Department of Physiology, Shanghai Jiao Tong University School of Medicine, 800 Dongchuan Road, Minhang, 328 Wenxuan Medical Building, Shanghai 200240, China.
Eur J Pharmacol. 2013 Nov 15;720(1-3):276-85. doi: 10.1016/j.ejphar.2013.10.017. Epub 2013 Oct 21.
NO and H2S are gaseous signaling molecules that modulate smooth muscle motility. We aimed to identify expressions of enzymes that catalyze H2S and NO generation in mouse gastric smooth muscle, and determine relationships between endogenous H2S and NO in regulation of smooth muscle motility. Western blotting and immunocytochemistry methods were used to track expressions of neuronal nitric oxide synthase (nNOS), endothelial nitric oxide synthase (eNOS), cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE) in gastric smooth muscles. Smooth muscle motility was recorded by isometric force transducers. cGMP production was measured by a specific radioimmunoassay. We found that CBS, CSE, eNOS, and nNOS were all expressed in mice gastric antral smooth muscle tissues, and in cultured gastric antral smooth muscle cells. AOAA significantly inhibited smooth muscle contractions in the gastric antrum, which was significantly recovered by NaHS, while PAG had no significant effect. l-NAME enhanced contractions. NaHS at low concentrations increased basal tension but decreased it at high concentrations. SNP significantly inhibited the contractions, which could be recovered by NaHS both in the absence and presence of CuSO4. ODQ did not block NaHS-induced excitatory effect, while IBMX partially blocked this effect. cGMP production in smooth muscle was significantly increased by SNP but was not affected by NaHS. All these results suggest that endogenous H2S and NO appear to play opposite roles in regulating gastric motility and their effects may be via separate signal transduction pathways. Intracellular H2S/NO levels may be maintained in a state of balance to warrant normal smooth muscle motility.
NO 和 H2S 是调节平滑肌运动的气态信号分子。我们旨在鉴定在小鼠胃平滑肌中催化 H2S 和 NO 生成的酶的表达，并确定内源性 H2S 和 NO 在调节平滑肌运动中的关系。使用 Western 印迹和免疫细胞化学方法跟踪胃平滑肌中神经元型一氧化氮合酶（nNOS）、内皮型一氧化氮合酶（eNOS）、胱硫醚-β-合酶（CBS）和胱硫醚-γ-裂解酶（CSE）的表达。通过等长力换能器记录平滑肌运动。通过特定的放射免疫测定法测量 cGMP 产生。我们发现 CBS、CSE、eNOS 和 nNOS 均在小鼠胃窦平滑肌组织和培养的胃窦平滑肌细胞中表达。AOAA 显著抑制胃窦平滑肌收缩，NaHS 可显著恢复，而 PAG 无明显作用。l-NAME 增强收缩。低浓度的 NaHS 增加基础张力，但高浓度时则降低。SNP 显著抑制收缩，CuSO4 存在或不存在时均可被 NaHS 恢复。ODQ 不阻断 NaHS 诱导的兴奋作用，而 IBMX 部分阻断该作用。SNP 可显著增加平滑肌中环磷酸鸟苷的产生，但 NaHS 无影响。所有这些结果表明，内源性 H2S 和 NO 似乎在调节胃动力方面发挥相反的作用，其作用可能通过独立的信号转导途径。细胞内 H2S/NO 水平可能保持平衡状态，以保证正常的平滑肌运动。
