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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Kravenska Y, Checchetto V, Szabo I. Routes for Potassium Ions across Mitochondrial Membranes: A Biophysical Point of View with Special Focus on the ATP-Sensitive K + Channel. Biomolecules 2021; 11:1172. [PMID: 34439838 PMCID: PMC8393992 DOI: 10.3390/biom11081172] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 07/29/2021] [Accepted: 08/02/2021] [Indexed: 12/18/2022] Open
Abstract
Potassium ions can cross both the outer and inner mitochondrial membranes by means of multiple routes. A few potassium-permeable ion channels exist in the outer membrane, while in the inner membrane, a multitude of different potassium-selective and potassium-permeable channels mediate K+ uptake into energized mitochondria. In contrast, potassium is exported from the matrix thanks to an H+/K+ exchanger whose molecular identity is still debated. Among the K+ channels of the inner mitochondrial membrane, the most widely studied is the ATP-dependent potassium channel, whose pharmacological activation protects cells against ischemic damage and neuronal injury. In this review, we briefly summarize and compare the different hypotheses regarding the molecular identity of this patho-physiologically relevant channel, taking into account the electrophysiological characteristics of the proposed components. In addition, we discuss the characteristics of the other channels sharing localization to both the plasma membrane and mitochondria.
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Affiliation(s)
| | | | - Ildiko Szabo
- Department of Biology, University of Padova, 35131 Padova, Italy; (Y.K.); (V.C.)
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Horii K, Suzuki Y, Shiina T, Saito S, Onouchi S, Horii Y, Shimaoka H, Shimizu Y. ATP-dependent potassium channels contribute to motor regulation of esophageal striated muscle in rats. J Vet Med Sci 2019; 81:1266-1272. [PMID: 31292350 PMCID: PMC6785617 DOI: 10.1292/jvms.19-0197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The aim of the present study was to clarify roles of ATP-dependent potassium channels (KATP channels) in motility of the striated muscle portion in the esophagus. An isolated segment of the rat esophagus was placed in an organ bath and mechanical responses were recorded using a force transducer. Electrical stimulation of the vagus nerve evoked contractile response of striated muscle in the esophageal segment. Application of glibenclamide, an antagonist of KATP channels, increased amplitude of vagally mediated twitch contractions of the rat esophagus. On the other hand, minoxidil, an agonist of KATP channels, decreased amplitude of twitch contractions. RT-PCR revealed the expression of subunits of KATP channels in esophageal tissue. In addition, immunopositivity for subunits of KATP channels was observed in the striated muscle cells of the esophageal muscle layer. These findings indicate that KATP channels contribute to motor regulation of striated muscle in the rat esophagus.
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Affiliation(s)
- Kazuhiro Horii
- Department of Basic Veterinary Science, Laboratory of Physiology, The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagaido, Gifu 501-1193, Japan
| | - Yuji Suzuki
- Department of Basic Veterinary Science, Laboratory of Physiology, The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagaido, Gifu 501-1193, Japan
| | - Takahiko Shiina
- Department of Basic Veterinary Science, Laboratory of Physiology, The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagaido, Gifu 501-1193, Japan
| | - Shouichiro Saito
- Department of Basic Veterinary Science, Laboratory of Anatomy, The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagaido, Gifu 501-1193, Japan
| | - Sawa Onouchi
- Department of Basic Veterinary Science, Laboratory of Anatomy, The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagaido, Gifu 501-1193, Japan
| | - Yuuki Horii
- Department of Basic Veterinary Science, Laboratory of Physiology, The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagaido, Gifu 501-1193, Japan
| | - Hiroki Shimaoka
- Department of Basic Veterinary Science, Laboratory of Physiology, The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagaido, Gifu 501-1193, Japan
| | - Yasutake Shimizu
- Department of Basic Veterinary Science, Laboratory of Physiology, The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagaido, Gifu 501-1193, Japan.,Center for Highly Advanced Integration of Nano and Life Sciences (G-CHAIN), Gifu University, 1-1 Yanagaido, Gifu 501-1193, Japan
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Luppi P, Drain P. Uncoupling a unique couple by chopping off one of its tails: insights into the K ATP channels of the heart and pancreas. J Physiol 2018; 596:6135-6136. [PMID: 30387493 DOI: 10.1113/jp277099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Patrizia Luppi
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
| | - Peter Drain
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
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Zhang R, Zhou X, Shen X, Xie T, Xu C, Zou Z, Dong J, Liao L. Different sulfonylureas induce the apoptosis of proximal tubular epithelial cell differently via closing K ATP channel. Mol Med 2018; 24:47. [PMID: 30180807 PMCID: PMC6122448 DOI: 10.1186/s10020-018-0042-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 07/16/2018] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Sulfonylureas (SUs) are widely prescribed for the treatment of type 2 diabetes (T2DM). Sulfonylurea receptors (SURs) are their main functional receptors. These receptors are also found in kidney, especially the tubular cells. However, the effects of SUs on renal proximal tubular epithelial cells (PTECs) were unclear. METHODS Three commonly used SUs were included in this study to investigate if different SUs have different effects on the apoptosis of PTECs. HK-2 cells were exposed to SUs for 24 h prior to exposure to 30 mM glucose, the apoptosis rate was evaluated by Annexin/PI flow cytometry. Bcl-2, Bax and the ratio of LC3II to LC3I were also studied by western blot in vitro. Diazoxide was used to evaluate the role of KATP channel in SUs-induced apoptosis of PTECs. A Student's t-test was used to assess significance for data within two groups. RESULTS Treatment with glibenclamide aggravated the apoptosis of HK-2 cells in high-glucose, as indicated by a significant decrease in the expression of Bcl-2 and increase in Bax. Additionally, the decreased LC3II/LC3I reflects that the autophagy was inhibited by glibenclamide. Similar but less pronounced change was found in glimepiride group, however, nearly opposite effects were found in gliclazide group. Further, the effects of glibenclamide on apoptosis promotion and the decreased LC3II/LC3I were ameliorated obviously by treatment with 100uM diazoxide. The potential protection effect of gliclazide was also inhibited after opening the KATP channel. CONCLUSION Our results suggest that, the effects of glibenclamide and glimepiride on PTECs apoptosis, especially the former, were achieved in part by closing the KATP channel. In contrast to glibenclamide and glimepiride, therapeutic concentrations of gliclazide showed an inhibitory effect on apoptosis of PTECs, which may have a benefit in the preservation of functional PTECs mass.
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Affiliation(s)
- Rui Zhang
- Department of Endocrinology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong, China
| | - Xiaojun Zhou
- Department of Endocrinology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong, China
| | - Xue Shen
- Division of Endocrinology, Department of Internal Medicine, Shandong University of Traditional Chinese Medicine, Jinan, Shandong, China
| | - Tianyue Xie
- Division of Endocrinology, Department of Internal Medicine, Shandong University of Traditional Chinese Medicine, Jinan, Shandong, China
| | - Chunmei Xu
- Department of Endocrinology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong, China
| | - Zhiwei Zou
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Jianjun Dong
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, Shandong, China.
- Department of Internal Medicine, Division of Endocrinology, Qilu Hospital of Shandong University, No. 107, Wenhuaxi Road, Jinan, Shandong, China.
| | - Lin Liao
- Department of Endocrinology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong, China.
- Department of Internal Medicine, Division of Endocrinology, Shandong Provincial Qianfoshan Hospital, Shandong University, No. 16766, Jingshi Road, Jinan, Shandong, China.
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Ghazanfari A, Vigmond E, Nygren A. Arrhythmia Vulnerability in Diabetic Cardiac Tissue is Species-Dependent: Effects of I KATP, Uncoupling, and Connexin Lateralization. Cardiovasc Eng Technol 2017; 8:527-38. [PMID: 28656565 DOI: 10.1007/s13239-017-0315-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 06/22/2017] [Indexed: 10/19/2022]
Abstract
Amongst the complications of diabetes is arrhythmia, the risk of which depends on multiple factors. This study was designed to investigate several factors, including the effects of ATP-sensitive potassium current, lateralized connexins, and gap junction uncoupling. ATP-sensitive potassium channel (I KATP) opening is caused by ischemia, which can occur in diabetic or non-diabetic hearts. I KATP opening was simulated in this work to determine if the risk of ischemia-induced arrhythmias is affected by diabetes. Simulations were performed using healthy and diabetic models of rat and rabbit ventricle. Results showed that the diabetic rat model is less vulnerable to reentrant arrhythmia than the healthy rat model. The diabetic rabbit model was more vulnerable to reentrant arrhythmia than the healthy rabbit model. In both rabbit models, the vulnerability increased as the gap junctional coupling decreased. Opening of I KATP resulted in larger window of vulnerability. Conduction reserve was simulated based on 1D simulations for both rat and rabbit models. There was no difference between rat and rabbit conduction reserve. Our results showed that the simulation results are model-dependent, i.e., results from the rabbit model are similar to human clinical data, while the results from the rat model contradict human clinical observations, suggesting a significant species-dependence in arrhythmia vulnerability in the diabetic heart.
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Miranda-Perez ME, Ortega-Camarillo C, Del Carmen Escobar-Villanueva M, Blancas-Flores G, Alarcon-Aguilar FJ. Cucurbita ficifolia Bouché increases insulin secretion in RINm5F cells through an influx of Ca(2+) from the endoplasmic reticulum. J Ethnopharmacol 2016; 188:159-166. [PMID: 27174079 DOI: 10.1016/j.jep.2016.04.061] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 04/15/2016] [Accepted: 04/28/2016] [Indexed: 06/05/2023]
Abstract
ETHNOPHARMACOLOGICAL IMPORTANCE Cucurbita ficifolia Bouché(C. ficifolia) is a plant used in Mexican traditional medicine to control type 2 diabetes (T2D). The hypoglycemic effect of the fruit of C. ficifolia has been demonstrated in different experimental models and in T2D patients. It has been proposed that D-chiro-inositol (DCI) is the active compound of the fruit. Additionally, it has been reported that C. ficifolia increases the mRNA expression of insulin and Kir 6.2 (a component of the ATP-sensitive potassium (K(+)ATP) channel, which is activated by sulphonylurea) in RINm5F cells. However, it remains unclear whether C. ficifolia and DCI causes the secretion of insulin by increasing the concentration of intracellular calcium ([Ca(2+)]i) through K(+)ATP channel blockage or from the reservoir in the endoplasmic reticulum (ER). MATERIAL AND METHODS The aqueous extract of C. ficifolia was obtained and standardized with regard to its DCI content. RINm5F pancreatic β-cells were incubated with different concentrations (50, 100, 200 and 400μM) of DCI alone or C. ficifolia (9, 18, 36 and 72µg of extract/mL), and the [Ca(2+)]i of the cells was quantified. The cells were preloaded with the Ca(2+) fluorescent dye fluo4-acetoxymethyl ester (AM) and visualized by confocal microscopy. Insulin secretion was measured by an ELISA method. Subsequently, the effect of C. ficifolia on the K(+)ATP channel was evaluated. In this case, the blocker activator diazoxide was used to inhibit the C. ficifolia-induced calcium influx. In addition, the inositol 1,4,5-trisphosphate (IP3)-receptor-selective inhibitor 2-amino-thoxydiphenylborate (2-APB) was used to inhibit the influx of calcium from the ER that was induced by C. ficifolia. RESULTS It was found that DCI alone did not increase [Ca(2+)]i or insulin secretion. In contrast, treatment with C. ficifolia increased [Ca(2+)]i 10-fold compared with the control group. Insulin secretion increased by 46.9%. In the presence of diazoxide, C. ficifolia decreased [Ca(2+)]i by 50%, while insulin secretion increased by 36.4%. In contrast, in the presence of 2-APB, C. ficifolia increased [Ca(2+)]i 18-fold, while insulin secretion remained constant, indicating an additive effect. Therefore, C. ficifolia was not found to block the K(+)ATP channel. However, it did exert an effect by increasing [Ca(2+)]i from the ER, which may partly explain the insulin secretion observed following treatment with C. ficifolia. CONCLUSIONS The hypoglycemic properties of C. ficifolia can be explained in part by its effect as a secretagogue for insulin through an increase in [Ca(2+)]i from the calcium reservoir in the ER. Therefore, the mechanism of action of C. ficifolia is different to those of the currently used hypoglycemic drugs, such as sulfonylureas. These results support that C. ficifolia may be a potential natural resource for new agents to control T2D.
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Affiliation(s)
- Maria Elizabeth Miranda-Perez
- Division de Ciencia Biologicas y de la Salud (DCBS), Universidad Autonoma Metropolitana Unidad Iztapalapa (UAM-I), Avenida San Rafael Atlixco 186, Ciudad de Mexico, Mexico.
| | - Clara Ortega-Camarillo
- Unidad de Investigacion Medica en Bioquimica, HE, Centro Medico Nacional Siglo XXI. IMSS, Av. Cuauhtemoc 330, Col. Doctores, Del. Cuauhtemoc, Ciudad de Mexico, Mexico.
| | | | - Gerardo Blancas-Flores
- Laboratorio de Farmacología, Departamento de Ciencias de la Salud, DCBS, UAM-I, Avenida San Rafael Atlixco 186, Ciudad de Mexico, Mexico.
| | - Francisco Javier Alarcon-Aguilar
- Laboratorio de Farmacología, Departamento de Ciencias de la Salud, DCBS, UAM-I, Avenida San Rafael Atlixco 186, Ciudad de Mexico, Mexico.
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