Figure 2.

Dipyrone inhibits neuronal cell death of PCNs challenged by OGD. PCNs were pretreated for 2 hours with dipyrone over a wide range of concentrations (0.1 to 1000 nM), and then subjected to 3 hours of OGD. Cell death was evaluated by the LDH assay 16 hours after completion of OGD. Data from three independent experiments are presented as mean ± S.E.M. A, The extent of cell death is graphed against dipyrone concentration. Values are normalized with respect to the release of LDH in a null control (i.e., a cell culture that was not drug-treated and was never challenged by OGD). The black bar corresponds to the extent of cell death upon challenge with OGD in the absence of drug. Each grey bars corresponds to the extent of cell death upon OGD-treatment in the presence of the indicated concentration of dipyrone. ##, P < 0.01 versus the null control (i.e., cells not subject to OGD and not treated with dipyrone). *, P < 0.05; **, P < 0.01 versus the OGD-treated culture without dipyrone. B, The sigmoidal dose-response fitting curve is generated by the Graphpad Prism 4 software (Graphpad Software Inc., San Diego, CA). The data in figure A are plotted as a semi-logarithmic graph of the extent of cell death as a function of dipyrone concentration. The IC₅₀ for dipyrone is 0.2 nM and the maximum protection is 81%.