizzo, M. Veldic

Research output: Contribution to journalReview articlepeer-review

108 Scopus citations


Several lines of evidence support the role of an epigenetic-induced GABAergic cortical dysfunction in schizophrenia psychopathology, which is probably dependent on an increase in the expression of DNA-methyltransferase-1 occurring selectively in GABAergic neurons. The key enzyme regulating GABA synthesis, termed glutamic acid decarboxylase 67 (GAD67) and the important neurodevelopmental protein called reelin are coexpressed in GABAergic neurons. Upon release, GABA and reelin bind to postsynaptic receptors located in dendrites, somata, or the axon initial segment of pyramidal neurons. Because GAD67 and reelin are downregulated in schizophrenia, it is suggested that schizophrenics may express GABAergic deficit-related alterations of pyramidal neuron function. A reduction of dendritic spines is a finding reported in the prefrontal cortex of schizophrenia patients. Because dendritic spines are innervated by glutamatergic axon terminals, very probably this reduction of dendritic spine expression is translated into a functional deficit of glutamatergic transmission. Plastic modifications of neuronal circuits are probably dependent on GABAergic transmitter tone, and it is likely that GABAergic dysfunction is at the root of synaptic plasticity deficits in schizophrenia. Thus, a possible avenue for the treatment of schizophrenia would be to address this GABAergic functional deficit using positive allosteric modulators of the action of GABA at GABAA receptors. Benzodiazepines (BZ) such as diazepam are effective in treating positive and negative symptoms of schizophrenia, but because they positively modulate GABAA receptors expressing (α1 subunits, these BZs cause sedation and tolerance. In contrast, imidazenil, a full allosteric modulator of GABA A receptors expressing α5 subunits may reduce psychotic symptomatology without producing sedation. Hence, imidazenil should be appropriately studied as a prospective candidate for a pharmacological intervention in schizophrenia.

Original languageEnglish (US)
Pages (from-to)1-23
Number of pages23
JournalCritical reviews in neurobiology
Issue number1-2
StatePublished - Dec 15 2004


  • Benzodiazepines
  • DNA-methyltransferase 1
  • Dendritic spines
  • Epigenetic
  • GABA
  • GABAergic neurons
  • Glutamate
  • Glutamatergic neurons
  • Imidazenil
  • Phencyclidine
  • Reelin
  • Schizophrenia

ASJC Scopus subject areas

  • Neuroscience(all)
  • Physiology
  • Clinical Neurology
  • Physiology (medical)


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