Increased levels of expression of an NMDARI splice variant in the superior temporal gyrus in schizophrenia.

Expression patterns of mRNAs for the NMDARI subunit (NRI) carboxy-terminus isoforms were investigated in postmortem brain tissue using isotopic in situ hybridization. Three brain regions (superior temporal, middle frontal and visual cortices) were examined in patients with schizophrenia (n = 6) and control subjects (n = 6). A 22% higher level of expression of the NRI isoform that contains neither spliced exon was observed in the superior temporal gyrus of patients with schizophrenia compared with controls (p = 0.01). No differences were observed in the expression of the other isoforms in the three regions studied. These data suggest that NRI alternative splicing might be abnormal in schizophrenia and reinforce previous findings implicating the superior temporal gyrus as a site of neural dysfunction in schizophrenia.