Alzheimer's Disease Research Today is a free monthly online journal that collates and summarizes the latest research about Alzheimer's Disease, including details on diagnosis, memory loss, heredity, treatment, medication.

Synapse formation and function is modulated by the amyloid precursor protein.

Priller C, Bauer T, Mitteregger G, Krebs B, Kretzschmar HA, Herms J

Zentrum für Neuropathologie und Prion Forschung, Ludwig Maximilians Universität, 81377 Munich, Germany.

The amyloid precursor protein (APP) is critical in the pathogenesis of Alzheimer's disease. The question of its normal biological function in neurons, in which it is predominantly located at synapses, is still unclear. Using autaptic cultures of hippocampal neurons, we demonstrate that hippocampal neurons lacking APP show significantly enhanced amplitudes of evoked AMPA- and NMDA-receptor-mediated EPSCs. The size of the readily releasable synaptic vesicle pool was also increased in neurons lacking APP, whereas the release probability was not affected. In addition, the analysis of spontaneous miniature synaptic currents revealed an augmented frequency in neurons lacking APP, whereas the amplitude of miniature synaptic currents was not found to be altered. Together, these findings strongly indicate that lack of APP increases the number of functional synapses. This hypothesis is further supported by morphometric immunohistochemical analysis revealing an increase of synaptophysin-positive puncta per cultured APP knock-out neuron. In conclusion, lack of APP affects synapse formation and transmission in cultured hippocampal neurons.

Published 6 July 2006 in J Neurosci, 26(27): 7212-21.
Full-text of this article is available online (may require subscription).

© 2004-2008 Alzheimer's Disease Research Today. All Rights Reserved.