Preserved synaptic vesicle recycling in hippocampal neurons in a mouse Alzheimer's disease model

A recently described triple-transgenic mouse model (3×Tg, PS1M146V, APPSwe, and tauP301L) develops a neuropathology similar to the brains of Alzheimer's disease patients including progressive deposits of plaques and tangles [Neuron 39 (2003) 409]. These mice also show age-related deficits in hippocampal synaptic plasticity that occurs before the development of plaques and tangles. Here we report unchanged synaptic vesicle recycling, as measured by FM1-43 release, in the hippocampal neurons of the 3×Tg mice. Expression levels of presynaptic protein synaptophysin and of proteins involved in synaptic vesicle recycling including AP180, dynamin I, and synaptotagmin I also remain unaffected. These data suggest that the synaptic deficits observed in the 3×Tg neurons may not arise from the preserved synaptic vesicle recycling.