Figure 1. Validation of the selectivity of iNOS inhibition by 1400W.

Isolated rat lungs were perfused with buffer in recirculatory mode and underwent an IR cycle comprised of 90(A) NOS assays conducted in lung homogenates after IR experiments without intervention (n = 6 each) showing that 1400W inhibited iNOS (Ca/CaM-independent activity) with sufficient selectivity over constitutive NOS. L-NAME, a non-selective NOS inhibitor, was given at 100 µM, 1400W, a selective iNOS inhibitor, at 1 µM, and SMTC, an nNOS inhibitor, at 10 µM. (B) In another subset of lungs (n = 6 each), L-NAME, 1400W, SMTC, or relaxin (5 nM) were exclusively administered either during ischemia or during reperfusion. Here, the wet-to-dry ratio is shown which was representative for all other readouts. While L-NAME affected both ischemia and reperfusion 1400W impacted only on reperfusion; relaxin (when not applied during the full IR cycle) had no effect. There was no relevant effect of nNOS inhibition at all. P<0.05; *vs. control.