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Saeki T, Kimura T, Hashidume K, Murayama T, Yamamura H, Ohya S, Suzuki Y, Nakayama S, Imaizumi Y. Conversion of Ca2+ oscillation into propagative electrical signals by Ca2+-activated ion channels and connexin as a reconstituted Ca2+ clock model for the pacemaker activity. Biochem Biophys Res Commun 2019; 510:242-247. [DOI: 10.1016/j.bbrc.2019.01.080] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 01/16/2019] [Indexed: 01/27/2023]
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Kim D, Kim JN, Nam JH, Lee JR, Kim SC, Kim BJ. Modulation of Pacemaker Potentials in Murine Small Intestinal Interstitial Cells of Cajal by Gamisoyo-San, a Traditional Chinese Herbal Medicine. Digestion 2018; 98:56-68. [PMID: 29672308 DOI: 10.1159/000487186] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 01/22/2018] [Indexed: 02/04/2023]
Abstract
BACKGROUND The Gamisoyo-san (GSS) has been used for -improving the gastrointestinal (GI) symptoms. The purpose of this study was to investigate the effects of GSS, a traditional Chinese herbal medicine, on the pacemaker potentials of mouse small intestinal interstitial cells of Cajal (ICCs). METHODS ICCs from the small intestines were dissociated and cultured. Whole-cell patch-clamp configuration was used to record pacemaker potentials and membrane currents. RESULTS GSS depolarized ICC pacemaker potentials in a dose-dependent manner. Pretreatment with 4-diphenylacetoxypiperidinium iodide completely inhibited GSS-induced pacemaker potential depolarizations. Intracellular GDP-β-S inhibited GSS-induced effects, and in the presence of U-73122, GSS-induced effects were inhibited. Also, GSS in the presence of a Ca2+-free solution or thapsigargin did not depolarize pacemaker potentials. However, in the presence of calphostin C, GSS slightly depolarized pacemaker potentials. Furthermore, GSS inhibited both transient receptor potential melastatin7 and Ca2+-activated Cl- channel (anoctamin1) currents. CONCLUSION GSS depolarized pacemaker potentials of ICCs via G protein and muscarinic M3 receptor signaling pathways and through internal or external Ca2+-, phospholipase C-, and protein kinase C-dependent and transient receptor potential melastatin 7-, and anoctamin 1-independent pathways. The study shows that GSS may regulate GI tract motility, suggesting that GSS could be a basis for developing novel prokinetic agents for treating GI motility dysfunctions.
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Affiliation(s)
- Doeun Kim
- Division of Longevity and Biofunctional Medicine, Yangsan, Republic of Korea
| | - Jung Nam Kim
- Division of Longevity and Biofunctional Medicine, Yangsan, Republic of Korea.,Healthy Aging Korean Medical Research Center (HAKMRC), Pusan National University School of Korean Medicine, Yangsan, Republic of Korea
| | - Joo Hyun Nam
- Department of Physiology, College of Medicine, Dongguk University, Kyungju, Republic of Korea
| | - Jong Rok Lee
- Department of Pharmaceutical Engineering, Daegu Haany University, Gyeongsan, Republic of Korea
| | - Sang Chan Kim
- College of Oriental Medicine, Daegu Haany University, Gyeongsan, Republic of Korea
| | - Byung Joo Kim
- Division of Longevity and Biofunctional Medicine, Yangsan, Republic of Korea.,Healthy Aging Korean Medical Research Center (HAKMRC), Pusan National University School of Korean Medicine, Yangsan, Republic of Korea
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Currò D. The Modulation of Potassium Channels in the Smooth Muscle as a Therapeutic Strategy for Disorders of the Gastrointestinal Tract. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2016; 104:263-305. [PMID: 27038377 DOI: 10.1016/bs.apcsb.2015.12.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Alterations of smooth muscle contractility contribute to the pathophysiology of important functional gastrointestinal disorders (FGIDs) such as functional dyspepsia and irritable bowel syndrome. Consequently, drugs that decrease smooth muscle contractility are effective treatments for these diseases. Smooth muscle contraction is mainly triggered by Ca(2+) influx through voltage-dependent channels located in the plasma membrane. Thus, the modulation of the membrane potential results in the regulation of Ca(2+) influx and cytosolic levels. K(+) channels play fundamental roles in these processes. The open probability of K(+) channels increases in response to various stimuli, including membrane depolarization (voltage-gated K(+) [K(V)] channels) and the increase in cytosolic Ca(2+) levels (Ca(2+)-dependent K(+) [K(Ca)] channels). K(+) channel activation is mostly associated with outward K(+) currents that hyperpolarize the membrane and reduce cell excitability and contractility. In addition, some K(+) channels are open at the resting membrane potential values of the smooth muscle cells in some gut segments and contribute to set the resting membrane potential itself. The closure of these channels induces membrane depolarization and smooth muscle contraction. K(V)1.2, 1.5, 2.2, 4.3, 7.4 and 11.1, K(Ca)1.1 and 2.3, and inwardly rectifying type 6K(+) (K(ir)6) channels play the most important functional roles in the gastrointestinal smooth muscle. Activators of all these channels may theoretically relax the gastrointestinal smooth muscle and could therefore be promising new therapeutic options for FGID. The challenge of future drug research and development in this area will be to synthesize molecules selective for the channel assemblies expressed in the gastrointestinal smooth muscle.
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Affiliation(s)
- Diego Currò
- Institute of Pharmacology, School of Medicine, Catholic University of the Sacred Heart, Rome, Italy.
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Kito Y, Mitsui R, Ward SM, Sanders KM. Characterization of slow waves generated by myenteric interstitial cells of Cajal of the rabbit small intestine. Am J Physiol Gastrointest Liver Physiol 2015; 308:G378-88. [PMID: 25540230 PMCID: PMC4346752 DOI: 10.1152/ajpgi.00308.2014] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Slow waves (slow wavesICC) were recorded from myenteric interstitial cells of Cajal (ICC-MY) in situ in the rabbit small intestine, and their properties were compared with those of mouse small intestine. Rabbit slow wavesICC consisted of an upstroke depolarization followed by a distinct plateau component. Ni(2+) and nominally Ca(2+)-free solutions reduced the rate-of-rise and amplitude of the upstroke depolarization. Replacement of Ca(2+) with Sr(2+) enhanced the upstroke component but decreased the plateau component of rabbit slow wavesICC. In contrast, replacing Ca(2+) with Sr(2+) decreased both components of mouse slow wavesICC. The plateau component of rabbit slow wavesICC was inhibited in low-extracellular-Cl(-)-concentration (low-[Cl(-)]o) solutions and by 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), an inhibitor of Cl(-) channels, cyclopiazonic acid (CPA), an inhibitor of internal Ca(2+) pumps, or bumetanide, an inhibitor of Na(+)-K(+)-2Cl(-) cotransporter (NKCC1). Bumetanide also inhibited the plateau component of mouse slow wavesICC. NKCC1-like immunoreactivity was observed mainly in ICC-MY in the rabbit small intestine. Membrane depolarization with a high-K(+) solution reduced the upstroke component of rabbit slow wavesICC. In cells depolarized with elevated external K(+), DIDS, CPA, and bumetanide blocked slow wavesICC. These results suggest that the upstroke component of rabbit slow wavesICC is partially mediated by voltage-dependent Ca(2+) influx, whereas the plateau component is dependent on Ca(2+)-activated Cl(-) efflux. NKCC1 is likely to be responsible for Cl(-) accumulation in ICC-MY. The results also suggest that the mechanism of the upstroke component differs in rabbit and mouse slow wavesICC in the small intestine.
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Affiliation(s)
- Yoshihiko Kito
- Department of Pharmacology, Faculty of Medicine, Saga University, Nabeshima, Saga, Japan; Department of Cell Physiology, Nagoya City University Medical School, Mizuho-ku, Nagoya, Japan; and
| | - Retsu Mitsui
- 2Department of Cell Physiology, Nagoya City University Medical School, Mizuho-ku, Nagoya, Japan; and
| | - Sean M. Ward
- 3Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
| | - Kenton M. Sanders
- 3Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
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Liu DH, Huang X, Meng XM, Zhang CM, Lu HL, Kim YC, Xu WX. Exogenous H2 S enhances mice gastric smooth muscle tension through S-sulfhydration of KV 4.3, mediating the inhibition of the voltage-dependent potassium current. Neurogastroenterol Motil 2014; 26:1705-16. [PMID: 25292410 DOI: 10.1111/nmo.12451] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 09/12/2014] [Indexed: 12/30/2022]
Abstract
BACKGROUND Hydrogen sulfide (H2 S) has been shown to have an excitatory effect on gastric motility, but the underlying molecular mechanism is unclear. In this study, we aimed to investigate the possible targets of H2 S and determine how H2 S affects its target proteins during H2 S-induced contraction. METHODS Patch-clamp and potentiometric fluorescence dye were utilized to measure the electrophysiological changes. The Biotin-switch assay was utilized to detect the protein S-sulfhydration. The isometric tension measurement was conducted too. KEY RESULTS Exogenous H2 S enhanced the tonic contraction of gastric antral smooth muscle, and voltage-dependent potassium channel (KV ) blocker and Dithiothreitol (DTT, a reducing agent) abolished the excitatory effect of NaHS. Exogenous H2 S inhibited the fast inactivation component of the voltage-dependent potassium channel current (IKVfast ) in isolated gastric antral smooth muscle cells. H2 S inhibited the KV 4.3 current in H293 cells with heterologous expression of KV 4.3, but did not inhibit the KV 4.1 and KV 4.2 currents, which together contribute greatly to IKVfast . NaHS significantly decreased the membrane potential in cultured gastric smooth muscle cells, but the NaHS-induced depolarization was suppressed by knockdown of KV 4.3 and N-ethylamaleimide (NEM), a free thiol group blocker. In addition, NaHS sulfhydrated KV 4.3 in H293 cells and in gastric smooth muscle tissue. However, this S-sulfhydration was inhibited by NEM and DTT. Meanwhile the NaHS-induced inhibition of IKVfast and KV 4.3 was also blocked by NEM and DTT. CONCLUSIONS & INFERENCES These results suggest that exogenous H2 S sulfhydrates KV 4.3 to decrease the membrane potential, thereby enhancing the basal tension of gastric antral smooth muscle.
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Affiliation(s)
- D-H Liu
- Department of Physiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
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Kito Y, Kurahashi M, Mitsui R, Ward SM, Sanders KM. Spontaneous transient hyperpolarizations in the rabbit small intestine. J Physiol 2014; 592:4733-45. [PMID: 25217377 DOI: 10.1113/jphysiol.2014.276337] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Four types of electrical activity were recorded and related to cell structure by intracellular recording and dye injection into impaled cells in muscles of rabbit small intestine. The specific cell types from which recordings were made were longitudinal smooth muscle cells (LSMCs), circular smooth muscle cells (CSMCs), interstitial cells of Cajal distributed in the myenteric region (ICC-MY) and fibroblast-like cells (FLCs). Slow waves (slow wavesSMC) were recorded from LSMCs and CSMCs. Slow waves (slow wavesICC) were of greatest amplitude (>50 mV) and highest maximum rate of rise (>10 V s(-1)) in ICC-MY. The dominant activity in FLCs was spontaneous transient hyperpolarizations (STHs), with maximum amplitudes above 30 mV. STHs were often superimposed upon small amplitude slow waves (slow wavesFLC). STHs displayed a cyclical pattern of discharge irrespective of background slow wave activity. STHs were inhibited by MRS2500 (3 μm), a P2Y1 antagonist, and abolished by apamin (0.3 μm), a blocker of small conductance Ca(2+)-activated K(+) channels. Small amplitude STHs (<15 mV) were detected in smooth muscle layers, whereas STHs were not resolved in cells identified as ICC-MY. Electrical field stimulation evoked purinergic inhibitory junction potentials (IJPs) in CSMCs. Purinergic IJPs were not recorded from ICC-MY. These results suggest that FLCs may regulate smooth muscle excitability in the rabbit small intestine via generation of rhythmic apamin-sensitive STHs. Stimulation of P2Y1 receptors modulates the amplitudes of STHs. Our results also suggest that purinergic inhibitory motor neurons regulate the motility of the rabbit small intestine by causing IJPs in FLCs that conduct to CSMCs.
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Affiliation(s)
- Yoshihiko Kito
- Department of Pharmacology, Faculty of Medicine, Saga University, Nabeshima, Saga, 849-8501, Japan Department of Cell Physiology, Nagoya City University Medical School, Mizuho-ku, Nagoya, 467-8601, Japan
| | - Masaaki Kurahashi
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV, 89557, USA
| | - Retsu Mitsui
- Department of Cell Physiology, Nagoya City University Medical School, Mizuho-ku, Nagoya, 467-8601, Japan
| | - Sean M Ward
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV, 89557, USA
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV, 89557, USA
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Liu DH, Huang X, Guo X, Meng XM, Wu YS, Lu HL, Zhang CM, Kim YC, Xu WX. Voltage dependent potassium channel remodeling in murine intestinal smooth muscle hypertrophy induced by partial obstruction. PLoS One 2014; 9:e86109. [PMID: 24516526 PMCID: PMC3916336 DOI: 10.1371/journal.pone.0086109] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 12/05/2013] [Indexed: 11/18/2022] Open
Abstract
Partial obstruction of the small intestine causes obvious hypertrophy of smooth muscle cells and motility disorder in the bowel proximate to the obstruction. To identify electric remodeling of hypertrophic smooth muscles in partially obstructed murine small intestine, the patch-clamp and intracellular microelectrode recording methods were used to identify the possible electric remodeling and Western blot, immunofluorescence and immunoprecipitation were utilized to examine the channel protein expression and phosphorylation level changes in this research. After 14 days of obstruction, partial obstruction caused obvious smooth muscle hypertrophy in the proximally located intestine. The slow waves of intestinal smooth muscles in the dilated region were significantly suppressed, their amplitude and frequency were reduced, whilst the resting membrane potentials were depolarized compared with normal and sham animals. The current density of voltage dependent potassium channel (KV) was significantly decreased in the hypertrophic smooth muscle cells and the voltage sensitivity of KV activation was altered. The sensitivity of KV currents (IKV) to TEA, a nonselective potassium channel blocker, increased significantly, but the sensitivity of IKv to 4-AP, a KV blocker, stays the same. The protein levels of KV4.3 and KV2.2 were up-regulated in the hypertrophic smooth muscle cell membrane. The serine and threonine phosphorylation levels of KV4.3 and KV2.2 were significantly increased in the hypertrophic smooth muscle cells. Thus this study represents the first identification of KV channel remodeling in murine small intestinal smooth muscle hypertrophy induced by partial obstruction. The enhanced phosphorylations of KV4.3 and KV2.2 may be involved in this process.
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Affiliation(s)
- Dong-Hai Liu
- Department of Physiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Xu Huang
- Department of Physiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Xin Guo
- Department of Physiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Xiang-Min Meng
- Department of Physiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yi-Song Wu
- Department of Physiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Hong-Li Lu
- Department of Physiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Chun-Mei Zhang
- Department of Physiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Young-chul Kim
- Department of Physiology, Chungbuk National University College of Medicine, Cheongju, Chungbuk, Republic of Korea
| | - Wen-Xie Xu
- Department of Physiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
- * E-mail:
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Kito Y, Suzuki H. Properties of Rikkunshi-to (TJ-43)-induced relaxation of rat gastric fundus smooth muscles. Am J Physiol Gastrointest Liver Physiol 2010; 298:G755-63. [PMID: 20167876 DOI: 10.1152/ajpgi.00333.2009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The relaxant effects of Rikkunshi-to (TJ-43), a gastroprotective herbal medicine, on rat gastric fundus were investigated. Experiments were carried out using standard tension and intracellular microelectrode recording techniques. During contraction induced by enprostil (0.5 microM), a prostaglandin E(2) analog, TJ-43, produced relaxation dose dependently (0.1-5.0 mg/ml) in the rat fundic circular smooth muscle (CSM) strips. The relaxant effects of TJ-43 were not affected by tetrodotoxin or 1 H[1, 2, 4] oxadiazolo [4, 3-a] quinoxalin-1-one (10 microM), an inhibitor of soluble guanylate cyclase. TJ-43 inhibited enprostil-induced membrane depolarization. Apamin (1 microM), a blocker of small-conductance Ca(2+)-activated K(+) (SK) channel, inhibited T-43-induced membrane repolarization. TJ-43-induced relaxation was biphasic, comprising of an initial fast followed by a second slow relaxation. The fast relaxation was abolished by apamin. Application of high K(+) (29.4 mM [K(+)](o)) also abolished the fast relaxation induced by TJ-43. In diabetic Goto-Kakizaki (GK) rat fundic CSM strips, the relaxant responses of TJ-43 during enprostil-induced contraction were increased compared with control rat strips. These results indicate that TJ-43 elicited fast muscle relaxation through membrane hyperpolarization induced by the activation of SK channels; the time-dependent slow relaxation reflects an additional direct of TJ-43 on CSM in the rat gastric fundus. Because TJ-43-evoked relaxation of fundic CSM strips was more potent in diabetic GK rat than in control rat, further analysis of this herb could lead to better treatments of diabetic gastroparesis.
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Affiliation(s)
- Yoshihiko Kito
- Dept. of Physiology, Nagoya City Univ. Medical School, Mizuho-ku, Nagoya, Japan.
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Abstract
Interstitial cells of Cajal (ICC) are the pacemakers of the gut, initiating slow-wave activity. Several ion channels have been identified that contribute to the depolarization phase of the slow wave. Our aim was to contribute to knowledge about the identity and role of ICC potassium channels in pacemaking. Here we describe a transient outward potassium current in cell-attached patches of ICC. This current was activated almost instantaneously at potentials positive of the resting membrane potential and inactivated as a single exponential or biexponential with time constants that varied widely from patch to patch. Averaged traces gave a biexponential inactivation with time constants of approximately 40 and approximately 500 ms, with no clear voltage dependence. Analysis of single-channel openings and closings indicated a channel conductance of 5 pS and permeability sequence of K(+) (111) > Na(+) (1) > N-methyl-d-glucamine(+) (0.11). The current was completely blocked by 20 microM clotrimazole but was unaffected by 20 microM ketoconazole, 10 microM E4031, or 20 microM clofilium; 5 mM 4-aminopyridine slowed the activation of the current. The transient outward current may be important in moderating the upstroke of the pacemaker potential.
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Affiliation(s)
- Sean P Parsons
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
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