Fig. 3.
Pretreatment with the endothelial nitric oxide (NO) synthase inhibitor Nω-nitro-l-arginine methyl ester (l-NAME; 500 μM) for 24 h before the addition of the tracer did not significantly alter the permeability of monolayers exposed to ASS (P = 0.08; A) or of the corresponding static controls (P = 0.58; B). It significantly increased the permeability of monolayers exposed to CSS (P = 0.002; C), reversing the influence of CSS, but again did not affect the corresponding static controls (P = 0.15; D). As in Fig 2, ASS increased permeability and CSS decreased it relative to static controls (P = 0.04 and 0.002, one-tailed). n = 18–25. ns, Not significant. **P < 0.01.