Figure 4.

Sildenafil reverses JNK activation caused by malonate. Sildenafil (1.5 mg·kg⁻¹ p.o.) was administered 30 min before malonate injection (1.5 μmol/2 μL), and rats were killed 6 h later. (A) Quantitative measurement of p-JNK/JNK levels and representative Western blots showing that sildenafil inhibits the phosphorylation of JNK (46 and 54 kDa) induced by malonate. Note that the levels of p-JNK from sham and sildenafil groups were so weak that were not taken into account for statistical analysis. Data are means ± SEM (n = 5–9 animals for each group). Data analysed by Student's t-test revealed significant differences: for p-JNK 46 kDa [t₍₁₂₎ = 12.77, P < 0.001] and for p-JNK 54 kDa [t₍₁₂₎ = 8.330, P < 0.01]. (B) Sildenafil inhibits the increase in c-jun phosphorylation at Ser⁶³ shown in nuclear fractions. Data are mean ± SEM (n = 6 animals per group) [t₍₁₁₎ = 2.950, P < 0.05]. ^§P < 0.05, ^§§P < 0.01, ^§§§P < 0.001 versus malonate.