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Nielsen VG. Novel Toxicodynamic Model of Subcutaneous Envenomation to Characterize Snake Venom Coagulopathies and Assess the Efficacy of Site-Directed Inorganic Antivenoms. Int J Mol Sci 2023; 24:13939. [PMID: 37762243 PMCID: PMC10530349 DOI: 10.3390/ijms241813939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 08/31/2023] [Accepted: 09/03/2023] [Indexed: 09/29/2023] Open
Abstract
Venomous snake bite adversely affects millions of people yearly, but few animal models allow for the determination of toxicodynamic timelines with hemotoxic venoms to characterize the onset and severity of coagulopathy or assess novel, site-directed antivenom strategies. Thus, the goals of this investigation were to create a rabbit model of subcutaneous envenomation to assess venom toxicodynamics and efficacy of ruthenium-based antivenom administration. New Zealand White rabbits were sedated with midazolam via the ear vein and had viscoelastic measurements of whole blood and/or plasmatic coagulation kinetics obtained from ear artery samples. Venoms derived from Crotalus scutulatus scutulatus, Bothrops moojeni, or Calloselasma rhodostoma were injected subcutaneously, and changes in coagulation were determined over three hours and compared to samples obtained prior to envenomation. Other rabbits had ruthenium-based antivenoms injected five minutes after venom injection. Viscoelastic analyses demonstrated diverse toxicodynamic patterns of coagulopathy consistent with the molecular composition of the proteomes of the venoms tested. The antivenoms tested attenuated venom-mediated coagulopathy. A novel rabbit model can be used to characterize the onset and severity of envenomation by diverse proteomes and to assess site-directed antivenoms. Future investigation is planned involving other medically important venoms and antivenom development.
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Affiliation(s)
- Vance G Nielsen
- Department of Anesthesiology, The University of Arizona College of Medicine, Tucson, AZ 85724, USA
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Ono N, Suzuki S, Kawada K, Yamaguchi T, Azuma YT. Stress decreases contraction of the colon, and the effects of stress are different among the regions of the colon. J Vet Med Sci 2022; 84:1061-1064. [PMID: 35691932 PMCID: PMC9412072 DOI: 10.1292/jvms.22-0073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
Stress affects a variety of organs. Diarrhea and constipation are closely related to
stress, which involves the gastrointestinal motility of the colon. We compared the
gastrointestinal motility of the proximal, mid, and distal colon in mice with stress.
Stress was applied by water immersion restraint. Colon motility was measured using an
isotonic transducer in the direction of the circular muscles. Electric field
stimulation-induced contractions in stressed mice were reduced compared to control mice in
the proximal and distal colon. On the other hand, in the mid colon, contraction in control
mice and stressed mice were almost same. This interesting difference between the regions
may provide a clue to the functional abnormalities in gastrointestinal motility associated
with stress.
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Affiliation(s)
- Naoshige Ono
- Laboratory of Prophylactic Pharmacology, Osaka Metropolitan University Graduate School of Veterinary Science
| | - Sho Suzuki
- Laboratory of Prophylactic Pharmacology, Osaka Metropolitan University Graduate School of Veterinary Science
| | - Koichi Kawada
- Laboratory of Pharmacology, Faculty of Pharmaceutical Sciences, Chiba Institute of Science
| | - Taro Yamaguchi
- Laboratory of Pharmacology, Faculty of Pharmaceutical Sciences, Setsunan University
| | - Yasu-Taka Azuma
- Laboratory of Prophylactic Pharmacology, Osaka Metropolitan University Graduate School of Veterinary Science
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Liu R, Feng ZY, Li D, Jin B, Yan Lan, Meng LY. Recent trends in carbon-based microelectrodes as electrochemical sensors for neurotransmitter detection: A review. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116541] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Li Y, He R, Niu Y, Li F. Paper-Based Electrochemical Biosensors for Point-of-Care Testing of Neurotransmitters. JOURNAL OF ANALYSIS AND TESTING 2019. [DOI: 10.1007/s41664-019-00085-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Nishiyama K, Aono K, Fujimoto Y, Kuwamura M, Okada T, Tokumoto H, Izawa T, Okano R, Nakajima H, Takeuchi T, Azuma YT. Chronic kidney disease after 5/6 nephrectomy disturbs the intestinal microbiota and alters intestinal motility. J Cell Physiol 2018; 234:6667-6678. [PMID: 30317589 DOI: 10.1002/jcp.27408] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 08/21/2018] [Indexed: 12/11/2022]
Abstract
Organ-organ crosstalk is involved in homeostasis. Gastrointestinal symptoms are common in patients with renal failure. The aim of this study was to elucidate the relationship between gastrointestinal motility and gastrointestinal symptoms in chronic kidney disease. We performed studies in C57BL/6 mice with chronic kidney disease after 5/6 nephrectomy. Gastrointestinal motility was evaluated by assessing the ex vivo responses of ileum and distal colon strips to electrical field stimulation. Feces were collected from mice, and the composition of the gut microbiota was analyzed using 16S ribosomal RNA sequencing. Mice with chronic kidney disease after 5/6 nephrectomy showed a decreased amount of stool, and this constipation was correlated with a suppressed contraction response in ileum motility and decreased relaxation response in distal colon motility. Spermine, one of the uremic toxins, inhibited the contraction response in ileum motility, but four types of uremic toxins showed no effect on the relaxation response in distal colon motility. The 5/6 nephrectomy procedure disturbed the balance of the gut microbiota in the mice. The motility dysregulation and constipation were resolved by antibiotic treatments. The expression levels of interleukin 6, tumor necrosis factor-α, and iNOS in 5/6 nephrectomy mice were increased in the distal colon but not in the ileum. In addition, macrophage infiltration in 5/6 nephrectomy mice was increased in the distal colon but not in the ileum. We found that 5/6 nephrectomy altered gastrointestinal motility and caused constipation by changing the gut microbiota and causing colonic inflammation. These findings indicate that renal failure was remarkably associated with gastrointestinal dysregulation.
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Affiliation(s)
- Kazuhiro Nishiyama
- Laboratory of Veterinary Pharmacology, Division of Veterinary Science, Osaka Prefecture University Graduate School of Life and Environmental Science, Osaka, Japan
| | - Kimiya Aono
- Laboratory of Veterinary Pharmacology, Division of Veterinary Science, Osaka Prefecture University Graduate School of Life and Environmental Science, Osaka, Japan
| | - Yasuyuki Fujimoto
- Laboratory of Veterinary Pharmacology, Division of Veterinary Science, Osaka Prefecture University Graduate School of Life and Environmental Science, Osaka, Japan
| | - Mitsuru Kuwamura
- Laboratory of Veterinary Pathology, Division of Veterinary Science, Osaka Prefecture University Graduate School of Life and Environmental Science, Osaka, Japan
| | - Toshiya Okada
- Department of Laboratory Animal Science, Division of Veterinary Science, Osaka Prefecture University Graduate School of Life and Environmental Science, Osaka, Japan
| | - Hayato Tokumoto
- Laboratory of Bioscience and Biotechnology, Division of Biological Science, Osaka Prefecture University Graduate School of Science, Osaka, Japan
| | - Takeshi Izawa
- Laboratory of Veterinary Pathology, Division of Veterinary Science, Osaka Prefecture University Graduate School of Life and Environmental Science, Osaka, Japan
| | - Ryoichi Okano
- Laboratory of Separation Science and Engineering, Division of Chemical Engineering, Osaka Prefecture University Graduate School of Engineering, Osaka, Japan
| | - Hidemitsu Nakajima
- Laboratory of Veterinary Pharmacology, Division of Veterinary Science, Osaka Prefecture University Graduate School of Life and Environmental Science, Osaka, Japan
| | - Tadayoshi Takeuchi
- Laboratory of Veterinary Pharmacology, Division of Veterinary Science, Osaka Prefecture University Graduate School of Life and Environmental Science, Osaka, Japan
| | - Yasu-Taka Azuma
- Laboratory of Veterinary Pharmacology, Division of Veterinary Science, Osaka Prefecture University Graduate School of Life and Environmental Science, Osaka, Japan
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Nishiyama K, Morioka A, Kita S, Nakajima H, Iwamoto T, Azuma YT, Takeuchi T. Na/Ca(2+) exchanger 1 transgenic mice display increased relaxation in the distal colon. Pharmacology 2014; 94:230-8. [PMID: 25427675 DOI: 10.1159/000363246] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Accepted: 04/28/2014] [Indexed: 01/11/2023]
Abstract
Na(+)/Ca(2+) exchanger 1 (NCX1) is a plasma membrane transporter involved in regulating intracellular Ca(2+) concentrations. NCX1 is critical for Ca(2+) regulation in cardiac muscle, vascular smooth muscle and nerve fibers. However, little is known about the physiological role of NCX1 in gastrointestinal motility. To determine the role of NCX1 in gastrointestinal tissues, we examined electric field stimulation (EFS)-induced responses in the longitudinal smooth muscle of the distal colon in smooth muscle-specific NCX1 transgenic mice (Tg). Tg show that NCX1 protein was overexpressed in the distal colon at a level twofold greater than that of endogenous NCX1. We found that the amplitudes of EFS-induced relaxation that persisted during EFS were greater in Tg than in wild-type mice (WT). Under the nonadrenergic, noncholinergic condition, the EFS-induced relaxation in Tg was also greater than that in WT. Inhibition of NO synthase, CO synthase, soluble guanylate cyclase (sGC), and protein kinase G (PKG) all attenuated the enhanced relaxation in Tg, demonstrating the importance of NCX1 in NO/sGC/PKG signaling. The action of NOR-1, an NO donor, induced enhanced relaxation in Tg compared with that in WT. Unlike NOR-1, pituitary adenylate cyclase-activating peptide and vasoactive intestinal peptide induced a similar relaxation in Tg compared with that in WT. In this study, we demonstrate that NCX1 plays an important role in smooth muscle motility in the mouse distal colon.
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Affiliation(s)
- Kazuhiro Nishiyama
- Laboratory of Veterinary Pharmacology, Division of Veterinary Science, Osaka Prefecture University Graduate School of Life and Environmental Science, Osaka, Japan
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Nishiyama K, Azuma YT, Shintaku K, Yoshida N, Nakajima H, Takeuchi T. Evidence that Nitric Oxide Is a Non-Adrenergic Non-Cholinergic Inhibitory Neurotransmitter in the Circular Muscle of the Mouse Distal Colon: A Study on the Mechanism of Nitric Oxide-Induced Relaxation. Pharmacology 2014; 94:99-108. [DOI: 10.1159/000363191] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 04/25/2014] [Indexed: 11/19/2022]
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Nishiyama K, Azuma YT, Kita S, Azuma N, Hayashi S, Nakajima H, Iwamoto T, Takeuchi T. Na⁺/Ca²⁺ exchanger 1/2 double-heterozygote knockout mice display increased nitric oxide component and altered colonic motility. J Pharmacol Sci 2013; 123:235-45. [PMID: 24162024 DOI: 10.1254/jphs.13114fp] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The Na⁺/Ca²⁺ exchanger (NCX) is a plasma membrane transporter involved in regulating intracellular Ca²⁺ concentrations. NCX is critical for Ca²⁺ regulation in cardiac muscle, vascular smooth muscle, and nerve fibers. To determine the role of NCX1 and NCX2 in gastrointestinal tissues, we examined electric field stimulation (EFS)-induced responses in the longitudinal smooth muscle of the distal colon in NCX1 and NCX2 double-heterozygote knockoutmice (Double HET). We found that the amplitudes of EFS-induced relaxation that persisted during EFS were greater in Double HET than in wild-type mice (WT). Under the non-adrenergic, non-cholinergic (NANC) condition, EFS-induced relaxation in Double HET was similar in amplitude to that of WT. In the experiments in which l-NNA was added under NANC conditions following the EFS, the magnitudes of EFS-induced relaxation were smaller in Double HET than those in WT. In addition, an NCX inhibitor, SN-6, enhanced EFS-induced relaxation but did not affect EFS-induced relaxation under NANC condition, as in Double HET. Moreover, the magnitudes of relaxation induced by NOR-1, which generates NO, were greater in Double HET compared with WT. Similarly, SN-6 potentiated the magnitudes of NOR-1-induced relaxation. In this study, we demonstrate that NCX regulate colonic motility by altering the sensitivity of the inhibitory component.
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Affiliation(s)
- Kazuhiro Nishiyama
- Laboratory of Veterinary Pharmacology, Division of Veterinary Science, Osaka Prefecture University Graduate School of Life and Environmental Science, Japan
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Gibbons SJ, Verhulst PJ, Bharucha A, Farrugia G. Review article: carbon monoxide in gastrointestinal physiology and its potential in therapeutics. Aliment Pharmacol Ther 2013; 38:689-702. [PMID: 23992228 PMCID: PMC3788684 DOI: 10.1111/apt.12467] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 05/03/2013] [Accepted: 08/07/2013] [Indexed: 12/14/2022]
Abstract
BACKGROUND While carbon monoxide (CO) is a known toxin, it is now recognised that CO is also an important signalling molecule involved in physiology and pathophysiology. AIMS To summarise our current understanding of the role of endogenous CO in the regulation of gastrointestinal physiology and pathophysiology, and to potential therapeutic applications of modulating CO. METHODS This review is based on a comprehensive search of the Ovid Medline comprehensive database and supplemented by our ongoing studies evaluating the role of CO in gastrointestinal physiology and pathophysiology. RESULTS Carbon monoxide derived from haem oxygenase (HO)-2 is predominantly involved in neuromodulation and in setting the smooth muscle membrane potential, while CO derived from HO-1 has anti-inflammatory and antioxidative properties, which protect gastrointestinal smooth muscle from damage caused by injury or inflammation. Exogenous CO is being explored as a therapeutic agent in a variety of gastrointestinal disorders, including diabetic gastroparesis, post-operative ileus, organ transplantation, inflammatory bowel disease and sepsis. However, identifying the appropriate mechanism for safely delivering CO in humans is a major challenge. CONCLUSIONS Carbon monoxide is an important regulator of gastrointestinal function and protects the gastrointestinal tract against noxious injury. CO is a promising therapeutic target in conditions associated with gastrointestinal injury and inflammation. Elucidating the mechanisms by which CO works and developing safe CO delivery mechanisms are necessary to refine therapeutic strategies.
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Affiliation(s)
- S J Gibbons
- Enteric NeuroScience Program, Mayo Clinic, Rochester, MN 55905, USA
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Hemin and Zinc Protoporphyrin IX Affect Granisetron Constipating Effects In Vitro and In Vivo. ISRN GASTROENTEROLOGY 2013; 2013:612037. [PMID: 23864955 PMCID: PMC3705784 DOI: 10.1155/2013/612037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Accepted: 06/05/2013] [Indexed: 12/20/2022]
Abstract
Granisetron is a 5-HT3 receptors antagonist used in the management of emesis associated with anticancer chemotherapy. It affects intestinal motility with constipating effect. Since the pathway heme oxygenase/carbon monoxide (HO/CO) is involved in gastrointestinal motility, we evaluated the possible interplay between granisetron and agents affecting HO/CO pathways such as zinc protoporphyrin IX (ZnPPIX), an HO inhibitor, or hemin, an HO-1 inducer. ZnPPIX (10 µM) or hemin (10 µM), but not granisetron (0.1, 0.3, 1 µM), affected spontaneous basal activity recorded in rat duodenal strips, in noncholinergic nonadrenergic conditions. Granisetron restored spontaneous basal activity after ZnPPIX, but not after hemin. ZnPPIX decreased and hemin increased the inhibition of activity after electrical field stimulation (EFS), but they did not affect the contraction that follows the relaxation induced by EFS called off contraction. Granisetron did not alter the response to EFS per se but abolished both ZnPPIX and hemin effect when coadministered. In vivo study showed constipating effect of granisetron (25, 50, 75 µg/kg/sc) but no effect of either ZnPPIX (50 µg/kg/i.p.) or hemin (50 µM/kg/i.p.). When coadministered, granisetron effect was abolished by ZnPPIX and increased by hemin. Specimens from rats treated in vivo with hemin (50 µM/kg/i.p.) showed increased HO-1 protein levels. In conclusion, granisetron seems to interact with agents affecting HO/CO pathway both in vitro and in vivo.
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COSYNS SMR, DHAESE I, THOONEN R, BUYS ES, VRAL A, BROUCKAERT P, LEFEBVRE RA. Heme deficiency of soluble guanylate cyclase induces gastroparesis. Neurogastroenterol Motil 2013; 25:e339-52. [PMID: 23551931 PMCID: PMC4932850 DOI: 10.1111/nmo.12120] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 02/27/2013] [Indexed: 12/24/2022]
Abstract
BACKGROUND Soluble guanylate cyclase (sGC) is the principal target of nitric oxide (NO) to control gastrointestinal motility. The consequence on nitrergic signaling and gut motility of inducing a heme-free status of sGC, as induced by oxidative stress, was investigated. METHODS sGCβ1 (H105F) knock-in (apo-sGC) mice, which express heme-free sGC that has basal activity, but cannot be stimulated by NO, were generated. KEY RESULTS Diethylenetriamine NONOate did not increase sGC activity in gastrointestinal tissue of apo-sGC mice. Exogenous NO did not induce relaxation in fundic, jejunal and colonic strips, and pyloric rings of apo-sGC mice. The stomach was enlarged in apo-sGC mice with hypertrophy of the muscularis externa of the fundus and pylorus. In addition, gastric emptying and intestinal transit were delayed and whole-gut transit time was increased in the apo-sGC mice, while distal colonic transit time was maintained. The nitrergic relaxant responses to electrical field stimulation at 1-4 Hz were abolished in fundic and jejunal strips from apo-sGC mice, but in pyloric rings and colonic strips, only the response at 1 Hz was abolished, indicating the contribution of other transmitters than NO. CONCLUSIONS & INFERENCES The results indicate that the gastrointestinal consequences of switching from a native sGC to a heme-free sGC, which cannot be stimulated by NO, are most pronounced at the level of the stomach establishing a pivotal role of the activation of sGC by NO in normal gastric functioning. In addition, delayed intestinal transit was observed, indicating that nitrergic activation of sGC also plays a role in the lower gastrointestinal tract.
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Affiliation(s)
- S. M. R. COSYNS
- Heymans Institute of Pharmacology, Ghent University, Ghent, Belgium
| | - I. DHAESE
- Heymans Institute of Pharmacology, Ghent University, Ghent, Belgium
| | - R. THOONEN
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium,Tufts Medical Center, Molecular Cardiology Research Center, Boston, MA, USA
| | - E. S. BUYS
- Anesthesia Center for Critical Care Research, Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - A. VRAL
- Department of Medical Basic Sciences, Ghent University, Ghent, Belgium
| | - P. BROUCKAERT
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - R. A. LEFEBVRE
- Heymans Institute of Pharmacology, Ghent University, Ghent, Belgium
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Azuma YT, Nishiyama K, Kita S, Komuro I, Nakajima H, Iwamoto T, Takeuchi T. Na(+) /Ca(2+) exchanger 2-heterozygote knockout mice display decreased acetylcholine release and altered colonic motility in vivo. Neurogastroenterol Motil 2012; 24:e600-10. [PMID: 23072505 DOI: 10.1111/nmo.12029] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND The Na(+) /Ca(2+) exchanger (NCX) is a plasma membrane transporter involved in regulating intracellular Ca(2+) concentrations. NCX is critical for Ca(2+) regulation in cardiac muscle, vascular smooth muscle, and nerve fibers. However, little is known about the physiological role of NCX in the myenteric neurons and smooth muscles of the gastrointestinal tract. METHODS To determine the role of NCX1 and NCX2 in gastrointestinal tissues, we examined electric field stimulation (EFS)-induced responses in the longitudinal smooth muscle of the distal colon in NCX1- and NCX2-heterozygote knockout mice. KEY RESULTS We found that the amplitudes of EFS-induced relaxation that persisted during EFS were greater in NCX2 heterozygous mice (HET) than in wild-type mice (WT). Under the nonadrenergic, noncholinergic (NANC) condition, EFS-induced relaxation in NCX2 HET was similar in amplitude to that of WT. In addition, an NCX inhibitor, YM-244769 enhanced EFS-induced relaxation but did not affect EFS-induced relaxation under the NANC condition, as in NCX2 HET. Unlike NCX2 HET, NCX1 HET displayed no marked changes in colonic motility. These results indicate that cholinergic function in the colon is altered in NCX2 HET. The magnitude of acetylcholine (ACh)-induced contraction in NCX2 HET was similar to that in WT. In contrast, EFS-induced ACh release was reduced in NCX2 HET compared with that in WT. CONCLUSIONS & INFERENCES In this study, we demonstrate that NCX2 regulates colonic motility by altering ACh release onto the myenteric neurons of the distal colon.
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Affiliation(s)
- Y T Azuma
- Laboratory of Veterinary Pharmacology, Division of Veterinary Science, Osaka Prefecture University Graduate School of Life and Environmental Science, Osaka, Japan.
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De Benedictis L, Potenza MA, Gagliardi S, Zigrino A, Montagnani M, De Salvia MA. Rosiglitazone reverses increased duodenal inhibitory response in spontaneously hypertensive rats. Neurogastroenterol Motil 2012; 24:e56-66. [PMID: 21995307 DOI: 10.1111/j.1365-2982.2011.01798.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND Thiazolidinediones (TZDs) including rosiglitazone (ROSI) are insulin sensitizing agents with beneficial gastrointestinal effects. However, no studies are available on TZDs effect in gastrointestinal motility. We evaluated the effects of ROSI on gastrointestinal inhibitory neurotransmission focusing on the modulatory roles of nitric oxide synthase/nitric oxide (NOS/NO) and heme oxygenase/carbon monoxide (HO/CO) pathways. METHODS Spontaneously hypertensive rats (SHR) were used as model of insulin resistance. Duodenal strips were obtained from vehicle-treated SHR, ROSI-treated SHR (5 mg kg(-1) by gavage daily per 6 weeks), and Wistar Kyoto (WKY). Inhibitory responses to electrical field stimulation (EFS) were evaluated in the presence of HO inhibitor zinc protoporphyrin IX (ZnPPIX, 10 μmol L(-1)) or NOS inhibitor N(G)-nitro-L-arginine (L-NNA, 100 μmol L(-1)), alone and in combination. Protein levels of HO and NOS isoforms were evaluated by immunohistochemistry and western blot analysis. KEY RESULTS Basal responses to EFS were significantly increased in duodenum strips from vehicle-treated SHR vs WKY. This effect was reversed in ROSI-treated SHR. The EFS-mediated relaxation was comparably reduced by ZnPPIX in WKY and SHR, but not in ROSI-treated SHR animals. The L-NNA reduced EFS response to a similar extent in WKY and ROSI -treated SHR, but its effect was significantly higher in vehicle-treated SHR. Expression of HO-1 protein was significantly lower, whereas HO-2 protein levels were unchanged in ROSI-treated SHR with respect to vehicle-treated SHR. Finally, increased levels of nNOS in vehicle-treated SHR were reduced in ROSI-treated SHR. CONCLUSIONS & INFERENCES Chronic ROSI treatment reverses increased SHR duodenal inhibitory response acting on CO and NO components.
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Affiliation(s)
- L De Benedictis
- Department of Biomedical Sciences and Human Oncology, Medical School, University of Bari Aldo Moro, Bari, Italy
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Yoshioka Y, Takeda N, Yamamuro A, Kasai A, Maeda S. Nitric oxide inhibits lipopolysaccharide-induced inducible nitric oxide synthase expression and its own production through the cGMP signaling pathway in murine microglia BV-2 cells. J Pharmacol Sci 2010; 113:153-60. [PMID: 20484865 DOI: 10.1254/jphs.10060fp] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
The present study examined the effect of the nitric oxide (NO) donor NOC18 on lipopolysaccharide (LPS)-induced NO production to investigate a regulation mechanism of NO production by microglial cells. LPS increased the levels of NO and inducible NO synthase (iNOS) protein in BV-2 murine microglial cells in a concentration-dependent manner. Pretreatment with NOC18 for 24 h concentration-dependently attenuated the LPS-induced iNOS protein expression and NO production. The inhibitory effect of NOC18 on LPS-induced NO production was partially blocked by LY83583, a soluble guanylate cyclase inhibitor. Pretreatment with dibutyryl guanosine-3',5'-cyclic monophosphate (DBcGMP), a cell-permeable cGMP analogue, for 24 h attenuated partially LPS-induced iNOS protein expression and NO production. Furthermore, the effects of LPS on iNOS and NO production were inhibited by the c-Jun N-terminal kinase (JNK) inhibitor SP600125, and LPS-induced phosphorylation of JNK and c-Jun was inhibited by NOC18 and DBcGMP. These results suggest that NO production by microglial cells is controlled by a negative feedback mechanism via the NO/cGMP signaling pathway.
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Affiliation(s)
- Yasuhiro Yoshioka
- Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Setsunan University, Hirakata, Osaka, Japan
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