DEP up-regulation of P-glycoprotein involves NO synthase, JNK, and c-jun. A) Western blot showing that DEPs increase expression of iNOS, but not of bNOS. B) Inhibition of NOS with L-NMMA abolishes the DEP-mediated induction of P-glycoprotein expression and transport activity. C) An NF-κB activation inhibitor has no effect on DEP up-regulation of P-glycoprotein. D) SN50, an inhibitor of NF-κB nuclear translocation, and SN50M, the corresponding inactive control peptide, also have no effect on DEP up-regulation of P-glycoprotein. E) Inhibition of JNK with SP600125 blocks the DEP-mediated increase of P-glycoprotein expression (Western blot) and transport activity (specific luminal NBD-CSA fluorescence). F) Western blot showing that DEPs increase phosphorylated c-jun (c-jun-P) in capillaries exposed to DEPs for 6 h; c-jun expression was slightly decreased. Specific luminal NBD-CSA fluorescence values are means ± se for 10 capillaries from a single preparation (pooled tissue from 10 rats); scale 0–255 au. ***P < 0.001.