Non-competitive antagonists of the glutamate N-methyl-D-aspartate receptor (NMDAR) induce a broad range of schizophrenia-like symptoms in humans. Consequently hypothesis has emerged suggesting that glutamate or NMDAR hypofunction may occur in schizophrenia. The NMDAR is localised at dendritic spines of neurons and is embedded in a multi-protein complex called the post-synaptic density (PSD). The biochemical composition of the postsynaptic membrane and the structure of dendritic spines are continuously modulated by glutamatergic synaptic activity. The activity-dependent interaction between glutamate receptors and proteins of the PSD stimulate intracellular signalling pathways underlying learning and memory processes. These may be disturbed in schizophrenia. In the present study we hypothesised that molecules of the PSD may be disturbed in expression in the premotor cortex of patients with schizophrenia. Postmortem premotor cortex from patients with schizophrenia, major depressive disorder, bipolar disorder and healthy controls were processed for PSD extraction and purification. Protein expression of the PSD fraction was assessed using co-immunoprecipitation (co-IP) and Western blotting (WB) methods. The expression of NMDAR subunit NR2A, PSD-95, Ca2+/calmodulin-dependent protein kinase II subunit β (CaMKIIβ) and truncated isoform of the tropomyosin receptor kinase type B (TrkB-T1) were significantly reduced in schizophrenia. A significant decrease in the expression of NR2A was also observed in patients with major depressive disorder relative to controls. A decrease in the abundance of key PSD proteins in schizophrenia provides strong evidence that PSD function and possibly synaptic plasticity may be disturbed in the premotor cortex in the disease. There may also be more subtle disturbances in PSD function in major depressive disorder.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:575733 |
| Date | January 2012 |
| Creators | Matas, Emmanuel |
| Contributors | Toro, Carla |
| Publisher | Cranfield University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://dspace.lib.cranfield.ac.uk/handle/1826/7999 |
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