Quantitative analysis of MNP uptake in PC12 cells and primary neurons. All values are expressed as mean ± SD. (A) compares the percentage of primary neurons in cerebellar cultures and (B) the percentage of differentiated PC12 cells of control cells and cells after MNP incubation. MNP incubation induced no changes in the number of neurons and PC12 cells. (C) compares the number of both cell types which took up MNPs. Significantly more PC12 cells took up MNPs than primary neurons.