Many recent studies of the effects of amyloid-? protein (A?) on brain tissue from amyloid precursor protein (APP) overexpressing mice have concluded that A? oligomers in the extracellular space can profoundly affect synaptic structure and function. As soluble proteins, oligomers of A? can diffuse through brain tissue and can presumably exit acute slices, but the rate of loss of A? species by diffusion from brain slices and the resulting reduced concentrations of A? species in brain slices are unknown.
Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America. jackwaters@northwestern.edu