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- Title
Exogenous H<sub>2</sub>S enhances mice gastric smooth muscle tension through S-sulfhydration of K<sub>V</sub>4.3, mediating the inhibition of the voltage-dependent potassium current.
- Authors
Liu, D.-H.; Huang, X.; Meng, X.-M.; Zhang, C.-M.; Lu, H.-L.; Kim, Y.-C.; Xu, W.-X.
- Abstract
Background Hydrogen sulfide ( H2S) has been shown to have an excitatory effect on gastric motility, but the underlying molecular mechanism is unclear. In this study, we aimed to investigate the possible targets of H2S and determine how H2S affects its target proteins during H2S-induced contraction. Methods Patch-clamp and potentiometric fluorescence dye were utilized to measure the electrophysiological changes. The Biotin-switch assay was utilized to detect the protein S-sulfhydration. The isometric tension measurement was conducted too. Key Results Exogenous H2S enhanced the tonic contraction of gastric antral smooth muscle, and voltage-dependent potassium channel (KV) blocker and Dithiothreitol ( DTT, a reducing agent) abolished the excitatory effect of NaHS. Exogenous H2S inhibited the fast inactivation component of the voltage-dependent potassium channel current (IKVfast) in isolated gastric antral smooth muscle cells. H2S inhibited the KV4.3 current in H293 cells with heterologous expression of KV4.3, but did not inhibit the KV4.1 and KV4.2 currents, which together contribute greatly to IKVfast. NaHS significantly decreased the membrane potential in cultured gastric smooth muscle cells, but the NaHS-induced depolarization was suppressed by knockdown of KV4.3 and N-ethylamaleimide ( NEM), a free thiol group blocker. In addition, NaHS sulfhydrated KV4.3 in H293 cells and in gastric smooth muscle tissue. However, this S-sulfhydration was inhibited by NEM and DTT. Meanwhile the NaHS-induced inhibition of IKVfast and KV4.3 was also blocked by NEM and DTT. Conclusions & Inferences These results suggest that exogenous H2S sulfhydrates KV4.3 to decrease the membrane potential, thereby enhancing the basal tension of gastric antral smooth muscle.
- Subjects
SMOOTH muscle physiology; GASTROINTESTINAL motility; HYDROGEN sulfide; MOLECULAR pathology; MEMBRANE potential; ELECTROPHYSIOLOGY
- Publication
Neurogastroenterology & Motility, 2014, Vol 26, Issue 12, p1705
- ISSN
1350-1925
- Publication type
Article
- DOI
10.1111/nmo.12451