Figure 4.

Aβ_1–42 toxicity of basal forebrain cholinergic neurons in vivo is prevented by p75^NTR deficiency. The hippocampi of wild-type (WT) and p75^NTR knock-out (KO) mice were injected with Aβ, and after 14 d the number of ChAT-positive cells in each hemisphere was counted. A, The number of wild-type ChAT-positive neurons in the hemisphere ipsilateral to the Aβ_1–42 injection site was significantly reduced compared with that in uninjected or Aβ_1–16-injected animals. The numbers of ChAT-positive neurons in p75^NTR-deficient mice after injection with Aβ_1–16 or Aβ_1–42 were not significantly different, and were similar also to that found in uninjected wild-type mice. n ≥ 4 per condition; ***p < 0.001. B, C, Photomicrographs of ChAT-positive cells in the basal forebrain of wild-type (B) and p75^NTR-deficient (C) mice 14 d after injection with Aβ.