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Zhou M, Li TS, Abe H, Akashi H, Suzuki R, Bando Y. Expression levels of K ATP channel subunits and morphological changes in the mouse liver after exposure to radiation. World J Exp Med 2024; 14:90374. [PMID: 38948415 PMCID: PMC11212743 DOI: 10.5493/wjem.v14.i2.90374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 01/28/2024] [Accepted: 03/27/2024] [Indexed: 06/19/2024] Open
Abstract
BACKGROUND ATP sensitive K+ (KATP) channels are ubiquitously distributed in various of cells and tissues, including the liver. They play a role in the pathogenesis of myocardial and liver ischemia. AIM To evaluate the radiation-induced changes in the expression of KATP channel subunits in the mouse liver to understand the potential role of KATP channels in radiation injury. METHODS Adult C57BL/6 mice were randomly exposed to γ-rays at 0 Gy (control, n = 2), 0.2 Gy (n = 6), 1 Gy (n = 6), or 5 Gy (n = 6). The livers were removed 3 and 24 h after radiation exposure. Hematoxylin and eosin staining was used for morphological observation; immunohistochemical staining was applied to determine the expression of KATP channel subunits in the liver tissue. RESULTS Compared with the control group, the livers exposed to 0.2 Gy γ-ray showed an initial increase in the expression of Kir6.1 at 3 h, followed by recovery at 24 h after exposure. Exposure to a high dose of 5.0 Gy resulted in decreased expression of Kir6.1 and increased expression of SUR2B at 24 h. However, the expression of Kir6.2, SUR1, or SUR2A had no remarkable changes at 3 and 24 h after exposure to any of these doses. CONCLUSION The expression levels of Kir6.1 and SUR2B in mouse liver changed differently in response to different radiation doses, suggesting a potential role for them in radiation-induced liver injury.
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Affiliation(s)
- Ming Zhou
- Department of Anatomy, Akita University Graduate School of Medicine, Akita 010-8543, Japan
| | - Tao-Sheng Li
- Department of Stem Cell Biology, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki 852-8523, Japan
| | - Hiroshi Abe
- Sendai Old Age Refresh Station, A Long-term Care Health Facility, Sendai 981-1105, Japan
| | - Hideo Akashi
- Department of Anatomy, Akita University Graduate School of Medicine, Akita 010-8543, Japan
| | - Ryoji Suzuki
- Department of Anatomy, Akita University Graduate School of Medicine, Akita 010-8543, Japan
| | - Yoshio Bando
- Department of Anatomy, Akita University Graduate School of Medicine, Akita 010-8543, Japan
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Zhou M, Yoshikawa K, Akashi H, Miura M, Suzuki R, Li TS, Abe H, Bando Y. Localization of ATP-sensitive K + channel subunits in rat liver. World J Exp Med 2019; 9:14-31. [PMID: 31938690 PMCID: PMC6955576 DOI: 10.5493/wjem.v9.i2.14] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 09/05/2019] [Accepted: 11/21/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND ATP-sensitive K+ (KATP) channels were originally found in cardiac myocytes by Noma in 1983. KATP channels were formed by potassium ion-passing pore-forming subunits (Kir6.1, Kir6.2) and regulatory subunits SUR1, SU2A and SUR2B. A number of cells and tissues have been revealed to contain these channels including hepatocytes, but detailed localization of these subunits in different types of liver cells was still uncertain.
AIM To investigate the expression of KATP channel subunits in rat liver and their localization in different cells of the liver.
METHODS Rabbit anti-rat SUR1 peptide antibody was raised and purified by antigen immunoaffinity column chromatography. Four of Sprague-Dawley rats were used for liver protein extraction for immunoblot analysis, seven of them were used for immunohistochemistry both for the ABC method and immunofluorescence staining. Four of Wistar rats were used for the isolation of hepatic stellate cells (HSCs) and Kupffer cells for both primary culture and immunocytochemistry.
RESULTS Immunoblot analysis showed that the five kinds of KATP channel subunits, i.e. Kir6.1, Kir6.2, SUR1, SUR2A, and SUR2B, were detected in liver. Immunohistochemical staining showed that Kir6.1 and Kir6.2 were weakly to moderately expressed in parenchymal cells and sinusoidal lining cells, while SUR1, SUR2A, and SUR2B were mainly localized to sinusoidal lining cells, such as HSCs, Kupffer cells, and sinusoidal endothelial cells. Immunoreactivity for SUR2A and SUR2B was expressed in the hepatocyte membrane. Double immunofluorescence staining further showed that the pore-forming subunits Kir6.1 and/or Kir6.2 colocalized with GFAP in rat liver sections and primary cultured HSCs. These KATP channel subunits also colocalized with CD68 in liver sections and primary cultured Kupffer cells. The SUR subunits colocalized with GFAP in liver sections and colocalized with CD68 both in liver sections and primary cultured Kupffer cells. In addition, five KATP channel subunits colocalized with SE-1 in sinusoidal endothelial cells.
CONCLUSION Observations from the present study indicated that KATP channel subunits expressed in rat liver and the diversity of KATP channel subunit composition might form different types of KATP channels. This is applicable to hepatocytes, HSCs, various types of Kupffer cells and sinusoidal endothelial cells.
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Affiliation(s)
- Ming Zhou
- Department of Anatomy, Akita University Graduate School of Medicine, Akita 010-8543, Japan
| | - Kiwamu Yoshikawa
- Department of Cell Biology and Morphology, Akita University Graduate School of Medicine, Akita 010-8543, Japan
| | - Hideo Akashi
- Department of Anatomy, Akita University Graduate School of Medicine, Akita 010-8543, Japan
| | - Mitsutaka Miura
- Department of Cell Biology and Morphology, Akita University Graduate School of Medicine, Akita 010-8543, Japan
| | - Ryoji Suzuki
- Department of Anatomy, Akita University Graduate School of Medicine, Akita 010-8543, Japan
| | - Tao-Sheng Li
- Department of Stem Cell Biology, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki 852-8523, Japan
| | - Hiroshi Abe
- TRUST, A Long-Term Care Health Facility, Sendai 980-0011, Japan
| | - Yoshio Bando
- Department of Anatomy, Akita University Graduate School of Medicine, Akita 010-8543, Japan
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Tykocki NR, Boerman EM, Jackson WF. Smooth Muscle Ion Channels and Regulation of Vascular Tone in Resistance Arteries and Arterioles. Compr Physiol 2017; 7:485-581. [PMID: 28333380 DOI: 10.1002/cphy.c160011] [Citation(s) in RCA: 222] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Vascular tone of resistance arteries and arterioles determines peripheral vascular resistance, contributing to the regulation of blood pressure and blood flow to, and within the body's tissues and organs. Ion channels in the plasma membrane and endoplasmic reticulum of vascular smooth muscle cells (SMCs) in these blood vessels importantly contribute to the regulation of intracellular Ca2+ concentration, the primary determinant of SMC contractile activity and vascular tone. Ion channels provide the main source of activator Ca2+ that determines vascular tone, and strongly contribute to setting and regulating membrane potential, which, in turn, regulates the open-state-probability of voltage gated Ca2+ channels (VGCCs), the primary source of Ca2+ in resistance artery and arteriolar SMCs. Ion channel function is also modulated by vasoconstrictors and vasodilators, contributing to all aspects of the regulation of vascular tone. This review will focus on the physiology of VGCCs, voltage-gated K+ (KV) channels, large-conductance Ca2+-activated K+ (BKCa) channels, strong-inward-rectifier K+ (KIR) channels, ATP-sensitive K+ (KATP) channels, ryanodine receptors (RyRs), inositol 1,4,5-trisphosphate receptors (IP3Rs), and a variety of transient receptor potential (TRP) channels that contribute to pressure-induced myogenic tone in resistance arteries and arterioles, the modulation of the function of these ion channels by vasoconstrictors and vasodilators, their role in the functional regulation of tissue blood flow and their dysfunction in diseases such as hypertension, obesity, and diabetes. © 2017 American Physiological Society. Compr Physiol 7:485-581, 2017.
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Affiliation(s)
- Nathan R Tykocki
- Department of Pharmacology, University of Vermont, Burlington, Vermont, USA
| | - Erika M Boerman
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri, USA
| | - William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan, USA
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Dick GM, Tune JD. Role of potassium channels in coronary vasodilation. Exp Biol Med (Maywood) 2010; 235:10-22. [DOI: 10.1258/ebm.2009.009201] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
K+ channels in coronary arterial smooth muscle cells (CASMC) determine the resting membrane potential ( Em) and serve as targets of endogenous and therapeutic vasodilators. Em in CASMC is in the voltage range for activation of L-type Ca2+ channels; therefore, when K+ channel activity changes, Ca2+ influx and arterial tone change. This is why both Ca2+ channel blockers and K+ channel openers have such profound effects on coronary blood flow; the former directly inhibits Ca2+ influx through L-type Ca2+ channels, while the latter indirectly inhibits Ca2+ influx by hyperpolarizing Em and reducing Ca2+ channel activity. K+ channels in CASMC play important roles in vasodilation to endothelial, ischemic and metabolic stimuli. The purpose of this article is to review the types of K+ channels expressed in CASMC, discuss the regulation of their activity by physiological mechanisms and examine impairments related to cardiovascular disease.
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Affiliation(s)
- Gregory M Dick
- Department of Exercise Physiology and Center for Cardiovascular & Respiratory Sciences, West Virginia University School of Medicine, Morgantown, WV 26506
| | - Johnathan D Tune
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Dick GM, Bratz IN, Borbouse L, Payne GA, Dincer UD, Knudson JD, Rogers PA, Tune JD. Voltage-dependent K+ channels regulate the duration of reactive hyperemia in the canine coronary circulation. Am J Physiol Heart Circ Physiol 2008; 294:H2371-81. [PMID: 18375717 DOI: 10.1152/ajpheart.01279.2007] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We previously demonstrated a role for voltage-dependent K(+) (K(V)) channels in coronary vasodilation elicited by myocardial metabolism and exogenous H(2)O(2), as responses were attenuated by the K(V) channel blocker 4-aminopyridine (4-AP). Here we tested the hypothesis that K(V) channels participate in coronary reactive hyperemia and examined the role of K(V) channels in responses to nitric oxide (NO) and adenosine, two putative mediators. Reactive hyperemia (30-s occlusion) was measured in open-chest dogs before and during 4-AP treatment [intracoronary (ic), plasma concentration 0.3 mM]. 4-AP reduced baseline flow 34 +/- 5% and inhibited hyperemic volume 32 +/- 5%. Administration of 8-phenyltheophylline (8-PT; 0.3 mM ic or 5 mg/kg iv) or N(G)-nitro-L-arginine methyl ester (L-NAME; 1 mg/min ic) inhibited early and late portions of hyperemic flow, supporting roles for adenosine and NO. 4-AP further inhibited hyperemia in the presence of 8-PT or L-NAME. Adenosine-induced blood flow responses were attenuated by 4-AP (52 +/- 6% block at 9 microg/min). Dilation of arterioles to adenosine was attenuated by 0.3 mM 4-AP and 1 microM correolide, a selective K(V)1 antagonist (76 +/- 7% and 47 +/- 2% block, respectively, at 1 microM). Dilation in response to sodium nitroprusside, an NO donor, was attenuated by 4-AP in vivo (41 +/- 6% block at 10 microg/min) and by correolide in vitro (29 +/- 4% block at 1 microM). K(V) current in smooth muscle cells was inhibited by 4-AP (IC(50) 1.1 +/- 0.1 mM) and virtually eliminated by correolide. Expression of mRNA for K(V)1 family members was detected in coronary arteries. Our data indicate that K(V) channels play an important role in regulating resting coronary blood flow, determining duration of reactive hyperemia, and mediating adenosine- and NO-induced vasodilation.
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Affiliation(s)
- Gregory M Dick
- Department of Exercise Physiology, Center for Interdisciplinary Research in Cardiovascular Sciences, West Virginia University School of Medicine, Morgantown, WV, USA
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Tavackoli S, Ashitkov T, Hu ZY, Motamedi M, Uretsky BF, Birnbaum Y. Simvastatin-induced myocardial protection against ischemia–reperfusion injury is mediated by activation of ATP-sensitive K+ channels. Coron Artery Dis 2004; 15:53-8. [PMID: 15201621 DOI: 10.1097/00019501-200402000-00008] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
OBJECTIVES Previous studies have suggested that the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors attenuate ischemia-reperfusion injury. We investigated whether pretreatment with simvastatin reduces myocardial infarct size and whether glyburide, a non-selective inhibitor of the ATP-sensitive K channels, abrogates this infarct size-limiting effect. METHODS Sprague-Dawley rats were treated with either simvastatin (20 mg/kg per day) or saline alone for 3 days. Additional groups of rats were treated as above and on the fourth day they received intravenous glyburide (0.3 mg/kg). All rats underwent 30 min of coronary artery occlusion followed by 180 min of reperfusion. Ischemic myocardium at risk was assessed with blue dye and infarct size with triphenyltetrazolium chloride. RESULTS Infarct size, expressed as a percentage of the myocardium at risk, was significantly smaller in the simvastatin group (n = 8, 20.8 +/- 3.4%) than in the placebo group (n = 6, 40.1 +/- 2.7%) (P = 0.001). Glyburide abolished the protective effect of simvastatin with infarct size being 34.2 +/- 6.9% and 29.7 +/- 3.9% of the area at risk in the simvastatin group (n = 7) and placebo (n = 7) group, respectively (P = 0.58). CONCLUSIONS Simvastatin significantly reduced myocardial infarct size. The protective effect was completely abrogated by glyburide, strongly suggesting that this protective effect is mediated via activation of the ATP-sensitive K channels.
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Affiliation(s)
- Shahin Tavackoli
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555-0553, USA
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Kavianipour M, Ronquist G, Wikström G, Waldenström A. Ischaemic preconditioning alters the energy metabolism and protects the ischaemic myocardium in a stepwise fashion. ACTA PHYSIOLOGICA SCANDINAVICA 2003; 178:129-37. [PMID: 12780387 DOI: 10.1046/j.1365-201x.2003.01108.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS AND METHODS Recently it was suggested that ischaemic preconditioning (IP) protects the myocardium in a graded pattern as assessed by myocardial infarct size estimation. Using tissue biopsies we investigated the impact of the proposed graded pattern of protection on myocardial energy state in an open-chest porcine model of IP with either one (1xIP) or four (4xIP) episodes of preconditioning. Furthermore, we evaluated the relationship between interstitial energy-related metabolite levels obtained by the microdialysis technique and the degree of subsequent ischaemic insult. RESULTS During the long ischaemia the difference between pre-ischaemic and post-ischaemic total adenylate pools and the sum of adenylate breakdown products (adenosine, inosine and hypoxanthine) as well as tissue lactate levels appeared as follows: non-IP > 1xIP > 4xIP (P < 0.05). Moreover interstitial peak levels of lactate, hypoxanthine and taurine displayed a graded pattern analogous to the development of ischaemic damage, where non-IP > 1xIP > 4xIP. CONCLUSIONS We present for the first time concordant energy metabolic and morphometric data in support of IP being a stepwise phenomenon for protection of the ischaemic myocardium. Furthermore, IP resulted in proportionally higher levels of hypoxanthine (relative to inosine) in the ischaemic myocardium, suggesting a different handling of adenine nucleotide breakdown products in the IP myocardium.
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Affiliation(s)
- M Kavianipour
- Department of Public Health and Clinical Medicine, Norrland University Hospital, Umeå, Sweden
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Fukuda H, Luo CS, Gu X, Guo L, Digerness SB, Li J, Pike MM. The effect of K(atp)channel activation on myocardial cationic and energetic status during ischemia and reperfusion: role in cardioprotection. J Mol Cell Cardiol 2001; 33:545-60. [PMID: 11181022 DOI: 10.1006/jmcc.2000.1328] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The role of cation and cellular energy homeostasis in ATP-sensitive K(+)(K(ATP)) channel-induced cardioprotection is poorly understood. To evaluate this, rapidly interleaved(23)Na and(31)P NMR spectra were acquired from isolated rat hearts exposed to direct K(ATP)channel activation from nicorandil or pinacidil. Nicorandil attenuated ATP depletion and intracellular Na(+)(Na(+)(i)) accumulation, delayed the progression of acidosis during zero-flow ischemia and prevented ischemic contracture. The K(ATP)channel inhibitor 5-hydroxydecanoate abolished these effects. Pinacidil did not alter Na(+)(i)accumulation, ATP depletion or pH during ischemia under the conditions employed. Both agonists greatly improved the post-ischemic functional recovery. Both agonists also dramatically improved the rate and extent of the reperfusion recoveries of Na(+)(i), PCr and ATP. The Na(+)(i)and PCr reperfusion recovery rates were tightly correlated, suggesting a causal relationship. Separate atomic absorption tissue Ca(2+)measurements revealed a marked reperfusion Ca(2+)uptake, which was reduced two-fold by pinacidil. In conclusion, these results clearly indicate that while K(ATP)channel-induced metabolic alterations can vary, the functional cardioprotection resulting from this form of pharmacological preconditioning does not require attenuation of acidosis, cellular energy depletion, or Na(+)(i)accumulation during ischemia. Rather than preservation of cationic/energetic status during ischemia, the cardioprotective processes may involve a preserved capability for its rapid restoration during reperfusion. The enhanced reperfusion Na(+)(i)recovery may be enabled by the improved reperfusion cellular energy state. This accelerated Na(+)(i)recovery could play an important cardioprotective role via a potential causal relationship with the reduction of reperfusion tissue Ca(2+)uptake and resultant reperfusion injury.
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Affiliation(s)
- H Fukuda
- University of Alabama at Birmingham, Department of Medicine, Division of Cardiovascular Disease, 703 19th Street South, Birmingham, AL 35294, USA
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