ATPによるラット食道平滑筋の弛緩反応に対するカリウムチャネルの関与

• Published in: 日本薬理学会年会要旨集 p. 3-B-P-256
• Main Authors: 椎名, 貴彦, 志水, 泰武
• Format: Journal Article
• Language: Japanese
• Published: 公益社団法人 日本薬理学会 2022
• Subjects: ATP; esophagus; K+ channel; smooth muscle
• ISSN: 2435-4953
• DOI: 10.1254/jpssuppl.96.0_3-B-P-256

The external muscle layer of the mammalian esophagus consists of striated muscle fibers and smooth muscle fibers. Striated muscle is mainly regulated by cholinergic signaling, whereas smooth muscle is regulated by cholinergic and non-cholinergic signaling in the esophagus. ATP is a representative non-cholinergic extracellular transmitter, which control smooth muscle motility in the blood vessels and gastrointestinal tracts via purinergic receptors. We have demonstrated that exogenous application of ATP evokes relaxation of smooth muscle in the muscaris mucosa of the rat esophagus. In the present study, the aim was to clarify involvement of potassium channels in purinergic relaxation of the esophageal smooth muscle. An isolated segment of the rat esophagus was placed in an organ bath and the mechanical responses were recorded using a force transducer. After contraction of esophageal smooth muscle was induced by carbachol, we applied ATP, which evoked relaxation of smooth muscle. On the other hand, ATP did not affect high-potassium induced contraction. Pre-application of an antagonist of ATP-dependent potassium channels (KATP channels) blocked ATP-induced relaxation, but not voltage-gated potassium channel blockers. These findings indicate that KATP channels might be involved in ATP-induced relaxation of the esophageal smooth muscle in rats.