Effects of synaptic modulation on beta-amyloid, synaptophysin, and memory performance in Alzheimer's disease transgenic mice.

ABSTRACT: Accumulation of ?-amyloid (A?) and loss of synapses are hallmarks of Alzheimer's disease (AD). How synaptic activity relates to A? accumulation and loss of synapses is a current topic of major interest. Synaptic activation promotes A? secretion, and chronic reduction of synaptic activity reduced A? plaques in an AD transgenic mouse model. This suggested beneficial effects of reducing synaptic activity in AD. We now show that reduced synaptic activity causes detrimental effects on synapses and memory despite reducing plaques using two different models of chronic synaptic inhibition: deafferentation of the barrel cortex and administration of benzodiazepine. An interval of prolonged synaptic inhibition exacerbated loss of synaptophysin compared with synaptically more active brain in AD transgenic but not wild-type mice. Furthermore, an interval of benzodiazepine treatment, followed by a washout period, exacerbated memory impairment in AD transgenic mice. Exacerbation of synaptic and behavioral abnormalities occurred in the setting of reduced A? plaques but elevated intraneuronal A? immunoreactivity. These data support beneficial effects of synaptic activation on A?-related synaptic and behavioral impairment in AD.

SUBMITTER: Tampellini D 

PROVIDER: S-EPMC2972675 | biostudies-literature | 2010 Oct

REPOSITORIES: biostudies-literature