title: Hydrogen sulfide-induced enhancement of gastric fundus smooth muscle tone is mediated by voltage-dependent potassium and calcium channels in mice.
abstract: OBJECTIVE
  To investigate the effect of hydrogen sulfide (H2S) 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 H2S 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 H2S, 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).
  
  
  CONCLUSIONS
  These findings suggest that H2S 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.
authors.affiliation: Xiang-Min Meng, Xu Huang, Chun-Mei Zhang, Dong-Hai Liu, Hong-Li Lu, Wen-Xie Xu, Department of Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200240, China.
authors.forename: Xiang-Min
authors.initials: XM
authors.lastname: Meng
authors.affiliation: Xiang-Min Meng, Xu Huang, Chun-Mei Zhang, Dong-Hai Liu, Hong-Li Lu, Wen-Xie Xu, Department of Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200240, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Huang
authors.affiliation: Xiang-Min Meng, Xu Huang, Chun-Mei Zhang, Dong-Hai Liu, Hong-Li Lu, Wen-Xie Xu, Department of Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200240, China.
authors.forename: Chun-Mei
authors.initials: CM
authors.lastname: Zhang
authors.affiliation: Xiang-Min Meng, Xu Huang, Chun-Mei Zhang, Dong-Hai Liu, Hong-Li Lu, Wen-Xie Xu, Department of Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200240, China.
authors.forename: Dong-Hai
authors.initials: DH
authors.lastname: Liu
authors.affiliation: Xiang-Min Meng, Xu Huang, Chun-Mei Zhang, Dong-Hai Liu, Hong-Li Lu, Wen-Xie Xu, Department of Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200240, China.
authors.forename: Hong-Li
authors.initials: HL
authors.lastname: Lu
authors.affiliation: Xiang-Min Meng, Xu Huang, Chun-Mei Zhang, Dong-Hai Liu, Hong-Li Lu, Wen-Xie Xu, Department of Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200240, China.
authors.forename: Young-Chul
authors.initials: YC
authors.lastname: Kim
authors.affiliation: Xiang-Min Meng, Xu Huang, Chun-Mei Zhang, Dong-Hai Liu, Hong-Li Lu, Wen-Xie Xu, Department of Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200240, China.
authors.forename: Wen-Xie
authors.initials: WX
authors.lastname: Xu
mesh_terms: D000818:Animals; D002120:Calcium Channel Agonists / Q000494:pharmacology*; D020746:Calcium Channels, L-Type / Q000187:drug effects* / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects; D002478:Cells, Cultured; D003542:Cystathionine gamma-Lyase / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005748:Gastric Fundus / Q000187:drug effects* / Q000378:metabolism; D005769:Gastrointestinal Motility / Q000187:drug effects*; D006862:Hydrogen Sulfide / Q000494:pharmacology*; D008190:Lyases / Q000037:antagonists & inhibitors / Q000378:metabolism; D008297:Male; D008564:Membrane Potentials; D008813:Mice, Inbred ICR; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D026902:Potassium Channel Blockers / Q000494:pharmacology*; D024642:Potassium Channels, Voltage-Gated / Q000037:antagonists & inhibitors* / Q000378:metabolism; D013997:Time Factors
chemical_list: D002120:Calcium Channel Agonists; D020746:Calcium Channels, L-Type; D004791:Enzyme Inhibitors; D026902:Potassium Channel Blockers; D024642:Potassium Channels, Voltage-Gated; D019001:Nitric Oxide Synthase; D008190:Lyases; D003542:Cystathionine gamma-Lyase; C019965:cystathionine beta-lyase; D006862:Hydrogen Sulfide
keywords: Gastric fundus smooth muscle; Hydrogen sulfide; L-type calcium channel; Tension; Voltage-dependent potassium channel