Normal cellular levels of synaptophysin mRNA expression in the prefrontal cortex of subjects with schizophrenia

Background: Previous studies have reported that the 38-kd synaptic vesicle- associated protein, synaptophysin, is decreased in the prefrontal cortex of subjects with schizophrenia. Methods: To determine whether the decreased protein levels reflect diminish ed expression of the synaptophysin gene by prefrontal cortex neurons, we us ed in situ hybridization histochemistry to determine the cellular levels of synaptophysin messenger RNA in prefrontal cortex area 9 from 10 matched pa irs of schizophrenic and normal control subjects. Results: Neither the density of neurons with detectable levels of synaptoph ysin messenger RNA nor the mean level of synaptophysin messenger RNA expres sion per neuron differed between schizophrenic and control subjects in any cortical layer Conclusions: These findings indicate that the expression of synaptophysin m essenger RNA is not altered in this brain region in schizophrenia, Conseque ntly, reduced levels of synaptophysin protein in the prefrontal cortex of s ubjects with schizophrenia are more likely to reflect either posttranscript ional abnormalities of synaptophysin in prefrontal cortex neurons or a dimi nished number of axonal projections to the prefrontal cortex from other bra in regions. (C) 2000 Society of Biological Psychiatry.