BACKGROUND: Complementary receptors have been suggested to play causative roles in the neuroinflammatory process of Alzheimer's disease (AD). The genetic expressions of the C3a receptor (C3aR), C5a receptor (C5aR) and the protein expressions of the C3aR and C5aR were examined in the human neuroblastoma cell line, SK-N-SH, after the administration of amyloid peptide (A1-42). METHODS: SK-N-SH cells were incubated overnight with a single dose of 20 M of aggregated A (A1-42). An inhibition study was done with actinomycin D (ActD, 2.5 M) or with the administration of cycloheximide (CHX, 2.5 M) to the cell suspension. Messenger RNA expressions of C3aR and C5aR were detected by RT-PCR. The intensity of bands from 6% polyacrylamide electrophoretic gel was analyzed by a bioimage analyzer. The protein production of C3aR and C5aR in the A-treated cells was also measured by flow cytometry. NFB activation after treatment of A in the cells was detected by an electrophoretic mobility-shift assay. RESULTS: A1-42 increased the expression of C3aR and C5aR. ActD inhibited the expression of both anaphylatoxin receptors but CHX only suppressed C5aR mRNA expression. Activated NFB was demonstrated in the A-stimulated cells. CONCLUSIONS: C3aR and C5aR were constitutively expressed in the human neuroblastoma SK-N-SH cell. Expression of these anaphylatoxin receptors was upregulated after A1-42 stimulation, which as a result, may contribute to the complement-mediated neuroinflammation of AD.