Synaptic plasticity deficits in an experimental model of Rett Syndrome: LTP saturation and its pharmacological reversal

Weng, S.-M., McLeod, F., Bailey, M.E.S. and Cobb, S.R. (2011) Synaptic plasticity deficits in an experimental model of Rett Syndrome: LTP saturation and its pharmacological reversal. Neuroscience, 180, pp. 314-321. (doi:10.1016/j.neuroscience.2011.01.061)

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Publisher's URL: http://dx.doi.org/10.1016/j.neuroscience.2011.01.061

Abstract

Rett syndrome (RTT), a disorder caused almost exclusively by mutations in the X-linked gene, MECP2, has a phenotype thought to be primarily of neurological origin. Disruption of Mecp2 in mice results in a prominent RTT-like phenotype. One of the consequences of MeCP2 absence in the brain is altered functional and structural plasticity. We aimed to characterize synaptic effects related to plasticity in the hippocampus further and establish whether plasticity defects are amenable to pharmacological reversal. Using male mice in which Mecp2 expression was prevented by a stop cassette, we assessed synaptic plasticity in area CA1 at different phenotypic stages, scoring the mice weekly for overt RTT-like signs. Strongly symptomatic Mecp2(stoply) mice displayed reduced long-term potentiation (LIP, 40.2 +/- 1.6% of wild-type), post-tetanic potentiation (PIP, 45 +/- 18.8% of wildtype) and paired-pulse facilitation (PPF, 78 +/- 0.1% of wild type) (all P < 0.05), the impairment increasing with symptom severity score. These plasticity impairments were absent in presymptomatic mice. Repeated high frequency stimulation revealed pronounced LTP saturation in symptomatic Mecp2(stoply) mice, suggesting an LIP 'ceiling' effect. Bath application of the weak NMDA receptor blocker memantine (1 mu M) resulted in partial restoration of a short-term plasticity component. These data support that idea that progressive functional synaptic impairment is a key feature in the RTT brain and demonstrate the potential for the pharmacological restoration of plasticity function.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Cobb, Dr Stuart and Bailey, Dr Mark
Authors: Weng, S.-M., McLeod, F., Bailey, M.E.S., and Cobb, S.R.
College/School:College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
College of Medical Veterinary and Life Sciences > School of Life Sciences
Journal Name:Neuroscience
Publisher:Elsevier
ISSN:0306-4522
ISSN (Online):1873-7544
Published Online:04 February 2011
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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
480301Reversibility and mapping of Rett Syndrome-like phenotypes in the mouse brainStuart CobbMedical Research Council (MRC)G0800401/86343Institute of Neuroscience and Psychology