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Kim JN, Kim BJ. Depolarization of pacemaker potentials by caffeic acid phenethyl ester in interstitial cells of Cajal from the murine small intestine. Can J Physiol Pharmacol 2019; 98:201-210. [PMID: 31689119 DOI: 10.1139/cjpp-2019-0452] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Interstitial cells of Cajal (ICCs) are pacemaker cells in the gastrointestinal (GI) tract and generate pacemaker potentials. In this study, we investigated the effects of caffeic acid phenethyl ester (CAPE) on the pacemaker potentials of ICCs from the mouse small or large intestine. Using the whole-cell patch-clamp configuration, we found that CAPE depolarized the pacemaker potentials of cultured ICCs from the murine small intestine in a dose-dependent manner. The estrogen receptor (ER) β antagonist PHTPP completely inhibited CAPE-induced depolarization, but the ERα antagonist BHPI did not. Intracellular GDP-β-S and pretreatment with Ca2+-free solution or thapsigargin also blocked CAPE-induced depolarization. To investigate the mechanisms of CAPE-mediated depolarization of ICCs, we used the nonselective cation channel (NSCC) inhibitor flufenamic acid, the Cl- channel blocker, mitogen-activated protein kinase (MAPK) inhibitors PD98059, SB203580, or SP600125, and PI3 kinase inhibitor LY294002. All inhibitors blocked the CAPE-induced pacemaker potential depolarization of ICCs. These results suggest that CAPE induces pacemaker potential depolarization through ERβ in a G protein, NSCC, Cl- channel, MAPK- and PI3 kinase dependent manner via intracellular and extracellular Ca2+ regulation in the murine small intestine. CAPE may therefore modulate GI motility by acting on ICCs in the murine small intestine.
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Affiliation(s)
- Jeong Nam Kim
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan 50612, Republic of Korea.,Healthy Aging Korean Medical Research Center, Pusan National University School of Korean Medicine, Yangsan 50612, Republic of Korea
| | - Byung Joo Kim
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan 50612, Republic of Korea.,Healthy Aging Korean Medical Research Center, Pusan National University School of Korean Medicine, Yangsan 50612, Republic of Korea
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Kim JN, Kim BJ. The Mechanism of Action of Ghrelin and Motilin in the Pacemaker Potentials of Interstitial Cells of Cajal from the Murine Small Intestine. Mol Cells 2019; 42:470-479. [PMID: 31250620 PMCID: PMC6602145 DOI: 10.14348/molcells.2019.0028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 04/26/2019] [Accepted: 05/07/2019] [Indexed: 02/07/2023] Open
Abstract
Interstitial cells of Cajal (ICCs) are pacemaker cells that exhibit periodic spontaneous depolarization in the gastrointestinal (GI) tract and generate pacemaker potentials. In this study, we investigated the effects of ghrelin and motilin on the pacemaker potentials of ICCs isolated from the mouse small intestine. Using the whole-cell patch-clamp configuration, we demonstrated that ghrelin depolarized pacemaker potentials of cultured ICCs in a dose-dependent manner. The ghrelin receptor antagonist [D-Lys] GHRP-6 completely inhibited this ghrelin-induced depolarization. Intracellular guanosine 5'-diphosphate-β-S and pre-treatment with Ca2+free solution or thapsigargin also blocked the ghrelin-induced depolarization. To investigate the involvement of inositol triphosphate (IP3), Rho kinase, and protein kinase C (PKC) in ghrelin-mediated pacemaker potential depolarization of ICCs, we used the IP3 receptor inhibitors 2-aminoethoxydiphenyl borate and xestospongin C, the Rho kinase inhibitor Y-27632, and the PKC inhibitors staurosporine, Go6976, and rottlerin. All inhibitors except rottlerin blocked the ghrelin-induced pacemaker potential depolarization of ICCs. In addition, motilin depolarized the pacemaker potentials of ICCs in a similar dose-dependent manner as ghrelin, and this was also completely inhibited by [D-Lys] GHRP-6. These results suggest that ghrelin induced the pacemaker potential depolarization through the ghrelin receptor in a G protein-, IP3-, Rho kinase-, and PKC-dependent manner via intracellular and extracellular Ca2+ regulation. In addition, motilin was able to depolarize the pacemaker potentials of ICCs through the ghrelin receptor. Therefore, ghrelin and its receptor may modulate GI motility by acting on ICCs in the murine small intestine.
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Affiliation(s)
- Jeong Nam Kim
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan 50612,
Korea
- Healthy Aging Korean Medical Research Center, Pusan National University School of Korean Medicine, Yangsan 50612,
Korea
| | - Byung Joo Kim
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan 50612,
Korea
- Healthy Aging Korean Medical Research Center, Pusan National University School of Korean Medicine, Yangsan 50612,
Korea
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ATP-sensitive K + channels maintain resting membrane potential in interstitial cells of Cajal from the mouse colon. Eur J Pharmacol 2017; 809:98-104. [PMID: 28511870 DOI: 10.1016/j.ejphar.2017.05.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 05/12/2017] [Accepted: 05/12/2017] [Indexed: 11/20/2022]
Abstract
To investigate the role of ATP-sensitive K+(KATP) channels on pacemaker activity in interstitial cells of Cajal (ICC), whole-cell patch clamping, RT-PCR, and intracellular Ca2+([Ca2+]i) imaging were performed in cultured colonic ICC. Pinacidil (a K+ channel opener) hyperpolarized the membrane and inhibited the generation of pacemaker potential, and this effect was reversed by glibenclamide (a KATP channel blocker). RT-PCR showed that Kir 6.1 and SUR2B were expressed in Ano-1 positive colonic ICC. Glibenclamide depolarized the membrane and increased pacemaker potential frequency. However, 5-hydroxydecanoic acid (a mitochondrial KATP channel blocker) had no effects on pacemaker potentials. Phorbol 12-myristate 13-acetate (PMA; a protein kinase C activator) blocked the pinacidil-induced effects, and PMA alone depolarized the membrane and increased pacemaker potential frequency. Cell-permeable 8-bromo-cyclic AMP also increased pacemaker potential frequency. Recordings of spontaneous intracellular Ca2+([Ca2+]i) oscillations showed that glibenclamide increased the frequency of [Ca2+]i oscillations. In small intestinal ICC, glibenclamide alone did not alter the generation of pacemaker potentials, and Kir 6.2 and SUR2B were expressed in Ano-1 positive ICC. Therefore, KATP channels in colonic ICC are activated in resting state and play an important role in maintaining resting membrane potential.
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Wu MJ, Kee KH, Na J, Kim SW, Bae Y, Shin DH, Choi S, Jun JY, Jeong HS, Park JS. Pituitary Adenylate Cyclase-activating Polypeptide Inhibits Pacemaker Activity of Colonic Interstitial Cells of Cajal. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2015; 19:435-40. [PMID: 26330756 PMCID: PMC4553403 DOI: 10.4196/kjpp.2015.19.5.435] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 04/13/2015] [Accepted: 04/30/2015] [Indexed: 01/19/2023]
Abstract
This study aimed to investigate the effect of pituitary adenylate cyclase-activating peptide (PACAP) on the pacemaker activity of interstitial cells of Cajal (ICC) in mouse colon and to identify the underlying mechanisms of PACAP action. Spontaneous pacemaker activity of colonic ICC and the effects of PACAP were studied using electrophysiological recordings. Exogenously applied PACAP induced hyperpolarization of the cell membrane and inhibited pacemaker frequency in a dose-dependent manner (from 0.1 nM to 100 nM). To investigate cyclic AMP (cAMP) involvement in the effects of PACAP on ICC, SQ-22536 (an inhibitor of adenylate cyclase) and cell-permeable 8-bromo-cAMP were used. SQ-22536 decreased the frequency of pacemaker potentials, and cell-permeable 8-bromo-cAMP increased the frequency of pacemaker potentials. The effects of SQ-22536 on pacemaker potential frequency and membrane hyperpolarization were rescued by co-treatment with glibenclamide (an ATP-sensitive K(+) channel blocker). However, neither N (G)-nitro-L-arginine methyl ester (L-NAME, a competitive inhibitor of NO synthase) nor 1H-[1,2,4]oxadiazolo[4,3-α]quinoxalin-1-one (ODQ, an inhibitor of guanylate cyclase) had any effect on PACAP-induced activity. In conclusion, this study describes the effects of PACAP on ICC in the mouse colon. PACAP inhibited the pacemaker activity of ICC by acting through ATP-sensitive K(+) channels. These results provide evidence of a physiological role for PACAP in regulating gastrointestinal (GI) motility through the modulation of ICC activity.
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Affiliation(s)
- Mei Jin Wu
- Department of Physiology, Chonnam National University Medical School, Gwangju 501-757, Korea
| | - Keun Hong Kee
- Department of Pathology, College of Medicine, Chosun University, Gwangju 501-759, Korea
| | - Jisun Na
- Department of Internal Medicine, College of Medicine, Chosun University, Gwangju 501-759, Korea
| | - Seok Won Kim
- Department of Internal Medicine, College of Medicine, Chosun University, Gwangju 501-759, Korea
| | - Youin Bae
- Department of Dermatology, Hallym University Dongtan Sacred Heart Hospital, Hwaseong 445-907, Korea
| | - Dong Hoon Shin
- Department of Physiology, College of Medicine, Chosun University, Gwangju 501-759, Korea
| | - Seok Choi
- Department of Physiology, College of Medicine, Chosun University, Gwangju 501-759, Korea
| | - Jae Yeoul Jun
- Department of Physiology, College of Medicine, Chosun University, Gwangju 501-759, Korea
| | - Han-Seong Jeong
- Department of Physiology, Chonnam National University Medical School, Gwangju 501-757, Korea
| | - Jong-Seong Park
- Department of Physiology, Chonnam National University Medical School, Gwangju 501-757, Korea
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Lee S, Gim H, Shim JH, Jung Kim H, Lee JR, Kim SC, Kwon YK, Ha KT, So I, Kim BJ. The traditional herbal medicine, Ge-Gen-Tang, inhibits pacemaker potentials by nitric oxide/cGMP dependent ATP-sensitive K(+) channels in cultured interstitial cells of Cajal from mouse small intestine. JOURNAL OF ETHNOPHARMACOLOGY 2015; 170:201-209. [PMID: 26003723 DOI: 10.1016/j.jep.2015.05.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 04/06/2015] [Accepted: 05/12/2015] [Indexed: 06/04/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Ge-Gen-Tang (GGT) is a traditional Chinese medicinal formula composed of Puerariae radix (Pueraria lobata Ohwi), Ephedrae Herba (Ephedra sinica Stapf), Cinnamomi Ramulus (Cinnamomum cassia Blume), Paeoniae Radix (Paeonia lactiflora Pallas), Glycyrrhizae Radix preparata (Glycyrrhiza uralensis Fischer), Zingiberis Rhizoma (Zingiber officinale Roscoe), and Zizyphi Fructus (Ziziphus jujuba Mill. var. inermis Rehder) and is widely used to ameoliorate the symptoms of gastrointestinal (GI) disorders related to diarrhea and intestinal mucosal immunity and for anti-cold, antipyretic and analgesic in Eastern Asia. AIM OF THE STUDY Interstitial cells of Cajal (ICCs) are pacemaker cells in the GI tract that generate rhythmic oscillations in membrane potentials known as slow waves. We investigated the effects of GGT on pacemaker potentials in cultured ICCs from the mouse small intestine, and sought to identify the receptors and the action mechanisms involved. MATERIALS AND METHODS Enzymatic digestions were used to dissociate ICCs from mouse small intestine tissues. All experiments on ICCs were performed on within 12h after culture. A whole-cell patch-clamp configuration was used to record potentials (current clamp) from cultured ICCs. Intracellular Ca(2+) ([Ca(2+)]i) increase was studied in cultured ICCs using fura-2AM. All of the experiments were performed at 30-32°C. RESULTS Under the current clamping mode, GGT decreased the amplitude and frequency of pacemaker potentials; however, these effects were blocked by intracellular GDPβS, a G-protein inhibitor, and glibenclamide, a specific ATP-sensitive K(+) channels blocker. Prazosin (α1-adrenoceptor antagonist) and butoxamine (β2-adrenoceptor antagonist) did not block the GGT-induced effects, whereas atenolol (β1-adrenoceptor antagonist) blocked the GGT-induced effects. Also, yohimbine (α2-adrenoceptor antagonist) partially blocked the GGT-induced effects. Pretreatment with SQ-22536, an adenylate cyclase inhibitor, did not block the GGT-induced effects, whereas pretreatment with ODQ, a guanylate cyclase inhibitor, or L-NAME, an inhibitor of nitric oxide (NO) synthase, did. Additionally, [Ca(2+)]i analysis showed that GGT decreased [Ca(2+)]i. CONCLUSION These results suggest that GGT inhibits pacemaker potentials in ICCs in a G protein-, cGMP- and NO-dependent manner through stimulation of α2 and β1-adrenoceptors.
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MESH Headings
- Animals
- Cells, Cultured
- Cyclic GMP/metabolism
- Drugs, Chinese Herbal/pharmacology
- Female
- Interstitial Cells of Cajal/drug effects
- Interstitial Cells of Cajal/metabolism
- Intestine, Small/cytology
- Intestine, Small/drug effects
- Intestine, Small/metabolism
- KATP Channels/metabolism
- Male
- Membrane Potentials/drug effects
- Mice
- Mice, Inbred BALB C
- Nitric Oxide/metabolism
- Patch-Clamp Techniques
- Receptors, Adrenergic, alpha-2/drug effects
- Receptors, Adrenergic, alpha-2/metabolism
- Receptors, Adrenergic, beta-1/drug effects
- Receptors, Adrenergic, beta-1/metabolism
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Affiliation(s)
- Soojin Lee
- Division of Longevity and Biofunctional Medicine, School of Korean Medicine, Pusan National University, Yangsan 626-870, Republic of Korea
| | - Huijin Gim
- Division of Longevity and Biofunctional Medicine, School of Korean Medicine, Pusan National University, Yangsan 626-870, Republic of Korea
| | - Ji Hwan Shim
- Division of Longevity and Biofunctional Medicine, School of Korean Medicine, Pusan National University, Yangsan 626-870, Republic of Korea
| | - Hyun Jung Kim
- Division of Longevity and Biofunctional Medicine, School of Korean Medicine, Pusan National University, Yangsan 626-870, Republic of Korea
| | - Jong Rok Lee
- Department of Pharmaceutical Engineering, Daegu Haany University, Gyeongsan 712-715, Republic of Korea
| | - Sang Chan Kim
- College of Oriental Medicine, Daegu Haany University, Gyeongsan 712-715, Republic of Korea
| | - Young Kyu Kwon
- Division of Longevity and Biofunctional Medicine, School of Korean Medicine, Pusan National University, Yangsan 626-870, Republic of Korea
| | - Ki-Tae Ha
- Division of Applied Medicine, School of Korean Medicine, Pusan National University, Yangsan 626-870, Republic of Korea
| | - Insuk So
- Department of Physiology, College of Medicine, Seoul National University, Seoul 110-799, Republic of Korea
| | - Byung Joo Kim
- Division of Longevity and Biofunctional Medicine, School of Korean Medicine, Pusan National University, Yangsan 626-870, Republic of Korea.
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Hu LD, Yu BP, Yang B. Deoxycholic acid inhibits smooth muscle contraction via protein kinase C-dependent modulation of L-type Ca2+ channels in rat proximal colon. Mol Med Rep 2012; 6:833-7. [PMID: 22798019 DOI: 10.3892/mmr.2012.984] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 06/15/2012] [Indexed: 11/06/2022] Open
Abstract
The aim of this study was to investigate the effects of deoxycholic acid (DCA) on the contractions of rat proximal colonic smooth muscle (PCSM) in vitro. The contractile response of rat PCSM strips was tested using a polyphysio-graph. The whole cell patch-clamp technique was also used in rat colonic smooth muscle cells (SMCs) isolated by an enzymatic procedure to record the L-type calcium current (I(Ca-L)) prior to and following the application of various concentrations of DCA. The application of DCA (10(-6)-10(-4) M) decreased the amplitude of spontaneous contractions of the PCSM strips in a dose-dependent manner. The administration of DCA (10(-5) M) caused the relaxation of isolated smooth muscle strips pre-contracted by acetylcholine (Ach) or KCl (by 12.2±1.5 and 16.3±6.9%, respectively). The concentration-response curve of CaCl2 was shifted to the right. Pre-treatment of the strips with the protein kinase C (PKC) inhibitor chelerythrine (1 µM) significantly attenuated the effects of DCA on the strips pre-contracted by Ach. DCA reduced the peak I(Ca-L) by 6.02±0.87% at 10(-6) M, 15.02±1.73% at 10(-5) M and 47.14±3.79% at 10(-4) M. DCA shifted the current-voltage (I-V) curve of ICa-L upward, but the contour of the I-V curve was unchanged, and the peak current-induced voltage remained at 0 mV. Pre-treatment with chelerythrine (1 µM) blocked the actions of DCA on the I(Ca-L). Taken together, the actions of DCA on I(Ca-L) in rat colonic SMCs contributed to a negative inotropic effect. These actions appear to be mediated through protein kinase C. Furthermore, this study suggests another possible mechanism for the DCA-related modulation of gastrointestinal motility.
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Affiliation(s)
- Liu-Dan Hu
- Department of Gastroenterology, Renmin Hospital of Wuhan University, Wuhan, Hubei, PR China
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Han S, Kim JS, Jung BK, Han SE, Nam JH, Kwon YK, Nah SY, Kim BJ. Effects of ginsenoside on pacemaker potentials of cultured interstitial cells of Cajal clusters from the small intestine of mice. Mol Cells 2012; 33:243-9. [PMID: 22350744 PMCID: PMC3887704 DOI: 10.1007/s10059-012-2204-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Revised: 11/16/2011] [Accepted: 12/12/2011] [Indexed: 12/15/2022] Open
Abstract
Ginsenoside, one of the active ingredients of Panax ginseng, has a variety of physiological and pharmacological actions in various organs. However, little is known about the effects of ginsenosides on gastrointestinal (GI) motility. We studied the modulation of pacemaker potentials by ginsenoside in the interstitial cells of Cajal (ICCs) using the whole-cell patch clamp technique in the current clamp mode. Among ginsenosides, we investigated the effects of ginsenoside Rb1, Rg3 and Rf. While externally applied Rb1 and Rg3 had no effects on pacemaker potentials, Rf caused membrane depolarization. The application of flufenamic acid or niflumic acid abolished the generation of pacemaker potentials and inhibited the Rf-induced membrane depolarization. Membrane depolarization induced by Rf was not inhibited by intracellular application of guanosine 5'-[β-thio]diphosphate trilithium salt. Pretreatment with a Ca(2+)-free solution, thapsigargin, a Ca(2+)-ATPase inhibitor of the endoplasmic reticulum, U-73122, a phospholipase C inhibitor, or 2-APB, an IP3 receptor inhibitor, abolished the generation of pacemaker potentials and suppressed Rfinduced actions. However, treatment with chelerythrine and calphostin C, protein kinase C inhibitors, did not block Rf-induced effects on pacemaker potentials. These results suggest that ginsenoside Rf modulates the pacemaker activities of ICCs and thereby regulates intestinal motility.
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Affiliation(s)
- Seungheon Han
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan 626-870,
Korea
| | - Jung Soo Kim
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan 626-870,
Korea
| | - Bo Kyoung Jung
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan 626-870,
Korea
| | - Song Ee Han
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan 626-870,
Korea
| | - Joo Hyun Nam
- Department of Physiology, Dongguk University College of Medicine, Kyungju 780-714,
Korea
| | - Young Kyu Kwon
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan 626-870,
Korea
| | - Seung-Yeol Nah
- Department of Physiology, Konkuk University College of Veterinary Medicine, Seoul 143-701,
Korea
| | - Byung Joo Kim
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan 626-870,
Korea
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Lee HK, Lee KH, Cho ES. Bile Acid Inhibition of N-type Calcium Channel Currents from Sympathetic Ganglion Neurons. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2012; 16:25-30. [PMID: 22416216 PMCID: PMC3298822 DOI: 10.4196/kjpp.2012.16.1.25] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 12/30/2011] [Accepted: 01/08/2012] [Indexed: 12/17/2022]
Abstract
Under some pathological conditions as bile flow obstruction or liver diseases with the enterohepatic circulation being disrupted, regurgitation of bile acids into the systemic circulation occurs and the plasma level of bile acids increases. Bile acids in circulation may affect the nervous system. We examined this possibility by studying the effects of bile acids on gating of neuronal (N)-type Ca2+ channel that is essential for neurotransmitter release at synapses of the peripheral and central nervous system. N-type Ca2+ channel currents were recorded from bullfrog sympathetic neuron under a cell-attached mode using 100 mM Ba2+ as a charge carrier. Cholic acid (CA, 10-6 M) that is relatively hydrophilic thus less cytotoxic was included in the pipette solution. CA suppressed the open probability of N-type Ca2+ channel, which appeared to be due to an increase in null (no activity) sweeps. For example, the proportion of null sweep in the presence of CA was ~40% at +40 mV as compared with ~8% in the control recorded without CA. Other single channel properties including slope conductance, single channel current amplitude, open and shut times were not significantly affected by CA being present. The results suggest that CA could modulate N-type Ca2+ channel gating at a concentration as low as 10-6 M. Bile acids have been shown to activate nonselective cation conductance and depolarize the cell membrane. Under pathological conditions with increased circulating bile acids, CA suppression of N-type Ca2+ channel function may be beneficial against overexcitation of the synapses.
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Affiliation(s)
- Hye Kyung Lee
- Department of Pharmacology, University of Ulsan College of Medicine, Seoul 138-736, Korea
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9
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Yoon PJ, Parajuli SP, Zuo DC, Shahi PK, Oh HJ, Shin HR, Lee MJ, Yeum CH, Choi S, Jun JY. Interplay of hydrogen sulfide and nitric oxide on the pacemaker activity of interstitial cells of cajal from mouse small intestine. Chonnam Med J 2011; 47:72-9. [PMID: 22111064 PMCID: PMC3214878 DOI: 10.4068/cmj.2011.47.2.72] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 08/11/2011] [Indexed: 01/17/2023] Open
Abstract
We studied whether nitric oxide (NO) and hydrogen sulfide (H(2)S) have an interaction on the pacemaker activities of interstitial cells of Cajal (ICC) from the mouse small intestine. The actions of NO and H(2)S on pacemaker activities were investigated by using the whole-cell patch-clamp technique and intracellular Ca(2+) analysis at 30℃ in cultured mouse ICC. Exogenously applied (±)-S-nitroso-N-acetylpenicillamine (SNAP), an NO donor, or sodium hydrogen sulfide (NaHS), a donor of H(2)S, showed no influence on pacemaker activity (potentials and currents) in ICC at low concentrations (10 µM SNAP and 100 µM NaHS), but SNAP or NaHS completely inhibited pacemaker amplitude and pacemaker frequency with increases in the resting currents in the outward direction at high concentrations (SNAP 100 µM and NaHS 1 mM). Co-treatment with 10 µM SNAP plus 100 µM NaHS also inhibited pacemaker amplitude and pacemaker frequency with increases in the resting currents in the outward direction. ODQ, a guanylate cyclase inhibitor, or glibenclamide, an ATP-sensitive K(+) channel inhibitor, blocked the SNAP+NaHS-induced inhibition of pacemaker currents in ICC. Also, we found that SNAP+NaHS inhibited the spontaneous intracellular Ca(2+) ([Ca(2+)](i)) oscillations in cultured ICC. In conclusion, this study describes the enhanced inhibitory effects of NO plus H(2)S on ICC in the mouse small intestine. NO+H(2)S inhibited the pacemaker activity of ICC by modulating intracellular Ca(2+). These results may be evidence of a physiological interaction of NO and H(2)S in ICC for modulating gastrointestinal motility.
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Affiliation(s)
- Pyung Jin Yoon
- Department of Physiology, College of Medicine, Chosun University, Gwangju, Korea
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10
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Choi S, Yeum CH, Kim YD, Park CG, Kim MY, Park JS, Jeong HS, Kim BJ, So I, Kim KW. Receptor tyrosine and MAP kinase are involved in effects of H(2)O(2) on interstitial cells of Cajal in murine intestine. J Cell Mol Med 2011; 14:257-66. [PMID: 20414970 PMCID: PMC3837618 DOI: 10.1111/j.1582-4934.2008.00403.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Hydrogen peroxide (H(2)O(2)) is involved in intestinal motility through changes of smooth muscle activity. However, there is no report as to the modulatory effects of H(2)O(2) on interstitial cells of Cajal (ICC). We investigated the H(2)O(2) effects and signal transductions to determine whether the intestinal motility can be modulated through ICC. We performed whole-cell patch clamp in cultured ICC from murine intestine and molecular analyses. H(2)O(2) hyperpolarized the membrane and inhibited pacemaker currents. These effects were inhibited by glibenclamide, an inhibitor of ATP-sensitive K+ (K(ATP)) channels. The free-radical scavenger catalase inhibited the H(2)O(2)-induced effects. MAFP and AACOCF3 (a cytosolic phospholipase A2 inhibitors) or SC-560 and NS-398 (a selective COX-1 and 2 inhibitor) or AH6809 (an EP2 receptor antagonist) inhibited the H(2)O(2)-induced effects. PD98059 (a mitogen activated/ERK-activating protein kinase inhibitor) inhibited the H(2)O(2)-induced effects, though SB-203580 (a p38 MAPK inhibitor) or a JNK inhibitor did not affect. H(2)O(2)-induced effects could not be inhibited by LY-294002 (an inhibitor of PI3-kinases), calphostin C (a protein kinase C inhibitor) or SQ-22536 (an adenylate cyclase inhibitor). Adenoviral infection analysis revealed H2O2 stimulated tyrosine kinase activity and AG 1478 (an antagonist of epidermal growth factor receptor tyrosine kinase) inhibited the H(2)O(2)-induced effects. These results suggest H(2)O(2) can modulate ICC pacemaker activity and this occur by the activation of K(ATP) channels through PGE(2) production via receptor tyrosine kinase-dependent MAP kinase activation.
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Affiliation(s)
- Seok Choi
- Department of Physiology, College of Medicine, Chosun University, Gwangju, Korea
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11
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Baldassano S, Rotondo A, Serio R, Livrea MA, Tesoriere L, Mulè F. Inhibitory effects of indicaxanthin on mouse ileal contractility: analysis of the mechanism of action. Eur J Pharmacol 2011; 658:200-5. [PMID: 21371457 DOI: 10.1016/j.ejphar.2011.02.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 01/21/2011] [Accepted: 02/15/2011] [Indexed: 11/28/2022]
Abstract
Recently, we have showed that indicaxanthin, the yellow betalain pigment abundant in the fruit of Opuntia ficus indica, has remarkable spasmolytic effects on the intestinal contractility in vitro. Thus, the purpose of the present study was to investigate the mechanism of action underlying the observed response. We used organ bath technique to record the mechanical activity of the mouse ileum longitudinal muscle and ELISA to measure the levels of cAMP. Indicaxanthin induced inhibitory effects on spontaneous mechanical activity, which were unaffected by indomethacin, a non-selective inhibitor of cycloxygenase; 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, a selective inhibitor of nitric oxide-dependent guanylyl cyclase; 2'5'dideoxyadenosine, an adenylyl cyclase inhibitor; and zaprinast, a selective inhibitor of the cGMP phosphodiesterase isoenzyme. Indicaxanthin effects were reduced significantly in the presence of 3-isobutyl-1-methylxanthine (IBMX), a non selective inhibitor of phosphodiesterases (PDEs). Indicaxanthin and IBMX significantly reduced the carbachol-evoked contractions and the joint application of both drugs did not produce any additive effect. Indicaxanthin and IBMX increased the inhibitory effects of forskolin, an adenylyl cyclase activator, and the joint application of both drugs did not produce any additive effect. Indicaxanthin, contrarily to IBMX, did not affect the inhibitory action of sodium nitroprusside, a soluble guanylyl cyclase activator. Indicaxanthin increased both basal and forskolin-induced cAMP content of mouse ileal muscle. The present data show that indicaxanthin reduces the contractility of ileal longitudinal muscle by inhibition of PDEs and increase of cAMP concentration and raise the possibility of using indicaxanthin in the treatment of motility disorders, such as abdominal cramps.
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Affiliation(s)
- Sara Baldassano
- Dipartimento di Biologia cellulare e dello Sviluppo, Università di Palermo, 90128 Palermo, Italy
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12
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Kim BJ, Chae H, Kwon YK, Choi S, Jun JY, Jeon JH, So I, Kim SJ. Effects of imatinib mesylate in interstitial cells of Cajal from murine small intestine. Biol Pharm Bull 2011; 33:993-7. [PMID: 20522965 DOI: 10.1248/bpb.33.993] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The interstitial cells of Cajal (ICCs) are pacemakers in the gastrointestinal tract. The possibility of whether imatinib mesylate, a Kit receptor tyrosine kinase inhibitor, modulates pacemaker activities in the ICC was examined using the whole cell patch clamp technique. Imatinib decreased the amplitude of pacemaker potentials in a dose-dependent manner in current-clamp mode. Because the effects of imatinib on pacemaker potentials were the same as those of pinacidil, we examined the effect of glibenclamide on ICC exposed to imatinib. The effects of imatinib on pacemaker potentials were blocked by glibenclamide. To see whether the production of prostaglandins (PGs) is involved in the inhibitory effect of imatinib on pacemaker potentials, we tested the effects of naproxen (a non-selective cyclooxygenase inhibitor) and AH6809 (a prostaglandin EP1 and EP2 receptor antagonist). Naproxen and AH6809 blocked the inhibitory effects of imatinib on ICC. Butaprost (an EP2 receptor agonist) showed the actions on pacemaker potentials in the same manner as imatinib. However, SC 19220 (an EP1 receptor antagonist) has no effects. To investigate the involvement of cAMP and protein kinase A (PKA) in the effects of imatinib on ICC, SQ 22536 (an inhibitor of adenylate cyclase) and mPKAI (an inhibitor of myristoylated PKA) were used. Both SQ-22536 and mPKAI blocked the imatinib-mediated inhibition of pacemaker potentials. However, the protein kinase C (PKC) inhibitors did not block the imatinib-mediated inhibition of pacemaker potentials. These results indicate that imatinib inhibits the pacemaker potentials of ICC by activating ATP-sensitive K(+) channels and PKA-dependent, PKC-independent manner.
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Affiliation(s)
- Byung Joo Kim
- Division of Longevity and Biofunctional Medicine, Pusan National University School of Korean Medicine, Yangsan 626-870, Republic of Korea
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Lavoie B, Balemba OB, Godfrey C, Watson CA, Vassileva G, Corvera CU, Nelson MT, Mawe GM. Hydrophobic bile salts inhibit gallbladder smooth muscle function via stimulation of GPBAR1 receptors and activation of KATP channels. J Physiol 2010; 588:3295-305. [PMID: 20624794 DOI: 10.1113/jphysiol.2010.192146] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Hydrophobic bile salts are thought to contribute to the disruption of gallbladder smooth muscle (GBSM) function that occurs in gallstone disease, but their mechanism of action is unknown. The current study was undertaken to determine how hydrophobic bile salts interact with GBSM, and how they reduce GBSM activity. The effect of hydrophobic bile salts on the activity of GBSM was measured by intracellular recording and calcium imaging using wholemount preparations from guinea pig and mouse gallbladder. RT-PCR and immunohistochemistry were used to evaluate expression of the G protein-coupled bile acid receptor, GPBAR1. Application of tauro-chenodeoxycholate (CDC, 50-100 microm) to in situ GBSM rapidly reduced spontaneous Ca(2+) flashes and action potentials, and caused a membrane hyperpolarization. Immunoreactivity and transcript for GPBAR1 were detected in gallbladder muscularis. The GPBAR1 agonist, tauro-lithocholic acid (LCA, 10 microm) mimicked the effect of CDC on GBSM. The actions of LCA were blocked by the protein kinase A (PKA) inhibitor, KT5720 (0.5-1.0 microm) and the K(ATP) channel blocker, glibenclamide (10 microm). Furthermore, LCA failed to disrupt GBSM activity in Gpbar1(/) mice. The findings of this study indicate that hydrophobic bile salts activate GPBAR1 on GBSM, and this leads to activation of the cyclic AMP-PKA pathway, and ultimately the opening of K(ATP) channels, thus hyperpolarizing the membrane and decreasing GBSM activity. This inhibitory effect of hydrophobic bile salt activation of GPBAR1 could be a contributing factor in the manifestation of gallstone disease.
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Affiliation(s)
- Brigitte Lavoie
- Department of Anatomy and Neurobiology, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington VT 05405, USA
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14
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Takaki M, Suzuki H, Nakayama S. Recent advances in studies of spontaneous activity in smooth muscle: ubiquitous pacemaker cells. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2010; 102:129-35. [PMID: 20553741 DOI: 10.1016/j.pbiomolbio.2010.05.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Accepted: 05/19/2010] [Indexed: 02/08/2023]
Abstract
The general and specific properties of pacemaker cells, including Kit-negative cells, that are distributed in gastrointestinal, urethral and uterine smooth muscle tissues, are discussed herein. In intestinal tissues, interstitial cells of Cajal (ICC) are heterogeneous in both their forms and roles. ICC distributed in the myenteric layer (ICC-MY) act as primary pacemaker cells for intestinal mechanical and electrical activity. ICC distributed in muscle bundles play a role as mediators of signals from autonomic nerves to smooth muscle cells. A group of ICC also appears to act as a stretch sensor. Intracellular Ca2+ dynamics play a crucial role in ICC-MY pacemaking; intracellular Ca2+ ([Ca2+](i)) oscillations periodically activate plasmalemmal Ca2+-activated ion channels, such as Ca2+-activated Cl(-) channels and/or non-selective cation channels, although the relative contributions of these channels are not defined. With respect to gut motility, both the ICC network and enteric nervous system, including excitatory and inhibitory enteric neurons, play an essential role in producing highly coordinated peristalsis.
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Affiliation(s)
- Miyako Takaki
- Department of Physiology II, Nara Medical University, 840 Shijo-cho, Kashihara 634-8521, Japan.
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15
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Ahn SW, Kim SH, Kim JH, Choi S, Yeum CH, Wie HW, Sun JM, So I, Jun JY. Phentolamine inhibits the pacemaker activity of mouse interstitial cells of Cajal by activating ATP-sensitive K+ channels. Arch Pharm Res 2010; 33:479-89. [DOI: 10.1007/s12272-010-0319-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 01/07/2010] [Accepted: 01/18/2010] [Indexed: 01/18/2023]
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16
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Nakayama S, Kajioka S, Goto K, Takaki M, Liu HN. Calcium-associated mechanisms in gut pacemaker activity. J Cell Mol Med 2008; 11:958-68. [PMID: 17979877 PMCID: PMC4401267 DOI: 10.1111/j.1582-4934.2007.00107.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
A considerable body of evidence has revealed that interstitial cells of Cajal (ICC), identified with c-Kit-immunoreactivity, act as gut pacemaker cells, with spontaneous Ca2+ activity in ICC as the probable primary mechanism. Namely, intracellular (cytosolic) Ca2+ oscillations in ICC periodically activate plasmalemmal Ca2+-dependent ion channels and thereby generate pacemaker potentials. This review will, thus, focus on Ca2+-associated mechanisms in ICC in the gastrointestinal (GI) tract, including auxiliary organs.
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Affiliation(s)
- Shinsuke Nakayama
- Department of Cell Physiology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
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Kim HS, Parajuli SP, Yeum CH, Park JS, Jeong HS, So I, Kim KW, Jun JY, Choi S. Effects of ginseng total saponins on pacemaker currents of interstitial cells of Cajal from the small intestine of mice. Biol Pharm Bull 2007; 30:2037-42. [PMID: 17978472 DOI: 10.1248/bpb.30.2037] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although ginsenosides have a variety of physiologic or pharmacologic functions in various regions, there are only a few reports on the effects of ginsenosides on gastrointestinal (GI) motility. We studied the modulation of pacemaker activities by ginseng total saponins in the interstitial cells of Cajal (ICC) using the whole cell patch-clamp technique. Externally applied ginseng total saponins (GTS) produced membrane depolarization in the current-clamp mode and increased tonic inward pacemaker currents in the voltage-clamp mode. The application of flufenamic acid or niflumic acid abolished the generation of pacemaker currents, but only treatment with flufenamic acid inhibited the GTS-induced tonic inward currents. The tonic inward currents induced by GTS were not inhibited by the intracellular application of guanosine 5'-[beta-thio]diphosphate trilithium salt. Pretreatment with a Ca(2+)-free solution, with U-73122, an active phospholipase C inhibitor, and with thapsigargin, a Ca(2')-ATPase inhibitor of the endoplasmic reticulum, abolished the generation of pacemaker currents and suppressed the GTS-induced action. However, treatment with chelerythrine and calphostin C, protein kinase C inhibitors, did not block the GTS-induced effects on the pacemaker currents. These results suggest that ginsenosides modulate the pacemaker activities of the ICC, and the ICC can be targets for ginsenosides, and their interaction can affect intestinal motility.
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Affiliation(s)
- Hyun Soo Kim
- Division of Gastroenterology, Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea
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Inhibition of pacemaker currents by nitric oxide via activation of ATP-sensitive K+ channels in cultured interstitial cells of Cajal from the mouse small intestine. Naunyn Schmiedebergs Arch Pharmacol 2007; 376:175-84. [PMID: 17932655 DOI: 10.1007/s00210-007-0187-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Accepted: 08/24/2007] [Indexed: 12/17/2022]
Abstract
We investigated the role of nitric oxide (NO) in pacemaker activity and signal mechanisms in cultured interstitial cells of Cajal (ICC) of the mouse small intestine using whole cell patch-clamp techniques at 30 degrees C. ICC generated pacemaker potential in the current clamp mode and pacemaker currents at a holding potential of -70 mV. (+/-)-S-nitroso-N-acetylpenicillamine (SNAP; a NO donor) produced membrane hyperpolarization and inhibited the amplitude and frequency of the pacemaker currents, and increased resting currents in the outward direction. These effects were blocked by the use of glibenclamide (an ATP-sensitive K+ channel blocker), but not by the use of 5-hydroxydecanoic acid (a mitochondrial ATP-sensitive K+ channel blocker). Pretreatment with ODQ (a guanylate cyclase inhibitor) almost blocked the NO-induced effects. The use of cell-permeable 8-bromo-cyclic GMP also mimicked the action of SNAP. However, the use of KT-5823 (a protein kinase G inhibitor) did not block the NO-induced effects. Spontaneous [Ca2+]i oscillations in ICC were inhibited by the treatment of SNAP, as seen in recordings of intracellular Ca2+ ([Ca2+]i). These results suggest that NO inhibits pacemaker activity by the activation of ATP-sensitive K+ channels via a cyclic GMP dependent mechanism in ICC, and the activation of ATP-sensitive K+ channels mediates the inhibition of spontaneous [Ca2+]i oscillations.
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Choi S, Yeum CH, Chang IY, You HJ, Park JS, Jeong HS, So I, Kim KW, Jun JY. Activating of ATP-dependent K+ channels comprised of K(ir) 6.2 and SUR 2B by PGE2 through EP2 receptor in cultured interstitial cells of Cajal from murine small intestine. Cell Physiol Biochem 2007; 18:187-98. [PMID: 17167224 DOI: 10.1159/000097516] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/14/2006] [Indexed: 11/19/2022] Open
Abstract
The interstitial cells of Cajal (ICC) are pacemaker cells in gastrointestinal tract and generate an electrical rhythm in gastrointestinal muscles. We investigated the possibility that PGE(2) might affect the electrical properties of cultured ICC by activating ATP-dependent K(+) channels and, the EP receptor subtypes and the subunits of ATP-dependent K(+) channels involved in these activities were identified. In addition, the regulation of intracellular Ca(2+) ([Ca(2+)](i)) mobilization may be involved the action of PGE(2) on ICC. Treatments of ICC with PGE(2) inhibited electrical pacemaker activities in the same manner as pinacidil, an ATP-dependent K(+) channel opener and PGE(2) had only a dose-dependent effect. Using RT-PCR technique, we found that ATP-dependent K(+) channels exist in ICC and that these are composed of K(ir) 6.2 and SUR 2B subunits. To characterize the specific membrane EP receptor subtypes in ICC, EP receptor agonists and RT-PCR were used: Butaprost (an EP(2) receptor agonist) showed the actions on pacemaker currents in the same manner as PGE(2). However sulprostone (a mixed EP(1) and EP(3) agonist) had no effects. In addition, RT-PCR results indicated the presence of the EP(2) receptor in ICC. To investigate cAMP involvement in the effects of PGE(2) on ICCs, SQ-22536 (an inhibitor of adenylate cyclase) and cAMP assays were used. SQ-22536 did not affect the effect of PGE(2) on pacemaker currents, and PGE(2) did not stimulate cAMP production. Also, we found PGE(2) inhibited the spontaneous [Ca(2+)](i) oscillations in cultured ICC. These observations indicate that PGE(2) alters pacemaker currents by activating the ATP-dependent K(+) channels comprised of K(ir) 6.2-SUR 2B in ICC and this action of PGE(2) are through EP(2) receptor subtype and also the activation of ATP-dependent K(+) channels involves intracellular Ca(2+) mobilization.
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MESH Headings
- ATP-Binding Cassette Transporters/agonists
- ATP-Binding Cassette Transporters/analysis
- ATP-Binding Cassette Transporters/genetics
- Adenine/analogs & derivatives
- Adenine/pharmacology
- Adenosine Triphosphate/metabolism
- Adenylyl Cyclase Inhibitors
- Alprostadil/analogs & derivatives
- Alprostadil/pharmacology
- Animals
- Calcium/metabolism
- Cells, Cultured
- Dinoprostone/pharmacology
- Dose-Response Relationship, Drug
- Electrophysiology
- Female
- Intestine, Small/chemistry
- Intestine, Small/cytology
- Intestine, Small/drug effects
- Male
- Membrane Potentials
- Mice
- Mice, Inbred BALB C
- Potassium Channels/agonists
- Potassium Channels/analysis
- Potassium Channels/genetics
- Potassium Channels, Inwardly Rectifying/agonists
- Potassium Channels, Inwardly Rectifying/analysis
- Potassium Channels, Inwardly Rectifying/genetics
- Receptors, Drug/agonists
- Receptors, Drug/analysis
- Receptors, Drug/genetics
- Receptors, Prostaglandin E/metabolism
- Receptors, Prostaglandin E, EP2 Subtype
- Sulfonylurea Receptors
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Affiliation(s)
- Seok Choi
- Department of Physiology, College of Medicine, Chosun University, 375 Seosuk-dong, Gwangju, South Korea
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Colecchia A, Mazzella G, Sandri L, Azzaroli F, Magliuolo M, Simoni P, Bacchi-Reggiani ML, Roda E, Festi D. Ursodeoxycholic acid improves gastrointestinal motility defects in gallstone patients. World J Gastroenterol 2006; 12:5336-43. [PMID: 16981264 PMCID: PMC4088201 DOI: 10.3748/wjg.v12.i33.5336] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To simultaneously evaluate the presence of defects in gallbladder and gastric emptying, as well as in intestinal transit in gallstone patients (GS) and the effect of chronic ursodeoxycholic acid (UDCA) administration on these parameters and on serum bile acids and clinical outcome in GS and controls (CTR).
METHODS: After a standard liquid test meal, gallbla-dder and gastric emptying (by ultrasound), oroileal transit time (OITT) (by an immunoenzymatic technique) and serum bile acids (by HPLC) were evaluated before and after 3 mo of UDCA (12 mg/kg bw/d) or placebo administration in 10 symptomatic GS and 10 matched healthy CTR.
RESULTS: OITT was longer in GS than in CTR (P < 0.0001); UDCA significantly reduced OITT in GS (P < 0.0001), but not in CTR. GS had longer gastric half-emptying time (t1/2) than CTR (P < 0.0044) at baseline; after UDCA, t1/2 significantly decreased (P < 0.006) in GS but not in CTR. Placebo administration had no effect on gastric emptying and intestinal transit in both GS and CTR.
CONCLUSION: The gallstone patient has simultaneous multiple impairments of gallbladder and gastric emptying, as well as of intestinal transit. UDCA administration restores these defects in GS, without any effect in CTR. These results confirm the pathogenetic role of gastrointestinal motility in gallstone disease and suggest an additional mechanism of action for UDCA in reducing bile cholesterol supersaturation.
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Affiliation(s)
- A Colecchia
- Dipartmento di Medicina Interna e Gastroenterologia Policlinico S.Orsola-Malpighi Via Massarenti 9, Bologna 40138, Italy
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de Waart DR, Paulusma CC, Kunne C, Oude Elferink RPJ. Multidrug resistance associated protein 2 mediates transport of prostaglandin E2. Liver Int 2006; 26:362-8. [PMID: 16584400 DOI: 10.1111/j.1478-3231.2005.01234.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND/AIM Inactivation of prostaglandin E(2) (PGE(2)) in the liver is a rapid process and occurs mainly through beta-oxidation in the peroxisome of the hepatocyte. Biliary excretion of PGE(2) is also a means of elimination from the liver. We investigated the role of multidrug resistance-associated protein 2 (MRP2) in the transport of PGE(2). METHODS Biliary PGE(2) elimination was measured in liver perfusions in Wistar and MRP2-deficient TR(-) rats. Furthermore, transport experiments were performed in membrane vesicles from human MRP2-infected Spodoptera frugiperda 21 (Sf21) insect cells. RESULTS The liver perfusions showed a 3.5 times higher percentage of undegraded [(3)H]PGE(2) in bile of Wistar rats in comparison with MRP2 deficient (TR(-)) rats (3.6% vs. 1.1%, respectively; P<0.05). MRP2-mediated transport of the model substrate [(3)H]DNP-SG was inhibited by PGE(2). Half maximal inhibition was achieved at a concentration of approximately 15 microM PGE(2). In addition, [(3)H]PGE(2) uptake in these vesicles was detected, and determined to be ATP dependent. CONCLUSION MRP2 mediates the transport of PGE(2) and its breakdown products. The biliary excretion of PGE(2) via MRP2 may contribute to rapid elimination of the prostaglandin but might also serve to relay prostaglandin signalling to the biliary tree.
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Affiliation(s)
- Dirk R de Waart
- Department of Experimental Hepatology, Academic Medical Center, Amsterdam, the Netherlands.
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Choi S, Park CG, Kim MY, Lim GH, Kim JH, Yeum CH, Yoon PJ, So I, Kim KW, Jun JY. Action of imipramine on activated ATP-sensitive K(+) channels in interstitial cells of Cajal from murine small intestine. Life Sci 2005; 78:2322-8. [PMID: 16266721 DOI: 10.1016/j.lfs.2005.09.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2005] [Accepted: 09/20/2005] [Indexed: 11/26/2022]
Abstract
Tricyclic antidepressants have been widely used for the treatment of depression and as a therapeutic agent for the altered gastrointestinal (GI) motility of irritable bowel syndrome (IBS). The aim of this study was to clarify whether antidepressants directly modulate pacemaker currents in cultured interstitial cells of Cajal (ICC). We used the whole-cell patch-clamp techniques at 30 degrees C in cultured ICC from the mouse small intestine. Treatment of pinacidil, an ATP-sensitive K(+) channel opener, in the ICC using the current clamping mode, produced hyperpolarization of the membrane potential and decreased the amplitude of the pacemaker potentials. With the voltage clamp mode, we observed a decrease in the frequency and amplitude of pacemaker currents and increases in the resting outward currents. These effects of pinacidil on pacemaker potentials and currents were completely suppressed by glibenclamide, an ATP-sensitive K(+) channel blocker. Also, with the current clamp mode, imipramine blocked the affect of pinacidil on the pacemaker potentials. Observations of the voltage clamp mode with imipramine, desipramine and amitryptyline suppressed the action of pinacidil in the ICC. Next, we examined whether protein kinase C (PKC) and the G protein are involved in the action of imipramine on pinacidil induced pacemaker current inhibition. We used chelerythrine, a potent PKC inhibitor and GDPbetaS, a nonhydrolyzable guanosine 5-diphosphate (GDP) analogue that permanently inactivates GTP-binding proteins. We found that pretreatment with chelerythrine and intracellular application of GDPbetaS had no influence on the blocking action of imipramine on inhibited pacemaker currents by pinacidil. We conclude that imipramine inhibited the activated ATP-sensitive K(+) channels in ICC. This action does not appear to be mediated through the G protein and protein kinase C. Furthermore, this study may suggest another possible mechanism for tricyclic antidepressants related modulation of GI motility.
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Affiliation(s)
- Seok Choi
- Department of Physiology, College of Medicine, Chosun University, 375 Seosuk-dong, Gwangju, Korea
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