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Shiina T, Suzuki Y, Horii K, Sawamura T, Yuki N, Horii Y, Shimizu Y. Purinergic inhibitory regulation of esophageal smooth muscle is mediated by P2Y receptors and ATP-dependent potassium channels in rats. J Physiol Sci 2024; 74:26. [PMID: 38654149 PMCID: PMC11036717 DOI: 10.1186/s12576-024-00916-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 03/20/2024] [Indexed: 04/25/2024]
Abstract
Purines such as ATP are regulatory transmitters in motility of the gastrointestinal tract. The aims of this study were to propose functional roles of purinergic regulation of esophageal motility. An isolated segment of the rat esophagus was placed in an organ bath, and mechanical responses were recorded using a force transducer. Exogenous application of ATP (10-100 μM) evoked relaxation of the esophageal smooth muscle in a longitudinal direction under the condition of carbachol (1 μM) -induced precontraction. Pretreatment with a non-selective P2 receptor antagonist, suramin (500 μM), and a P2Y receptor antagonist, cibacron blue F3GA (200 μM), inhibited the ATP (100 μM) -induced relaxation, but a P2X receptor antagonist, pyridoxal phosphate-6-azophenyl-2,4-disulfonic acid (50 μM), did not affect it. A blocker of ATP-dependent potassium channels (KATP channels), glibenclamide (200 μM), inhibited the ATP-induced relaxation and application of an opener of KATP channels, nicorandil (50 μM), produced relaxation. The findings suggest that ATP is involved in inhibitory regulation of the longitudinal smooth muscle in the muscularis mucosae of the rat esophagus via activation of P2Y receptors and then opening of KATP channels.
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Affiliation(s)
- Takahiko Shiina
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan.
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan.
| | - Yuji Suzuki
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan
| | - Kazuhiro Horii
- Division of Biological Principles, Department of Physiology, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan
| | - Tomoya Sawamura
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan
| | - Natsufu Yuki
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan
| | - Yuuki Horii
- Institute for Glyco-Core Research (iGCORE), Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan
| | - Yasutake Shimizu
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan
- Division of Animal Medical Science, Center for One Medicine Innovative Translational Research (COMIT), Gifu University Institute for Advanced Study, 1-1 Yanagido, Gifu, 501-1193, Japan
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Khoshavi Najafabadi F, Sadraei H, Mehranfard N, Ghasemi M. Motor Dysfunction of Gastric Antral Smooth Muscle in Diabetic Rats: Contribution of ATP-Dependent Potassium Channels. Adv Biomed Res 2023; 12:199. [PMID: 37694236 PMCID: PMC10492619 DOI: 10.4103/abr.abr_44_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 05/14/2023] [Accepted: 05/20/2023] [Indexed: 09/12/2023] Open
Abstract
Background The goal of the current research was to further elucidate the role of adenosine triphosphate (ATP)-sensitive potassium (KATP) channels in the motility and contractility force of gastric smooth muscle of diabetic rats. Materials and Methods Male Wistar rats (190-230 g) were grouped into control and streptozotocin (STZ)-induced diabetes (55 mg/kg) rats. Thirty days later, gastric muscle contractility was measured using a myograph and a force transducer of antral segments immersed in a tissue bath. Gastric emptying response was measured through feeding of standard pellet. Furthermore, the expression of KATP channel subunits in antral smooth muscle was determined by western blot technique. Results The amplitude of KCl-evoked twitch contractions of diabetic antral strips was about 25% more than control (P < 0.05). Application of minoxidil, a KATP channel opener, dose dependently decreased the force of twitch contractions in both normal and diabetic antral strips. Application of 10 μM glibenclamide, a KATP channel blocker, did not antagonize the minoxidil-induced relaxation of antral strips. Diabetic gastric emptying was faster than normal, although not significant. Despite the relaxant effect of minoxidil on gastric emptying rate in normal rats (P < 0.05), this effect was not observed in diabetic rats. Also, glibenclamide increased gastric emptying and antagonized minoxidil-induced relaxation in normal rats (P < 0.05). Furthermore, the expression of KATP Kir6.1 and SUR2B subunits was substantially reduced in antral smooth muscle in diabetic condition (P < 0.01). Conclusion These results propose that KATP channels may contribute to the development of gastric motility disorders in diabetes.
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Affiliation(s)
- Fatameh Khoshavi Najafabadi
- Department of Pharmacology and Toxicology, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Hassan Sadraei
- Department of Pharmacology and Toxicology, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Nasrin Mehranfard
- Neurophysiology Research Center, Cellular and Molecular Medicine Research Institute, Urmia University of Medical Sciences, Urmia, Iran
| | - Maedeh Ghasemi
- Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
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