Figure 6.

cGMP/PKG inhibitors were not able to antagonize the inhibitory response of YC-1 in LPS-stimulated microglia. BV-2 microglia were pretreated with ODQ (10 μM), KT5823 (2 μM) or Rp-8-Br-PET-cGMPS (2 μM) for 15 min, followed by vehicle or YC-1 (10 μM) for 20 min, and then stimulated with LPS (100 ng ml⁻¹) for different time intervals (6 h: κB-luciferase (a); 18 h: iNOS and COX-2 (b) protein expression). The data represent the mean±s.e.m. from at least five independent experiments. ^*P<0.05, significantly different from LPS alone. NS, not significant. (c) Pretreatment of various concentrations of the guanylate cyclase inhibitor, ODQ (10, 50 or 200 μM) or PKG inhibitor, Rp-8-Br-PET-cGMPS (2, 10 or 50 μM) and the cell lysates were prepared for the determination of protein levels of iNOS and COX-2. The data represent the mean±s.e.m. (n=6). Note that the inhibitory effect of YC-1 on LPS-induced NF-κB luciferase activity and iNOS and COX-2 protein expression was not antagonized by sGC or PKG inhibitors.