RT Journal Article
SR Electronic
T1 Brain-Derived Neurotrophic Factor Rescues Synaptic Plasticity in a Mouse Model of Fragile X Syndrome
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 10685
OP 10694
DO 10.1523/JNEUROSCI.2624-07.2007
VO 27
IS 40
A1 Julie C. Lauterborn
A1 Christopher S. Rex
A1 Eniko Kramár
A1 Lulu Y. Chen
A1 Vijay Pandyarajan
A1 Gary Lynch
A1 Christine M. Gall
YR 2007
UL http://www.jneurosci.org/content/27/40/10685.abstract
AB Mice lacking expression of the fragile X mental retardation 1 (Fmr1) gene have deficits in types of learning that are dependent on the hippocampus. Here, we report that long-term potentiation (LTP) elicited by threshold levels of theta burst afferent stimulation (TBS) is severely impaired in hippocampal field CA1 of young adult Fmr1 knock-out mice. The deficit was not associated with changes in postsynaptic responses to TBS, NMDA receptor activation, or levels of punctate glutamic acid decarboxylase-65/67 immunoreactivity. TBS-induced actin polymerization within dendritic spines was also normal. The LTP impairment was evident within 5 min of induction and, thus, may not be secondary to defects in activity-initiated protein synthesis. Protein levels for both brain-derived neurotrophic factor (BDNF), a neurotrophin that activates pathways involved in spine cytoskeletal reorganization, and its TrkB receptor were comparable between genotypes. BDNF infusion had no effect on baseline transmission or on postsynaptic responses to theta burst stimulation, but nonetheless fully restored LTP in slices from fragile X mice. These results indicate that the fragile X mutation produces a highly selective impairment to LTP, possibly at a step downstream of actin filament assembly, and suggest a means for overcoming this deficit. The possibility of a pharmacological therapy based on these results is discussed.