Fig. 7.
cGMP synthesis by soluble guanylyl cyclase (sGC) protects the glomerular filtration barrier. Isolated glomeruli were incubated with reagents as described for 15 min at 37°C. Control glomeruli were incubated with equivalent volume of the vehicle (incubation medium containing 5% BSA). Palb values are presented as means ± SE derived from measurements made in 15 glomeruli isolated from 3 rats (5 glomeruli from each rat). A: effect of cGMP analog on ADMA-induced increase in Palb. Isolated rat glomeruli were incubated with ADMA (5 μM) alone or ADMA (5 μM) and 8-Br-cGMP (1, 10, or 100 nM). ADMA increased Palb. 8-bromo-cGMP at 100 nM concentration significantly abrogated this increase (*P < 0.001 vs. ADMA alone). B: effect of BAY 41-2272 on ADMA-induced increase in Palb. Isolated rat glomeruli were incubated with ADMA (5 μM) alone or ADMA (5 μM) in the presence of various concentrations of BAY 41-2272 (1, 5, or 10 μg/ml). ADMA alone increased Palb. BAY 41-2272 (5 or 10 μg/ml) significantly prevented the increase in Palb (*P < 0.005 vs. control). C: effect of sGC inhibitor ODQ on Palb. Isolated rat glomeruli were incubated with ODQ (1, 2, 5, or 10 μM) alone. Additional aliquot of glomeruli was incubated with 10 μM ODQ and 100 μM 8-Br-cGMP. ODQ alone (5 and 10 μM) increased Palb (*P < 0.005 vs. control). Inclusion of 8-Br-cGMP blocked the effect of ODQ (**P < 0.001).