Hydrogen sulfide-induced enhancement of gastric fundus smooth muscle tone is mediated by voltage-dependent potassium and calcium channels in mice
Hydrogen sulfide-induced enhancement of gastric fundus smooth muscle tone is mediated by voltage-dependent potassium and calcium channels in mice
复制标题
硫化氢诱导的小鼠胃底平滑肌张力增强是由电压依赖性钾和钙通道介导的。
DOI：
10.3748/wjg.v21.i16.4840
复制
发表时间：
2015-04-28
影响因子：
4.3
通讯作者：
Xu, Wen-Xie
中科院分区：
文献类型：
--
作者：
Meng, Xiang-Min;Huang, Xu;Xu, Wen-Xie
目的：探讨硫化氢(H2 S)对胃底平滑肌运动的影响。方法：采用免疫细胞化学技术检测培养的胃底平滑肌细胞中胱硫醚β合成酶(Cbs)和胱硫氨酸γ裂解酶(Cse)的表达。在等长收缩条件下，用等长力传感器记录胃底肌条的张力，并用丝线系住胃底肌条。细胞内记录用于确定硫化氢是否影响体外培养的胃底静息膜电位。采用多种酶消化法从小鼠胃底新鲜分离细胞，采用全细胞膜片钳技术观察硫化氢对小鼠胃底电压依赖性钾通道和钙通道的影响。结果：体外培养的小鼠胃底平滑肌细胞均表达CBS和CSE，低浓度的H2 S可使小鼠胃底平滑肌细胞张力增加。尼卡地平和一氧化氮合酶抑制剂氨基氧乙酸使张力降低，而非特异性一氧化氮合酶N-ω-硝基-L-精氨酸甲酯使张力增加。5μ/L 4-氨基吡啶和1 mmoL/L尼卡地平可阻断NaHS引起的紧张性收缩增加。NaHS显著去极化膜电位，抑制电压依赖性钾电流。此外，NaHS使小鼠胃底L型钙电流增加，细胞内钙离子浓度升高。结论：H2 S可能是小鼠胃底兴奋性调节剂。这种兴奋作用是由电压依赖性钾通道和L型钙通道介导的。
AIM: To investigate the effect of hydrogen sulfide (H 2 S) on smooth muscle motility in the gastric fundus.METHODS: The expression of cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE) in cultured smooth muscle cells from the gastric fundus was examined by the immunocytochemistry technique. The tension of the gastric fundus smooth muscle was recorded by an isometric force transducer under the condition of isometric contraction with each end of the smooth muscle strip tied with a silk thread. Intracellular recording was used to identify whether hydrogen sulfide affects the resting membrane potential of the gastric fundus in vitro. Cells were freshly separated from the gastric fundus of mice using a variety of enzyme digestion methods and whole-cell patch-clamp technique was used to find the effects of hydrogen sulfide on voltage-dependent potassium channel and calcium channel. Calcium imaging with fura-3AM loading was used to investigate the mechanism by which hydrogen sulfide regulates gastric fundus motility in cultured smooth muscle cells.RESULTS: We found that both CBS and CSE were expressed in the cultured smooth muscle cells from the gastric fundus and that H 2 S increased the smooth muscle tension of the gastric fundus in mice at low concentrations. In addition, nicardipine and aminooxyacetic acid (AOAA), a CBS inhibitor, reduced the tension, whereas Nω-nitro-L-arginine methyl ester, a nonspecific nitric oxide synthase, increased the tension. The AOAA-induced relaxation was significantly recovered by H 2 S, and the NaHS-induced increase in tonic contraction was blocked by 5 mmol/L 4-aminopyridine and 1 μmol/L nicardipine. NaHS significantly depolarized the membrane potential and inhibited the voltage-dependent potassium currents. Moreover, NaHS increased L-type Ca 2+ currents and caused an elevation in intracellular calcium ([Ca 2+] i).CONCLUSION: These findings suggest that H 2 S may be an excitatory modulator in the gastric fundus in mice. The excitatory effect is mediated by voltage-dependent potassium and L-type calcium channels.