Up‐regulation of NMDA receptor subunit and post‐synaptic density protein expression in the thalamus of elderly patients with schizophrenia

• Published in: Journal of neurochemistry Vol. 98; no. 4; pp. 1114 - 1125
• Main Authors: Clinton, Sarah M., Haroutunian, Vahram, Meador‐Woodruff, James H.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.08.2006; Blackwell
• Subjects: Aged; Aged, 80 and over; Aminoacid receptors (glycine, glutamate, gaba); Biological and medical sciences; Blotting, Western; Cell receptors; Cell structures and functions; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Female; Fundamental and applied biological sciences. Psychology; Gene expression; glutamate; Humans; Image Processing, Computer-Assisted; In Situ Hybridization; Male; Medical sciences; mediodorsal nucleus; Middle Aged; Molecular and cellular biology; Nerve Tissue Proteins - biosynthesis; Neurology; Neurosciences; NMDA receptor subunit 2B; Older people; post‐synaptic density protein 95; Proteins; Receptors, N-Methyl-D-Aspartate - biosynthesis; Schizophrenia; Schizophrenia - metabolism; Synapses - metabolism; Thalamus - metabolism; Tubulin - biosynthesis; Up-Regulation - genetics; Up-Regulation - physiology; Human; NMDA receptor subunit 2B; Lateral nucleus; Central nervous system; Alteration; Schizophrenia; Glutamate receptor; Binding site; Glutamate; Protein; Encephalon; Psychosis; mediodorsal nucleus; Ventral nucleus; post-synaptic density protein 95; Excitatory aminoacid; Neurotransmitter; Thalamus; Intracellular; NMDA receptor; Elderly; Neurotransmission
• ISSN: 0022-3042; 1471-4159
• DOI: 10.1111/j.1471-4159.2006.03954.x

Numerous studies have described structural and functional abnormalities of the thalamus in schizophrenia, but surprisingly few studies have examined neurochemical abnormalities that accompany these pathological changes. We previously identified abnormalities of multiple molecules associated with glutamatergic neurotransmission, including changes in NMDA receptor subunit transcripts and binding sites and NMDA receptor‐associated post‐synaptic density (PSD) protein transcripts in the thalamus of elderly patients with schizophrenia. In the present study, we performed western blot analysis to determine whether protein levels of NMDA receptor subunits (NR1, NR2A, NR2B) and associated PSD proteins (NF‐L, PSD95, SAP102) are altered in schizophrenia. Thalamic tissue from each subject was grossly dissected into two regions: a dorsomedial region containing limbic‐associated dorsomedial, anterior and central medial thalamic nuclei; and a ventral thalamus region that primarily consisted of the ventral lateral nucleus. We observed increased protein expression of the NR2B NMDA receptor subunit and its associated intracellular protein, PSD95, in the dorsomedial thalamus of patients with schizophrenia, but the other molecules were unchanged, and we found no changes in the ventral thalamus. These data provide additional evidence of thalamic neurochemical abnormalities, particularly in thalamic nuclei which project to limbic regions of the brain. Further, these findings provide additional evidence of NMDA receptor alterations in schizophrenia, which may play an important role in the neurobiology of the illness.