Mechanisms of peroxynitrite-induced [Ca2+]i increase in single neuronal cell

The mechanism of peroxynitrite (ONOO⁻)-induced ca²⁺]_i increase in single MN9D cell (Dopaminergic neuroblastoma cell line) was studied by using Fura-2 microfluorometric technique. The results show that ONOO⁻ caused a rapid increase of Ca²⁺]_i when ONOO₋ was puffed to the cell. Removing Ca²⁺ from the bath or using calcium channel antagonist (CdCl₂, Nifedipine) greatly inhibited the Ca²⁺]_i increase induced by ONOO⁻¹, suggesting that the opening of L-Ca²⁺ channel makes a great contribution to the Ca²⁺]_i increase. The effect of sulfhydryl reductive agent (DTT) on ONOO⁻-induced Ca²⁺]_i increase suggests that ONOO⁻-activating L-Ca²⁺ channel is partly related to its oxidative speciality.