Fig. 2. Fibrillar Aβ1–42, but not Aβ42–1, peptides induce the production of ceramide and the activation of neutral (N-SMase) and acidic (A-SMase) sphingomyelinases in human primary neurons.
Cells were incubated with 1 μm of fibrillar Aβ1–42, fibrillar Aβ42–1, or soluble Aβ1–42 in Neurobasal medium containing 2% B27-AO for different time intervals. Lipids were extracted, and ceramide and DAG contents (A) were determined. a, p < 0.001 versus control. B, after 6 h of incubation with different concentrations of Aβ1–42, ceramide contents were determined. b, p < 0.05 versus control. C, after incubation with either fibrillar Aβ1–42 or Aβ42–1 at 1 μm for different time intervals, activities of N-SMase and A-SMase were assayed in total cell extract.