Article

Molecular mechanisms contributing to dendritic spine alterations in the prefrontal cortex of subjects with schizophrenia

Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15213, USA.
Molecular Psychiatry (Impact Factor: 15.15). 07/2006; 11(6):557-66. DOI: 10.1038/sj.mp.4001792
Source: PubMed

ABSTRACT Postmortem studies have revealed reduced densities of dendritic spines in the dorsal lateral prefrontal cortex (DLPFC) of subjects with schizophrenia. However, the molecular mechanisms that might contribute to these alterations are unknown. Recent studies of the intracellular signals that regulate spine dynamics have identified members of the RhoGTPase family (e.g., Cdc42, Rac1, RhoA) as critical regulators of spine structure. In addition, Duo and drebrin are spine-specific proteins that are critical for spine maintenance and spine formation, respectively. In order to determine whether the mRNA expression levels of Cdc42, Rac1, RhoA, Duo or drebrin are altered in schizophrenia, tissue sections containing DLPFC area 9 from 15 matched pairs of subjects with schizophrenia and control subjects were processed for in situ hybridization. Expression levels of these mRNAs were also correlated with DLPFC spine density in a subset of the same subjects. In order to assess the potential influence of antipsychotic medications on the expression of these mRNAs, similar studies were conducted in monkeys chronically exposed to haloperidol or olanzapine. The expression of each of these mRNAs was lower in the gray matter of the subjects with schizophrenia compared to the control subjects, although only the reductions in Cdc42 and Duo remained significant after corrections for multiple comparisons. In addition, spine density was strongly correlated with the expression levels of both Duo (r=0.73, P=0.007) and Cdc42 (r=0.71, P=0.009) mRNAs. In contrast, the expression levels of Cdc42 and Duo mRNAs were not altered in monkeys chronically exposed to antipsychotic medications. In conclusion, reduced expression of Cdc42 and Duo mRNAs may represent molecular mechanisms that contribute to the decreased density of dendritic spines in the DLPFC of subjects with schizophrenia.

0 Followers
 · 
127 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The GABA transmitter system plays a vital role in modulating synaptic formation and activity during development. The GABAB receptor subtype in particular has been implicated in cell migration, promotion of neuronal differentiation, neurite outgrowth, and synapse formation but it's role in development is not well characterized. In order to investigate the effects of brief alterations in GABAB signaling in development, we administered to rats the GABAB agonist baclofen (2.0 mg/kg) or antagonist phaclofen (0.3 mg/kg) on postnatal days 7, 9, and 12, and evaluated sensorimotor gating in adulthood. We also examined tissue for changes in multiple proteins associated with GABAB receptor function and proteins associated with synapse formation. Our data indicate that early postnatal alterations to GABAB receptor-mediated signaling produced sex differences in sensorimotor gating in adulthood. Additionally, we found differences in GABAB receptor subunits and kalirin protein levels in the brain versus saline treated controls. Our data demonstrate that a subtle alteration in GABAB receptor function in early postnatal life induces changes that persist into adulthood.
    International Journal of Developmental Neuroscience 10/2014; 41. DOI:10.1016/j.ijdevneu.2014.10.001 · 2.92 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Schizophrenia is a neurodevelopmental disorder whose clinical features include impairments in perception, cognition and motivation. These impairments reflect alterations in neuronal circuitry within and across multiple brain regions that are due, at least in part, to deficits in dendritic spines, the site of most excitatory synaptic connections. Dendritic spine alterations have been identified in multiple brain regions in schizophrenia, but are best characterized in layer 3 of the neocortex, where pyramidal cell spine density is lower. These spine deficits appear to arise during development, and thus are likely the result of disturbances in the molecular mechanisms that underlie spine formation, pruning, and/or maintenance. Each of these mechanisms may provide insight into novel therapeutic targets for preventing or repairing the alterations in neural circuitry that mediate the debilitating symptoms of schizophrenia. This article is part of a Special Issue entitled: Spine Plasticity and Pathology in Brain Disorders.
    Neuroscience 04/2012; DOI:10.1016/j.neuroscience.2012.04.044 · 3.33 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Dendrite morphogenesis is a complex but well-orchestrated process and includes the development of dendritic branches, forming characteristic dendrite arbors, and dendritic spines, allowing neurons to communicate with each other. Various studies report that many neuropsychiatric disorders are characterized by dendritic and synaptic pathology, including abnormal spine density and morphology, synapse loss, and aberrant synaptic signaling and plasticity. In this review, we discuss dendrite development and branching, and in specific, morphology, cytoskeletal architecture, and how the complexity of the dendrite tree and its functional capabilities are altered in various brain disorders. Identifying and understanding these changes in dendrite morphology are essential for understanding brain function in normal and disease states.
    Molecular and Cellular Neuroscience 03/2012; 50(1):10-20. DOI:10.1016/j.mcn.2012.03.005 · 3.73 Impact Factor

Preview

Download
2 Downloads
Available from