In recent years, transgenic mice have become valuable tools for studying mechanisms of Alzheimer's disease (AD). With the aim of developing an animal model better for memory and neurobehavioural testing, we have generated a transgenic rat model of AD. These animals express human amyloid precursor protein (APP) containing the Swedish AD mutation. The highest level of expression in the brain is found in the cortex, hippocampus, and cerebellum. Starting after the age of 15 months, the rats show increased tau phosphorylation and extracellular A staining. The AP is found predominantly in cerebrovascular blood vessels with very rare diffuse plaques. We believe that crossing these animals with mutant PSI transgenic rats will result in accelerated plaque formation similar to that seen in transgenic mice. (c) 2007 Elsevier Inc. All rights reserved.