Ribosomal DNA transcription in the dorsal raphe nucleus is increased in residual but not in paranoid schizophrenia.

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Ribosomal DNA transcription in the dorsal raphe nucleus is increased in residual but not in paranoid schizophrenia.

Eur Arch Psychiatry Clin Neurosci. 2015 Mar;265(2):117-26

Authors: Krzyżanowska M, Steiner J, Brisch R, Mawrin C, Busse S, Braun K, Jankowski Z, Bernstein HG, Bogerts B, Gos T

Abstract
The central serotonergic system is implicated in the pathogenesis of schizophrenia, where the imbalance between dopamine, serotonin and glutamate plays a key pathophysiological role. The dorsal raphe nucleus (DRN) is the main source of serotonergic innervation of forebrain limbic structures disturbed in schizophrenia patients. The study was carried out on paraffin-embedded brains from 17 (8 paranoid and 9 residual) schizophrenia patients and 28 matched controls without mental disorders. The transcriptional activity of ribosomal DNA (rDNA) in DRN neurons was evaluated by the AgNOR silver-staining method. An increased rDNA transcriptional activity was found in schizophrenia patients in the cumulative analysis of all DRN subnuclei (t test, P = 0.02). Further subgroup analysis revealed that it was an effect specific for residual schizophrenia versus paranoid schizophrenia or control groups (ANOVA, P = 0.002). This effect was confounded neither by suicide nor by antipsychotic medication. Our findings suggest that increased activity of rDNA in DRN neurons is a distinct phenomenon in schizophrenia, particularly in residual patients. An activation of the rDNA transcription in DRN neurons may represent a compensatory mechanism to overcome the previously described prefrontal serotonergic hypofunction in this diagnostic subgroup.

PMID: 25091423 [PubMed - indexed for MEDLINE]