Home
Resources
Publications
Endogenous Hydrogen Sulfide Contributes to Tone Generation in Porcine Lower Esophageal Sphincter Via Na +/Ca 2+ Exchanger

Endogenous Hydrogen Sulfide Contributes to Tone Generation in Porcine Lower Esophageal Sphincter Via Na +/Ca 2+ Exchanger

Xiaopeng Bai, Eikichi Ihara, Katsuya Hirano, Yoshimasa Tanaka, Kayoko Nakano, Satomi Kita, Takahiro Iwamoto, Haruei Ogino, Mayumi Hirano, Yoshinao Oda, Kazuhiko Nakamura, Yoshihiro Ogawa

Cell Mol Gastroenterol Hepatol. 2017 Nov 22;5(3):209-221.

PMID: 29379856

Abstract:

Background and aims:
Hydrogen sulfide (H2S) is a major physiologic gastrotransmitter. Its role in the regulation of the lower esophageal sphincter (LES) function remains unknown. The present study addresses this question.
Methods:
Isometric contraction was monitored in circular smooth muscle strips of porcine LES. Changes in cytosolic Ca2+ concentration ([Ca2+]i) and force were simultaneously monitored in fura-2-loaded strips with front-surface fluorometry. The contribution of endogenous H2S to LES contractility was investigated by examining the effects of inhibitors of H2S-generating enzymes, including cystathionine-β-synthase, cystathionine-γ-lyase, and 3-mercaptopyruvate sulfurtransferase, on the LES function.
Results:
Porcine LES strips myogenically maintained a tetrodotoxin-resistant basal tone. Application of AOA (cystathionine-β-synthase inhibitor) or L-aspartic acid (L-Asp; 3-mercaptopyruvate sulfurtransferase inhibitor) but not DL-PAG (cystathionine-γ-lyase inhibitor), decreased this basal tone. The relaxant effects of AOA and L-Asp were additive. Maximum relaxation was obtained by combination of 1 mM AOA and 3 mM L-Asp. Immunohistochemical analyses revealed that cystathionine-β-synthase and 3-mercaptopyruvate sulfurtransferase, but not cystathionine-γ-lyase, were expressed in porcine LES. AOA+L-Asp-induced relaxation was accompanied by a decrease in [Ca2+]i and inversely correlated with the extracellular Na+ concentration ([Na+]o) (25-137.4 mM), indicating involvement of an Na+/Ca2+ exchanger. The reduction in the basal [Ca2+]i level by AOA was significantly augmented in the antral smooth muscle sheets of Na+/Ca2+ exchanger transgenic mice compared with wild-type mice.
Conclusions:
Endogenous H2S regulates the LES myogenic tone by maintaining the basal [Ca2+]i via Na+/Ca2+ exchanger. H2S-generating enzymes may be a potential therapeutic target for esophageal motility disorders, such as achalasia.

Chemicals Related in the Paper:

Catalog Number	Product Name	Structure	CAS Number	Price
AP16873135	Tetraethylammonium hydrogen sulfate		16873-13-5	Price

As a specialist in analytical chemical Products, Alfa Chemistry offers consumers a wealth of raw materials and a full range of technologies and services.

QUICK LINKS

HEADQUARTERS

Tel:

Fax:

Email: