Effect of NaHS (a) and L-cysteine (b) on the gastric mucosal mRNA expression of COX-2. (a) Analysis of semiquantitative real-time PCR results showed that the administration of NaHS increased the mRNA expression of COX-2. C: control, NaHS: animals received NaHS (80 μg/kg, i.v.) just prior to stimulation of the gastric acid secretion, NaHS + L-NAME: animals received L-NAME at 10 mg/kg, i.v., 5 min before the administration of NaHS (80 μg/kg, i.v.), and PAG: rats received cystathionine-γ-lyase inhibitor, propargylglycine (PAG), at 50 mg/kg, i.v. concomitant with the gastric distention. (b) Animals received normal saline at 2 mL/kg, i.p. (C: control), or L-cysteine at 50 mg/kg, i.p. (L-cys), once a day for five days before stimulation of the gastric acid secretion. Asterisks indicate a significant increase (*P < 0.01) as compared to the control group; χ
P < 0.05 indicates a significant decrease as compared with the control. Data are expressed as mean ± S.E.M.