JNK/c-Jun inhibitor SP600125 attenuates amyloid β (Aβ) 1-42-induced upregulation of growth arrest and DNA damage-inducible gene 34 (GADD34). A, SH-SY5Y cells were treated with Aβ1-42 in the presence or absence of 50 nmol/L of specific c-Jun N-terminal kinases (JNK) inhibitor SP600125; the level of phosphor-c-Jun was measured by Western blot analysis (*P < .01, compared to nontreatment; #P < .01, compared to Aβ1-42 treatment, n = 4). B, SH-SY5Y cells were treated with Aβ1-42 in the presence or absence of 50 nmol/L of specific JNK inhibitor SP600125, the amount of GADD34 protein was measured by Western blot analysis (*P < .01, compared to nontreatment; #P < .01, compared to Aβ1-42 treatment, n = 4).