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Lee SE, Kim DH, Son SM, Choi SY, You RY, Kim CH, Choi W, Kim HS, Lim YJ, Han JY, Kim HW, Yang IJ, Xu WX, Lee SJ, Kim YC, Yun HY. Physiological function and molecular composition of ATP-sensitive K + channels in human gastric smooth muscle. J Smooth Muscle Res 2020; 56:29-45. [PMID: 32581184 PMCID: PMC7324727 DOI: 10.1540/jsmr.56.29] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Gastric motility is controlled by slow waves. In general, the activation of the
ATP-sensitive K+ (KATP) channels in the smooth muscle
opposes the membrane excitability and produces relaxation. Since metabolic
inhibition and/or diabetes mellitus are accompanied by dysfunctions of gastric
smooth muscle, we examined the possible roles of KATP channels in
human gastric motility. We used human gastric corpus and antrum smooth muscle
preparations and recorded the mechanical activities with a conventional
contractile measuring system. We also identified the subunits of the
KATP channels using Western blot. Pinacidil (10 μM), a
KATP channel opener, suppressed contractions to 30% (basal tone
to −0.2 g) of the control. The inhibitory effect of pinacidil on contraction was
reversed to 59% of the control by glibenclamide (20 μM), a KATP
channel blocker. The relaxation by pinacidil was not affected by a pretreatment
with L-arginine methyl ester, tetraethylammonium, or 4-aminopyridine. Pinacidil
also inhibited the acetylcholine (ACh)-induced tonic and phasic contractions in
a glibenclamide-sensitive manner (42% and 6% of the control, respectively).
Other KATP channel openers such as diazoxide, cromakalim and
nicorandil also inhibited the spontaneous and ACh-induced contractions.
Calcitonin gene-related peptide (CGRP), a gastric neuropeptide, induced muscle
relaxation by the activation of KATP channels in human gastric smooth
muscle. Finally, we have found with Western blot studies, that human gastric
smooth muscle expressed KATP channels which were composed of Kir 6.2
and SUR2B subunits.
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Affiliation(s)
- Sang Eok Lee
- Department of Surgery, College of Medicine, Konyang University, 158 Gwanjeodong-ro, Seo-gu, Daejeon 35365, Korea
| | - Dae Hoon Kim
- Department of Surgery, College of Medicine, Chungbuk National University, Chungdae-ro 1, Seowon-gu, Cheongju, Chungbuk 28644, Korea
| | - Seung Myeung Son
- Department of Pathology, Chungbuk National University, Chungdae-ro 1, Seowon-gu, Cheongju, Chungbuk 28644, Korea
| | - Song-Yi Choi
- Department of Pathology, School of Medicine, Chungnam National University, Daejeon, Chungnam 35015, Korea
| | - Ra Young You
- Department of Physiology, College of Medicine, Chungbuk National University, Chungdae-ro 1, Seowon-gu, Cheongju, Chungbuk 28644, Korea
| | - Chan Hyung Kim
- Department of Pharmacology, College of Medicine, Chungbuk National University, Chungdae-ro 1, Seowon-gu, Cheongju, Chungbuk 28644, Korea
| | - Woong Choi
- Department of Pharmacology, College of Medicine, Chungbuk National University, Chungdae-ro 1, Seowon-gu, Cheongju, Chungbuk 28644, Korea
| | - Hun Sik Kim
- Department of Pharmacology, College of Medicine, Chungbuk National University, Chungdae-ro 1, Seowon-gu, Cheongju, Chungbuk 28644, Korea
| | - Yung Ji Lim
- College of Medicine, Chungbuk National University, Chungdae-ro 1, Seowon-gu, Cheongju, Chungbuk 28644, Korea
| | - Ji Young Han
- CheongDam I Plastic surgery, 21, Sinheung-ro 240, Uijeonbu-si, Gyronggido 11651, Korea
| | - Hyun Woo Kim
- College of Medicine, Chungbuk National University, Chungdae-ro 1, Seowon-gu, Cheongju, Chungbuk 28644, Korea
| | - In Jun Yang
- Department of Surgery, Seoul Nantional University Bundang Hospital, 166 Gumi-ro, Bundang-gu 13620, Seongnam, Korea
| | - Wen-Xie Xu
- Department of Physiology, College of Medcine, Shanghai Jiaotong University, 800 Dongchun Rd. Shanghai, 200240, P.R. China
| | - Sang Jin Lee
- Department of Physiology, College of Medicine, Chungbuk National University, Chungdae-ro 1, Seowon-gu, Cheongju, Chungbuk 28644, Korea
| | - Young Chul Kim
- Department of Physiology, College of Medicine, Chungbuk National University, Chungdae-ro 1, Seowon-gu, Cheongju, Chungbuk 28644, Korea
| | - Hyo-Yung Yun
- Department of Surgery, College of Medicine, Chungbuk National University, Chungdae-ro 1, Seowon-gu, Cheongju, Chungbuk 28644, Korea
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Lecea B, Gallego D, Farré R, Opazo A, Aulí M, Jiménez M, Clavé P. Regional functional specialization and inhibitory nitrergic and nonnitrergic coneurotransmission in the human esophagus. Am J Physiol Gastrointest Liver Physiol 2011; 300:G782-94. [PMID: 21330444 DOI: 10.1152/ajpgi.00514.2009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The aim of this study was to explore the myenteric mechanisms of control of human esophageal motility and the effect of nitrergic and nonnitrergic neurotransmitters. Human circular esophageal strips were studied in organ baths and with microelectrodes. Responses following electrical field stimulation (EFS) of enteric motoneurons (EMNs) or through nicotinic acetylcholine receptors were compared in the esophageal body (EB) and in clasp and sling regions in the lower esophageal sphincter (LES). In clasp LES strips: 1) sodium nitroprusside (1 nM to 100 μM), adenosine-5'-[β-thio]diphosphate trilithium salt (1-100 μM), and vasoactive intestinal peptide (1 nM to 1 μM) caused a relaxation; 2) 1 mM N(ω)-nitro-L-arginine (L-NNA) shifted the EFS "on"-relaxation to an "off"-relaxation, partly antagonized by 10 μM 2'-deoxy-N(6)-methyladenosine 3',5'-bisphosphate tetrasodium salt (MRS2179) or 10 U/ml α-chymotrypsin; and 3) nicotine-relaxation (100 μM) was mainly antagonized by L-NNA, and only partly by MRS2179 or α-chymotrypsin. In sling LES fibers, EFS and nicotine relaxation was abolished by L-NNA. In the EB, L-NNA blocked the latency period, and MRS2179 reduced "off"-contraction. The amplitude of cholinergic contraction decreased from the EB to both LES sides. EFS induced a monophasic inhibitory junction potential in clasp, sling, and EB fibers abolished by L-NNA. Our study shows a regional specialization to stimulation of EMNs in the human esophagus, with stronger inhibitory responses in clasp LES fibers and stronger cholinergic excitatory responses in the EB. Inhibitory responses are mainly triggered by nitrergic EMNs mediating the inhibitory junction potentials in the LES and EB, EFS on-relaxation in clasp and sling LES sides, and latency in the EB. We also found a minor role for purines (through P2Y(1) receptors) and vasoactive intestinal peptide-mediating part of nonnitrergic clasp LES relaxation.
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Affiliation(s)
- B Lecea
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, Instituto de Salud Carlos III, Mataró, Spain
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Regulation of basal tone, relaxation and contraction of the lower oesophageal sphincter. Relevance to drug discovery for oesophageal disorders. Br J Pharmacol 2007; 153:858-69. [PMID: 17994108 DOI: 10.1038/sj.bjp.0707572] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The lower oesophageal sphincter (LOS) is a specialized region of the oesophageal circular smooth muscle that allows the passage of a swallowed bolus to the stomach and prevents the reflux of gastric contents into the oesophagus. The anatomical arrangement of the LOS includes semicircular clasp fibres adjacent to the lesser gastric curvature and sling fibres following the greater gastric curvature. Such anatomical arrangement together with an asymmetric intrinsic innervation and distinct proportion of neurotransmitters in both regions produces an asymmetric pressure profile. The LOS tone is myogenic in origin and depends on smooth muscle properties that lead to opening of L-type Ca(2+) channels; however it can be modulated by enteric motor neurons, the parasympathetic and sympathetic extrinsic nervous system and several neurohumoral substances. Nitric oxide synthesized by neuronal NOS is the main inhibitory neurotransmitter involved in LOS relaxation. Different putative neurotransmitters have been proposed to play a role together with NO. So far, only ATP or related purines have shown to be co-transmitters with NO. Acetylcholine and tachykinins are involved in the LOS contraction acting through acetylcholine M(3) and tachykinin NK(2) receptors. Nitric oxide can also be involved in the regulation of LOS contraction. The understanding of the mechanisms that originate and modulate LOS tone, relaxation and contraction and the characterization of neurotransmitters and receptors involved in LOS function are important to develop new pharmacological tools to treat primary oesophageal motor disorders and gastro-oesophageal reflux disease.
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Park SY, Shin CY, Song HJ, Min YS, La Hyen O, Lee JW, Kim DY, Je HD, Sohn UD. Electrically stimulated relaxation is not mediated by GABA in cat lower esophageal sphincter muscle. Arch Pharm Res 2006; 29:400-4. [PMID: 16756085 DOI: 10.1007/bf02968590] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
This study examined the effect of Gamma-Amino butyric acid (GABA) and selective GABA receptor related drugs on the electrically stimulated relaxation in the lower esophageal sphincter muscle (LES) of a cat. Tetrodotoxin (10(-6) M) suppressed the electrically stimulated (0.5-5 Hz) relaxation of the LES. However, guanethidine (10(-6) M) and atropine (10(-6) M) had no effect indicating that the relaxations were neurally mediated via the nonadrenergic and noncholinergic (NANC) pathways. NG-nitro-L-arginine methyl ester (10(-4) M, L-NAME) also inhibited the relaxant response but did not completely abolish the electrically stimulated relaxation with 60 % inhibition, which suggests the involvement of nitric oxide as an inhibitory transmitter. This study examined the role of GABA, an inhibitory neurotransmitter, on neurally mediated LES relaxation. GABA (10(-3)-10(-5) M, non selective receptor agonist), muscimol (10(-3)-10(-5) M, GABA-A agonist), and baclofen (10(-3)-10(-5) M, GABA-B agonist) had no significant effect on the electrically stimulated relaxation. Moreover, bicuculline (10(-5) M, GABA-A antagonist) and phaclofen (10(-5) M, GABA-B antagonist) had no inhibitory effect on the electrically stimulated relaxation. This suggests that GABA and the GABA receptor are not involved in the electrically stimulated NANC relaxation in the cat LES.
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Affiliation(s)
- Sun Young Park
- Department of Pharmacology, College of Pharmacy, Chung Ang University, Seoul 156-756, Korea
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Farré R, Aulí M, Lecea B, Martínez E, Clavé P. Pharmacologic characterization of intrinsic mechanisms controlling tone and relaxation of porcine lower esophageal sphincter. J Pharmacol Exp Ther 2005; 316:1238-48. [PMID: 16303917 DOI: 10.1124/jpet.105.094482] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The neurotransmitters mediating relaxation of lower esophageal sphincter (LES) were studied using circular LES strips from adult pigs in organ baths. LES relaxation by sodium nitroprusside (1 nM-3 microM), vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating peptide (PACAP; 1 nM-1 microM), ATP (10 microM-30 mM), and tricarbonyldichlororuthenum dimer (1 microM-1 mM) was unaffected by tetrodotoxin (1 microM) or l-N(G)-nitroarginine methyl ester (l-NAME; 100 microM). Calcitonin gene-related peptide (CGRP; 1 nM-1 microM) did not affect LES tone. ATP relaxation was blocked by 1 microM apamin and the P2Y(1) antagonist MRS 2179 (N6-methyl 2'-deoxyadenosine 3',5'-bisphosphate; 10 microM). Apamin inhibited PACAP relaxation. VIP and PACAP relaxation was blocked by 10 U/ml alpha-chymotrypsin. L-NAME (-62.52 +/- 13.13%) and 1H-[1,2,4]oxadiazole-[4,3-alpha]quinoxalin-1-one (ODQ; 10 microM, -67.67 +/- 6.80%) similarly inhibited electrical LES relaxation, and apamin blocked non-nitrergic relaxation. Nicotine relaxation (100 microM) was inhibited by L-NAME (-60.37 +/- 10.8%) and ODQ (-41.90 +/- 7.89%), and apamin also blocked non-nitrergic relaxation. Non-nitrergic and apamin-sensitive LES relaxation by electrical stimulation or nicotine was strongly inhibited by MRS 2179, slightly inhibited by alpha-chymotrypsin and the P2X(1,2,3) receptor antagonist NF 279 (8,8 cent-[carbonylbis(imino-4,1-phenylenecarbonylimino-4,1-phenylenecarbonylimino)]bis-1,3,5-naphthalenetrisulfonic acid hexasodium salt; 10 microM), and unaffected by tin protoporphyrin IX (100 microM). Porcine LES relaxation after stimulation of intrinsic inhibitory motor neurons is mediated by two main neuromuscular pathways: nitric oxide through guanylate cyclase signaling and apamin-insensitive mechanisms and by non-nitrergic apamin-sensitive neurotransmission mainly mediated by ATP, ADP, or a related purine acting on P2Y1 receptors and a minor contribution of purinergic P2X1,2,3 receptors and PACAP. Nitrergic and purinergic co-transmitters show parallel effects of similar magnitude without major interplay. Our study shows no role for CGRP and only a minor one for VIP and carbon monoxide in porcine LES relaxation.
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Affiliation(s)
- Ricard Farré
- Fundació de Gastroenterologia Dr. Francisco Vilardell, Barcelona, Spain
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Zhang Y, Paterson WG. Nitric oxide contracts longitudinal smooth muscle of opossum oesophagus via excitation-contraction coupling. J Physiol 2001; 536:133-40. [PMID: 11579163 PMCID: PMC2278847 DOI: 10.1111/j.1469-7793.2001.00133.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
1. The effects of sodium nitroprusside (SNP) and diethylenetriamine/nitric oxide adduct (DETA/NO), putative nitric oxide (NO) donors, on opossum oesophageal longitudinal smooth muscle were investigated using isometric tension and intracellular micro-electrode recordings. 2. SNP produced concentration-dependent contractions of oesophageal longitudinal smooth muscle with an EC(50) of 239.6 +/- 78.2 microM (mean +/- S.E.M., n = 10). Maximal contraction induced by SNP (1 mM) was about 75.5 +/- 8.5 % (n = 10) of the 60 mM KCl-induced contraction. The SNP-induced contraction was resistant to tetrodotoxin (TTX; 1 microM), but abolished by nifedipine (1 microM), as well as by niflumic acid (300 microM) and 9-anthroic acid (9-AC; 1 mM), Ca(2+)-activated Cl(-) channel blockers. 3. DETA/NO at concentrations of 100 and 500 microM induced 83.1 +/- 24.4 and 104.1 +/- 34.9 % of the 60 mM KCl-induced contraction (n = 4), respectively, which was abolished by nifedipine (1 microM), niflumic acid (300 microM) and 9-AC (1 mM). 4. Pre-application of 1H-[1,2,4]oxidiazolo[4,3,-alpha]quinoxalin-1-one (ODQ) (10 microM), a guanylate cyclase inhibitor, significantly inhibited the SNP-induced contraction, whereas 8-bromo-cGMP (1 mM), a membrane-permeable analogue of cGMP, mimicked the SNP-induced contraction. 5. Intracellular recordings revealed that SNP (300 microM) depolarized resting membrane potentials (RMPs) and increased the frequency of spontaneous spike-like action potentials. However, these electrical alterations were eliminated by pretreatment with niflumic acid (300 microM). 6. These results suggest that NO produces an excitation-contraction coupling in opossum oesophageal longitudinal smooth muscle via a cGMP-dependent signalling pathway. This contraction depends on extracellular Ca(2+) entry through activation of L-type Ca(2+) channels.
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Affiliation(s)
- Y Zhang
- Gastrointestinal Disease Research Unit and Departments of Medicine and Physiology, Queen's University, Kingston, Ontario, Canada K7L 5G2
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Abstract
Swallowing is a complex mechanism based on the coordinated collaboration of tongue, pharynx and esophagus. Disturbances of this interplay or disorders of one or several of these components lead to dysphagia, non-cardiac chest pain or regurgitation. The major primary esophageal motility disorders--achalasia, diffuse esophageal spasm, hypercontractile esophagus ('nutcracker esophagus') and non-specific motility disorder--are of unknown etiology. Other esophageal diseases, such as cervical diverticula or gastroesophageal reflux disease, might also be caused by a primary esophageal motility disorder. Medical treatment of esophageal disorders with esophageal hyper- or dysmotility requires agents that reduce esophageal contractile force (anticholinergic agents, nitrates, calcium antagonists). Despite the beneficial effect of the various drugs on esophageal motility parameters, the clinical benefit of medical treatment of esophageal motility disorders is rather disappointing. Calcium channel antagonist, alone or in combination with anticholinergics or nitrates, can be used as a medical trial, especially in mild achalasia. However, medical therapy is clearly inferior to pneumatic balloon dilation therapy. Recently, botulinum toxin injection was suggested as a therapeutic option in achalasia patients with good results on lower esophageal sphincter pressure (LESP) and symptom scores that were similar to the results achieved by pneumatic balloon dilation. Hypercontractile esophagus shows a good manometric response to calcium channel antagonists, but only little clinical effect in terms of improvement of symptoms. Diffuse esophageal spasm is a relatively rare disease and few clinical studies are available. The use of calcium channel antagonists can be beneficial, at least in some patients with diffuse esophageal spasm. From clinical and epidemiological studies, there is some evidence of a 'psychological' component in the pathogenesis or perception of esophageal symptoms. There is some clinical benefit from centrally acting drugs such as benzodiazepines or antidepressants. With the exception of botulinum toxin for achalasia, medical therapy of primary esophageal motility disorders is rather limited and the clinical results are poor. Further understanding of esophageal pathophysiology as well as development of new receptor-selective drugs might increase our chances of a successful treatment of primary esophageal motility disorders.
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Affiliation(s)
- M Storr
- Department of Internal Medicine II, Technical University of Munich, Germany
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Uc A, Oh ST, Murray JA, Clark E, Conklin JL. Biphasic relaxation of the opossum lower esophageal sphincter: roles of NO., VIP, and CGRP. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:G548-54. [PMID: 10484379 DOI: 10.1152/ajpgi.1999.277.3.g548] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Vasoactive intestinal polypeptide (VIP) and nitric oxide (NO.) are thought to mediate lower esophageal sphincter (LES) relaxation. Transverse muscle strips from the opossum LES were used to test this hypothesis. Electrical field stimulation (EFS) produced a biphasic LES relaxation: a rapid component during the stimulus was more prominent at lower stimulus frequencies, and a sustained component was more prominent at higher frequencies. N(omega)-nitro-L-arginine and hemoglobin inhibited the rapid component but affected the sustained component less. Exogenous VIP decreased LES tone. A number of purported VIP antagonists blocked neither VIP-induced nor EFS-induced relaxation of the LES. The calcitonin gene-related peptide (CGRP) antagonist CGRP-(8-37) did not alter EFS-induced LES relaxation. EFS-induced relaxation of opossum LES muscle is biphasic, and the initial, rapid component of the relaxation is mediated primarily by NO. The mediator of the sustained component was not identified.
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Affiliation(s)
- A Uc
- Department of Pediatrics, University of Iowa College of Medicine and Department of Veterans Affairs Medical Center, Iowa City, Iowa 52242, USA
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