Fig. 7. Regulation of the endogenous H₂S production in different rat tissues. (A) Accumulated endogenous H₂S levels in rat tail artery (TA), mesenteric artery (MA), aorta and ileum. (B) H₂S production rate of aorta tissues was stimulated by SNP in a concentration-dependent manner. *P < 0.05 compared with control, n = 3. (C) The SNAP-induced concentration-dependent upregulation of CSE transcriptional expression in cultured aortic SMCs, determined using northern blotting. The 28S ribosome RNA was assayed as the housekeeping control. n = 3, *P < 0.05 compared with control.