P2RX7 and Alzheimer disease: P2X7 receptors expression are also upregulated in the hippocampus of two animal models of AD, such as transgenic mice that express the human APP bearing the Swedish mutation (K670N/M671L) (Parvathenani et al., 2003) and rats injected with amyloid-β peptide (Aβ) 1-42 (1 nmol) into the hippocampus (McLarnon et al., 2006) (Figure 3).