AGTR1 and Alzheimer disease: In addition, the AT1 receptor is expressed in brain regions relevant to learning, memory, and AD (e.g., hippocampus and cerebral cortex) in mice (Allen et al., 1998), rats (Lenkei et al., 1997), gerbils (Tonelli et al., 2000), dogs (Speth et al., 1985), and humans (MacGregor et al., 1995).