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Li S, Yang M, Shi Y, Li J, Liu C. Downregulation of mesenteric afferent sensitivity following long-term systemic treatment of vincristine in mice. Toxicol Appl Pharmacol 2024; 484:116887. [PMID: 38458354 DOI: 10.1016/j.taap.2024.116887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 02/21/2024] [Accepted: 03/03/2024] [Indexed: 03/10/2024]
Abstract
AIMS Gastrointestinal paresthesia and dysmotility are common side effects of vincristine (VCR) chemotherapy, which have become one of the factors for dose reduction, therapy delay or discontinuation. However, the mechanism is not entirely clear, whether it is related to autonomic nerves injury remains unknown. Therefore, we aimed to study whether VCR-induced gastrointestinal toxicity is related to changes in mesenteric afferent activity. METHODS The effects of a single VCR stimulation and long-term systemic VCR treatment on mesenteric afferent activity were investigated by directly recording mesenteric afferent discharge in vitro. RESULTS Our results showed that a single VCR (0.001-1 μmol/L) stimulation obviously increased the spontaneous, chemically evoked and mechanically evoked discharge of jejunal and colonic mesenteric afferents. This kind of hypersensitivity of VCR could be blocked by capsazepine, a transient receptor potential vanilloid 1 (TRPV1) antagonist. For the mice treated with VCR (0.1 mg/kg/d, i.p.) for 14 days, the abdominal withdrawal reflex and writhing response scores were reduced. Meanwhile, the spontaneous discharge of colonic mesenteric afferents and the afferent response to VCR was downregulated, and the afferent sensitivity to chemical and mechanical stimulation was reduced. Moreover, the expression of TRPV1 in colon was decreased. CONCLUSIONS These results suggest that the direct stimulation by VCR increases the mesenteric afferent sensitivity by activating TRPV1, which may be the reason of VCR-induced abdominal pain; the long-term systemic treatment of VCR decreases mesenteric afferent sensitivity by reducing TRPV1, which may be the reason of VCR-induced constipation.
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Affiliation(s)
- Shuang Li
- Department of Physiology, School of Basic Medical Sciences, Cheeloo Medical College, Shandong University, 44 Wenhua Xi Road, Jinan, Shandong 250012, China
| | - Mengyuan Yang
- Department of Physiology, School of Basic Medical Sciences, Cheeloo Medical College, Shandong University, 44 Wenhua Xi Road, Jinan, Shandong 250012, China
| | - Yao Shi
- Ministry of Education Key Laboratory of Protein, School of Life Sciences, Tsinghua University, 30 Shuang Qing Road, Beijing 100084, China
| | - Jingxin Li
- Department of Physiology, School of Basic Medical Sciences, Cheeloo Medical College, Shandong University, 44 Wenhua Xi Road, Jinan, Shandong 250012, China
| | - Chuanyong Liu
- Department of Physiology, School of Basic Medical Sciences, Cheeloo Medical College, Shandong University, 44 Wenhua Xi Road, Jinan, Shandong 250012, China; Provincial Key Lab of Mental Disorders, Shandong University, 44 Wenhua Xi Road, Jinan, Shandong 250012, China.
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Bao L, Zhao J, Gregersen H. Association between jejunal remodeling in fasting rats and hypersensitivity of intestinal afferent nerves to mechanical stimulation. Biomech Model Mechanobiol 2024; 23:73-86. [PMID: 37548873 DOI: 10.1007/s10237-023-01758-7] [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: 02/18/2023] [Accepted: 07/24/2023] [Indexed: 08/08/2023]
Abstract
Remodeling of Intestinal properties and hypersensitivity of intestinal afferents to mechanical stimulation were previously demonstrated in a fasting rat model. Other studies investigated the association between mechanical and histological remodeling during fasting. This study aimed to further explore the relationship between the jejunal remodeling and intestinal afferent hypersensitivity by combining afferent nerve recordings with histological and mechanical data. Eight male Sprague Dawley rats had no access to food for 7 days (Fasting group). Seven male rats served as controls (Control group). Jejunal segments were studied in vitro in an organ bath for analysis of afferent signaling and for analysis of mechanical and histomorphological parameters. Correlation analyses were done to analyze association between nerve activity (spike rate increase ratio, SRIR) at distension levels of 20, 40 and 80 cmH2O and mechanical stress and histomorphological changes of the jejunal segments. Compared with the Control group, the main findings in jejunal segments in the Fasting group were (1) Most histomorphometry parameters were reduced (P < 0.05-P < 0.001), (2) SRIR values were higher (P < 0.001), (3) The relative numbers of intermuscular and submucosal neurons were increased (P < 0.05-P < 0.01), and (4) SRIR was negatively correlated with intestinal wall thickness, circumferential muscle layer thickness and positively correlated with the inner residual strain, the number of neurons, and the mechanical stress. In conclusion, the fasting-induced histomorphological remodeling (reduced wall thickness and increased relative number of neurons) and biomechanical remodeling (residual strain changes and high stress level) of the intestine in fasting rats were associated with hypersensitivity of intestinal afferents. Afferent hypersensitivity appears to be dependent on stress rather than on strain.
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Affiliation(s)
- Lingxia Bao
- Chongqing University of Posts and Telecommunications, Chongqing, 400065, China
- GIOME and the Key Laboratory for Biorheological Science and Technology of Ministry of Education, College of Bioengineering at Chongqing University, Chongqing, 400044, China
| | - Jingbo Zhao
- GIOME and the Key Laboratory for Biorheological Science and Technology of Ministry of Education, College of Bioengineering at Chongqing University, Chongqing, 400044, China.
- Anbiping (Chongqing) Pathological Diagnosis Center, No. 8 Xiyuan North Road, Shapingba District, Chongqing, 401334, China.
| | - Hans Gregersen
- GIOME and the Key Laboratory for Biorheological Science and Technology of Ministry of Education, College of Bioengineering at Chongqing University, Chongqing, 400044, China
- GIOME, California Medical Innovations Institute, San Diego, CA, USA
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Aslan I, Tarhan Celebi L, Kayhan H, Kizilay E, Gulbahar MY, Kurt H, Cakici B. Probiotic Formulations Containing Fixed and Essential Oils Ameliorates SIBO-Induced Gut Dysbiosis in Rats. Pharmaceuticals (Basel) 2023; 16:1041. [PMID: 37513952 PMCID: PMC10383999 DOI: 10.3390/ph16071041] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 07/13/2023] [Accepted: 07/19/2023] [Indexed: 07/30/2023] Open
Abstract
Dysbiosis of the gut microbiota is associated with the pathogenesis of intestinal diseases such as inflammatory bowel disease, irritable bowel syndrome (IBS), small intestinal bacterial overgrowth (SIBO), and metabolic disease states such as allergies, cardiovascular diseases, obesity, and diabetes. SIBO is a condition characterized by an increased number (>1 × 103 CFU) of abnormal bacterial species in the small intestine. Interest in SIBO has gained importance due to increased awareness of the human microbiome and its potential relationships with human health and disease, which has encouraged new work in this area. In recent years, standard antibiotic regimens (rifaximin and metronidazole) have been used to treat SIBO, but solo antibiotics or their derivatives are insufficient. In this study, the therapeutic effects of the probiotic form, which contains coconut oil and traces of peppermint-lemon-patchouli essential oil, were evaluated on the Dysbiosis-Based Rat SIBO Model. There are significant differences between sick and healthy rats (p = 0.014), between sick rats and rats treated with the oil mix plus probiotic mix protocol (p = 0.026), and between rats treated with only the probiotic and only oil protocols (p = 0.030) in the evaluation of TNF-α levels. Histologically, villi distortion and loss of crypts, epithelial shedding and necrotic changes in the apical regions of the villi, and inflammatory cell infiltrations extending to the lamina propria and submucosa were observed in sick rats. Mitotic figures in villus epithelium and crypts were observed in rats treated with 9.2 × 109 CFU/1000 mg/coconut oil + trace amounts of peppermint-lemon-patchouli essential oil and a probiotic mixture (oil + probiotic mix protocol). A regression of inflammatory reactions and an increase in goblet cells were observed. A decrease was observed in inflammation markers in sick rats. On the other hand, the oil plus probiotic mix protocol recovered digestive system defects in the animals caused by dysbiosis. In the future, these treatment approaches can be effective in the treatment of SIBO.
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Affiliation(s)
- Ismail Aslan
- Department of Pharmaceutical Technology, Hamidiye Faculty of Pharmacy, University of Health Sciences, İstanbul 34668, Turkey
- SFA R&D and Analysis Services, Teknopark İstanbul, İstanbul 34906, Turkey
- ATA BIO Technologies, Teknopol İstanbul, İstanbul 34930, Turkey
| | - Leyla Tarhan Celebi
- SFA R&D and Analysis Services, Teknopark İstanbul, İstanbul 34906, Turkey
- ATA BIO Technologies, Teknopol İstanbul, İstanbul 34930, Turkey
| | - Hulya Kayhan
- Art de Huile, Teknopol İstanbul, İstanbul 34930, Turkey
| | - Emine Kizilay
- Hamidiye Vocational School of Health Services, University of Health Sciences, İstanbul 34668, Turkey
| | - Mustafa Yavuz Gulbahar
- Department of Pathology, Faculty of Veterinary Medicine, Ondokuz Mayıs University, Samsun 55200, Turkey
| | - Halil Kurt
- Department of Medical Biology, Hamidiye International Faculty of Medicine, University of Health Sciences, İstanbul 34668, Turkey
| | - Bekir Cakici
- SFA R&D and Analysis Services, Teknopark İstanbul, İstanbul 34906, Turkey
- ATA BIO Technologies, Teknopol İstanbul, İstanbul 34930, Turkey
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Cai H, Xiao Y, Chen S, Lu Y, Du J, You Y, Zhu J, Zhou J, Cai W, Wang Y. Heterozygous Actg2 R257C mice mimic the phenotype of megacystis microcolon intestinal hypoperistalsis syndrome. Neurogastroenterol Motil 2023; 35:e14472. [PMID: 36264152 DOI: 10.1111/nmo.14472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 07/27/2022] [Accepted: 09/08/2022] [Indexed: 01/01/2023]
Abstract
BACKGROUND Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) is a rare and serious congenital disorder with poor outcomes, where a heterozygous missense mutation is present in the ACTG2 gene. Here, we aimed to investigate the pathogenesis of ACTG2 in MMIHS. METHODS A cohort with 20 patients with MMIHS was screened. Actg2R257C heterozygous mutant mice were generated using the CRISPR/Cas9 system. Gastrointestinal (GI) motility, voluntary urination, collagen gel contraction, and G-actin/F-actin analysis were performed. KEY RESULTS The R257C variant of ACTG2 most frequently occurred in patients with MMIHS and demonstrated the typical symptoms of MMIHS. Actg2R257C heterozygous mutant mice had dilated intestines and bladders. The functional assay showed a prolonged total time of GI transit and decreased urine spot area. Collagen gel contraction assay and G-actin/F-actin analysis indicated that mutant mice showed reduced area of contraction of smooth muscle cells (SMCs) and impaired actin polymerization. CONCLUSIONS & INFERENCES A mouse model demonstrating MMIHS-like symptoms was generated. The Actg2R257C heterozygous variant impairs SMCs contraction by interfering with actin polymerization, leading to GI motility disorders.
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Affiliation(s)
- Hui Cai
- Division of Pediatric Gastroenterology and Nutrition, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yongtao Xiao
- Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China.,Shanghai Institute of Pediatric Research, Shanghai, China
| | - Shanshan Chen
- Division of Pediatric Gastroenterology and Nutrition, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Ying Lu
- Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China.,Shanghai Institute of Pediatric Research, Shanghai, China
| | - Jun Du
- Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China.,Shanghai Institute of Pediatric Research, Shanghai, China
| | - Yaying You
- Division of Pediatric Gastroenterology and Nutrition, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Jing Zhu
- Shanghai Institute of Pediatric Research, Shanghai, China
| | - Jie Zhou
- Division of Pediatric Gastroenterology and Nutrition, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Wei Cai
- Division of Pediatric Gastroenterology and Nutrition, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China.,Shanghai Institute of Pediatric Research, Shanghai, China
| | - Ying Wang
- Division of Pediatric Gastroenterology and Nutrition, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China.,Shanghai Institute of Pediatric Research, Shanghai, China
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Zhao J, Liao D, Gregersen H. Mechanical analysis of intestinal contractility in a neonatal maternal deprivation irritable bowel syndrome rat model. J Biomech 2019; 93:42-51. [PMID: 31213281 DOI: 10.1016/j.jbiomech.2019.06.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 06/05/2019] [Accepted: 06/05/2019] [Indexed: 02/07/2023]
Abstract
The aims of the present study are to investigate biomechanical properties and provide mechanical analysis of contractility in ileum and colon in a neonatal maternal deprivation (NMD) irritable bowel syndrome (IBS) rat model. Mechanical testing was done on segments from ileum and colon in 25 IBS rats and 13 Control rats. Morphometric data were obtained from digitized images of the segments at no-load and zero-stress states. Pressure and diameter changes were measured during flow and ramp distensions under active and passive experimental conditions. Circumferential stresses (force per area) and strains (deformation) were computed with referenced to the zero-stress state. The contraction frequency was analyzed. Contraction thresholds and maximum contraction amplitude were calculated in terms of mechanical stress and strain. Compared with controls, the IBS rats had lower body weight (P < 0.01), smaller colonic opening angle (P < 0.05), higher colonic contraction frequency (P < 0.05 and P < 0.01) and lower contraction thresholds of pressure, stress and strain in both ileum and colon (P < 0.05 and P < 0.01). The maximum contraction pressure, stress and strain did not differ between IBS and Control groups (P > 0.05). In conclusion, the pressure, stress, and strain to evoke contractility in ileum and colon were lower whereas the frequency of induced colon contractions was higher in NMD IBS rats compared to normal rats. Furthermore, zero-stress state remodeling occur in colon in NMD IBS rats. Further studies on the association between intestinal biomechanical properties, hypersensitivity and afferent signaling in the IBS animal models are warranted.
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Affiliation(s)
- Jingbo Zhao
- GIOME Academia, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Mech-Sense, Department of Gastroenterology, Aalborg University Hospital, Aalborg, Denmark.
| | - Donghua Liao
- GIOME Academia, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Mech-Sense, Department of Gastroenterology, Aalborg University Hospital, Aalborg, Denmark
| | - Hans Gregersen
- GIOME, Department of Surgery, Prince of Wales Hospital and Chinese University of Hong Kong, Hong Kong Special Administrative Region
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Xu X, Li S, Shi Y, Tang Y, Lu W, Han T, Xue B, Li J, Liu C. Hydrogen sulfide downregulates colonic afferent sensitivity by a nitric oxide synthase-dependent mechanism in mice. Neurogastroenterol Motil 2019; 31:e13471. [PMID: 30230133 DOI: 10.1111/nmo.13471] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Revised: 08/04/2018] [Accepted: 08/24/2018] [Indexed: 02/01/2023]
Abstract
BACKGROUND The effect of hydrogen sulfide (H2 S) on visceral nociception is elusive. The conflicting evidence of its pro- and antinociceptive effects raises a series of questions with respect to the effect of H2 S on colonic afferent activity and the underlying mechanism, which was further elucidated in this study. METHODS Colonic mesenteric afferent nerve spikes of normal male C57BL/6J mice, Cbs+/- mice, and Wistar rats were recorded in vitro. The abdominal withdrawal reflex (AWR) induced by colorectal distension (CRD) was evaluated in Cbs+/- mice and WT littermates. KEY RESULTS Sodium hydrosulfide (NaHS) significantly decreased colonic afferent spontaneous discharge, chemosensitivity to bradykinin, mechanosensitivity to ramp distention, and intraluminal pressure in mice. Reducing the relaxant action of NaHS on intestinal smooth muscle using the nonspecific K+ channel blocker TEA (10 mmol/L) did not block the inhibition of NaHS on afferent nerve activity. The inhibitory effects of NaHS (0.5 mmol/L) on colonic afferent sensitivity were largely eliminated by the pretreatment with nonspecific NOS inhibitor NG -Methyl-l-arginine acetate salt (1 mmol/L), the specific nNOS inhibitor NPLA (1 μmol/L), or N-type Ca2+ channel blocker ω-conotoxin GVIA (1 μmol/L). Compared with WT mice, Cbs+/- mice showed increased mesenteric afferent sensitivity to colonic distention and enhanced hyperalgesic response to CRD. Intraperitoneal administration of NaHS (60 μmol/kg) alleviated the nociception response to CRD in both Cbs+/- and WT mice. CONCLUSIONS AND INFERENCES H2 S downregulates colonic mesenteric afferent sensitivity by a nNOS-dependent mechanism in mice. Our findings may demonstrate a new mechanism for the antinociceptive effect of H2 S in colon.
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Affiliation(s)
- Xiaomeng Xu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Shandong University Cheeloo Medical College, Shandong, China
| | - Shuang Li
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Shandong University Cheeloo Medical College, Shandong, China
| | - Yao Shi
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Shandong University Cheeloo Medical College, Shandong, China
| | - Yan Tang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Shandong University Cheeloo Medical College, Shandong, China
| | - Wen Lu
- College of Agricultural and Biological Engineering, Heze University, Shandong, China
| | - Ting Han
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Shandong University Cheeloo Medical College, Shandong, China
| | - Bing Xue
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Shandong University Cheeloo Medical College, Shandong, China
| | - Jingxin Li
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Shandong University Cheeloo Medical College, Shandong, China
| | - Chuanyong Liu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Shandong University Cheeloo Medical College, Shandong, China.,Provincial Key Lab of Mental Disorder, School of Basic Medical Sciences, Shandong University Cheeloo Medical College, Shandong, China
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Time-Dependent Alterations of Gut Wall Integrity in Small Bowel Obstruction in Mice. J Surg Res 2019; 233:249-255. [DOI: 10.1016/j.jss.2018.07.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 06/18/2018] [Accepted: 07/13/2018] [Indexed: 01/01/2023]
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Yu Y, Park SJ, Beyak MJ. Inducible nitric oxide synthase-derived nitric oxide reduces vagal satiety signalling in obese mice. J Physiol 2018; 597:1487-1502. [PMID: 30565225 DOI: 10.1113/jp276894] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 11/19/2018] [Indexed: 12/22/2022] Open
Abstract
KEY POINTS Obesity is associated with disrupted satiety regulation. Mice with diet-induced obesity have reduced vagal afferent neuronal excitability and a decreased afferent response to satiety signals. A low grade inflammation occurs in obesity with increased expression of inducible nitric oxide synthase (iNOS). Inhibition of iNOS in diet-induced obese mice restored vagal afferent neuronal excitability, increased the afferent response to satiety mediators and distention of the gut, and reduced short-term energy intake. A prolonged inhibition of iNOS reduced energy intake and body weight gain during the first week, and reduced amounts of epididymal fat after 3 weeks. We identified a novel pathway underlying disrupted satiety regulation in obesity. Blocking of this pathway might be clinically useful for the management of obesity. ABSTRACT Vagal afferents regulate feeding by transmitting satiety signals to the brain. Mice with diet-induced obesity have reduced vagal afferent sensitivity to satiety signals. We investigated whether inducible nitric oxide synthase (iNOS)-derived NO contributed to this reduction. C57BL/6J mice were fed a high- or low-fat diet for 6-8 weeks. Nodose ganglia and jejunum were analysed by immunoblotting for iNOS expression; NO production was measured using a fluorometric assay. Nodose neuron excitability and intestinal afferent sensitivity were evaluated by whole-cell patch clamp and in vitro afferent recording, respectively. Expression of iNOS and production of NO were increased in nodose ganglia and the small intestine in obese mice. Inhibition of iNOS in obese mice by pre-treatment with an iNOS inhibitor increased nodose neuron excitability via 2-pore-domain K+ channel leak currents, restored afferent sensitivity to satiety signals and reduced short-term energy intake. Obese mice given the iNOS inhibitor daily for 3 weeks had reduced energy intake and decreased body weight gain during the first week, compared to mice given saline, and lower amounts of epididymal fat at the end of 3 weeks. Inhibition of iNOS or blocking the action of iNOS-derived NO on vagal afferent pathways might comprise therapeutic strategies for hyperphagia and obesity.
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Affiliation(s)
- Yang Yu
- Gastrointestinal Disease Research Unit, Kingston General Hospital, Queen's University, Kingston, ON, Canada
| | - Sung Jin Park
- Gastrointestinal Disease Research Unit, Kingston General Hospital, Queen's University, Kingston, ON, Canada
| | - Michael J Beyak
- Gastrointestinal Disease Research Unit, Kingston General Hospital, Queen's University, Kingston, ON, Canada
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Tawfik DI, Osman AS, Tolba HM, Khattab A, Abdel-Salam LO, Kamel MM. Evaluation of therapeutic effect of low dose naltrexone in experimentally-induced Crohn's disease in rats. Neuropeptides 2016; 59:39-45. [PMID: 27392602 DOI: 10.1016/j.npep.2016.06.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 06/17/2016] [Accepted: 06/20/2016] [Indexed: 12/25/2022]
Abstract
BACKGROUND AND AIM Crohn's disease is a relapsing inflammatory condition afflicting the digestive tract. Drugs used for treatment of Crohn's disease may be associated with serious side effects. Endogenous opioid peptides modulate inflammatory cytokine production. Opioid antagonists have been shown to play a role in healing and repair of tissues. This work was designed to detect the possible beneficial effects of opioid antagonist naltrexone in indomethacin-induced Crohn's disease in rats. EXPERIMENTAL APPROACH Enteritis was induced in male albino rats by two subcutaneous injection of indomethacin in a dose of 7.5mg/kg 24h apart started on day one. Salfasalazine, naltrexone and their combination were administered orally from day one of induction of enteritis to day 10. Disease activity index, serum levels of C-reactive protein and tumor necrosis factor-α, macroscopic and microscopic pathological scores and in vitro motility studies were evaluated. RESULTS Induction of enteritis resulted in significant increase of disease activity index, significant elevation of serum levels of C-reactive protein and tumor necrosis factor-α, significant deterioration of pathological scores and significant increase in the mean contractility response of the isolated ileal segments compared with normal untreated rats. Treatment with sulfasalazine, low dose of natrexone or their combination resulted in significant improvement of all measured parameters compared with enteritis group. CONCLUSION The current finding could provide new interesting opportunity for developing new therapeutic approaches for treatment of Crohn's disease. Use of naltrexone, especially in small dose, has little side effects making it of interest for treatment of Crohn's disease. Also, it provides the possibility of reduced doses of other drugs if it is used as combined therapy.
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Affiliation(s)
| | - Afaf Sayed Osman
- Medical Pharmacology Department, Faculty of Medicine, Cairo University, Eqypt.
| | | | - Aida Khattab
- Medical Pharmacology Department, Faculty of Medicine, Cairo University, Eqypt
| | | | - Mahmoud M Kamel
- Clinical Pathology Department, National Cancer Institute, Cairo University, Egypt
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10
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Xue B, Kasparek MS, Müller MH, Kreis ME. Modulation of intestinal afferent nerve sensitivity to inflammatory mediators following systemic endotoxin in mice. Neurogastroenterol Motil 2015; 27:550-8. [PMID: 25817056 DOI: 10.1111/nmo.12531] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Accepted: 01/23/2015] [Indexed: 02/08/2023]
Abstract
BACKGROUND Endotoxin exposure may be followed by visceral hypersensitvity but potential mechanisms are not fully explored. We aimed to test the hypothesis that mast cells and the cyclooxygenase pathway (COX) mediate modulation of afferent nerve sensitivity following systemic endotoxin. METHODS C57Bl6 mice received endotoxin injection i.p. to induce systemic inflammation. Control animals received normal saline. Extracellular multi-unit afferent nerve discharge was recorded from jejunal mesenteric nerves in vitro. Afferent nerve response to 5-hydroxytryptamine (5-HT, 250 μmol/L), bradykinin (BK, 0.5 μmol/L), and to mechanical ramp distension of the intestinal lumen from 0 to 60 cmH2O were recorded 2 h following endotoxin administration. KEY RESULTS Following endotoxin administration peak afferent discharge to 5-HT and BK was increased compared to controls (p < 0.05). Pre-perfusion with the mast cell stabilizer Doxantrazole (10(-4) M), or the cyclooxygenase inhibitor Naproxen inhibited the increased response to 5-HT and BK (p < 0.05 vs endotoxin pretreatment). Mechanosensitivity during luminal ramp distension from 10 to 60 cmH2O was increased following endotoxin pretreatment compared to controls (p < 0.05). This increase in sensitivity following endotoxin was no longer observed after Doxantrazole or Naproxen administration for pressures from 10 to 30 cmH2O (p < 0.05). Selective COX-2 inhibition by NS398 (10 μM) but not COX-1 inhibition by SC560 (300 μM) reduced increased afferent discharge in endotoxin pretreated animals to 5-HT, BK and mechanical ramp distension from 10 to 40 cmH2O (all p < 0.05). CONCLUSIONS & INFERENCES Systemic endotoxin sensitizes mesenteric afferent nerve fibers to 5-HT, BK and mechanical stimuli. The underlying mechanism responsible for this sensitization seems to involve mast cells and the COX-2 pathway.
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Affiliation(s)
- B Xue
- Department of Pathophysiology, Medical School, Shandong University, Jinan, China; Department of Surgery, Ludwig-Maximilians University, Munich, Germany
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Li J, Xue B, Han T, Huang K, Gong L, Ma X, Liu K, Cui S, Zhang M, Kunze W, Liu C. Oxytocin down-regulates mesenteric afferent sensitivity via the enteric OTR/nNOS/NO/KATP pathway in rat. Neurogastroenterol Motil 2015; 27:51-62. [PMID: 25346204 DOI: 10.1111/nmo.12469] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 10/08/2014] [Indexed: 12/21/2022]
Abstract
BACKGROUND Oxytocin plays an analgesic role in modulation of nociception and pain. Most work to date has focused on the central mechanisms of oxytocin analgesia, but little is known about whether peripheral mechanisms are also involved. METHODS The mesenteric afferent discharge was recorded in vitro. The expressions of oxytocin receptor (OTR) and neuronal nitric oxide synthase (nNOS) in longitudinal muscle myenteric plexus (LMMP) was identified by immunofluorescence. KEY RESULTS Oxytocin per se had no effect on the jejunal mesenteric afferent discharge, however, it markedly attenuated the bradykinin- or distention-evoked increase of mesenteric afferent discharge, which was mimiced by the nitric oxide (NO) donor sodium nitroprusside (SNP). Pretreatment of either NOS inhibitor L-NAME or NPLA largely reduced the inhibitory effect of oxytocin on bradykinin-evoked mesenteric afferent discharge. Such effect, to a large extent, was also alleviated by N-and P-type voltage-dependent calcium channel antagonists or KATP blocker glibenclamide. In addition, immunofluorescence studies show strong colocalization of OTR with nNOS in LMMP of the rat jejunum. CONCLUSIONS & INFERENCES Oxytocin down-regulates the mesenteric afferent sensitivity through nNOS-NO-KATP pathway. Our findings may reveal a new peripheral mechanism for oxytocin analgesia.
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Affiliation(s)
- J Li
- Department of Physiology, Shandong Provincial Key Laboratory of Mental Disorders, Shandong University School of Medicine, Jinan, China
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Petho G, Reeh PW. Sensory and signaling mechanisms of bradykinin, eicosanoids, platelet-activating factor, and nitric oxide in peripheral nociceptors. Physiol Rev 2013; 92:1699-775. [PMID: 23073630 DOI: 10.1152/physrev.00048.2010] [Citation(s) in RCA: 191] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Peripheral mediators can contribute to the development and maintenance of inflammatory and neuropathic pain and its concomitants (hyperalgesia and allodynia) via two mechanisms. Activation or excitation by these substances of nociceptive nerve endings or fibers implicates generation of action potentials which then travel to the central nervous system and may induce pain sensation. Sensitization of nociceptors refers to their increased responsiveness to either thermal, mechanical, or chemical stimuli that may be translated to corresponding hyperalgesias. This review aims to give an account of the excitatory and sensitizing actions of inflammatory mediators including bradykinin, prostaglandins, thromboxanes, leukotrienes, platelet-activating factor, and nitric oxide on nociceptive primary afferent neurons. Manifestations, receptor molecules, and intracellular signaling mechanisms of the effects of these mediators are discussed in detail. With regard to signaling, most data reported have been obtained from transfected nonneuronal cells and somata of cultured sensory neurons as these structures are more accessible to direct study of sensory and signal transduction. The peripheral processes of sensory neurons, where painful stimuli actually affect the nociceptors in vivo, show marked differences with respect to biophysics, ultrastructure, and equipment with receptors and ion channels compared with cellular models. Therefore, an effort was made to highlight signaling mechanisms for which supporting data from molecular, cellular, and behavioral models are consistent with findings that reflect properties of peripheral nociceptive nerve endings. Identified molecular elements of these signaling pathways may serve as validated targets for development of novel types of analgesic drugs.
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Affiliation(s)
- Gábor Petho
- Pharmacodynamics Unit, Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Pécs, Pécs, Hungary
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Holmes GM. Upper gastrointestinal dysmotility after spinal cord injury: is diminished vagal sensory processing one culprit? Front Physiol 2012; 3:277. [PMID: 22934031 PMCID: PMC3429051 DOI: 10.3389/fphys.2012.00277] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 06/27/2012] [Indexed: 12/12/2022] Open
Abstract
Despite the widely recognized prevalence of gastric, colonic, and anorectal dysfunction after spinal cord injury (SCI), significant knowledge gaps persist regarding the mechanisms leading to post-SCI gastrointestinal (GI) impairments. Briefly, the regulation of GI function is governed by a mix of parasympathetic, sympathetic, and enteric neurocircuitry. Unlike the intestines, the stomach is dominated by parasympathetic (vagal) control whereby gastric sensory information is transmitted via the afferent vagus nerve to neurons of the nucleus tractus solitarius (NTS). The NTS integrates this sensory information with signals from throughout the central nervous system. Glutamatergic and GABAergic NTS neurons project to other nuclei, including the preganglionic parasympathetic neurons of the dorsal motor nucleus of the vagus (DMV). Finally, axons from the DMV project to gastric myenteric neurons, again, through the efferent vagus nerve. SCI interrupts descending input to the lumbosacral spinal cord neurons that modulate colonic motility and evacuation reflexes. In contrast, vagal neurocircuitry remains anatomically intact after injury. This review presents evidence that unlike the post-SCI loss of supraspinal control which leads to colonic and anorectal dysfunction, gastric dysmotility occurs as an indirect or secondary pathology following SCI. Specifically, emerging data points toward diminished sensitivity of vagal afferents to GI neuroactive peptides, neurotransmitters and, possibly, macronutrients. The neurophysiological properties of rat vagal afferent neurons are highly plastic and can be altered by injury or energy balance. A reduction of vagal afferent signaling to NTS neurons may ultimately bias NTS output toward unregulated GABAergic transmission onto gastric-projecting DMV neurons. The resulting gastroinhibitory signal may be one mechanism leading to upper GI dysmotility following SCI.
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Affiliation(s)
- Gregory M. Holmes
- Neural and Behavioral Sciences, Penn State University College of MedicineHershey, PA, USA
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Tong M, Qualls-Creekmore E, Browning KN, Travagli RA, Holmes GM. Experimental spinal cord injury in rats diminishes vagally-mediated gastric responses to cholecystokinin-8s. Neurogastroenterol Motil 2011; 23:e69-79. [PMID: 20950355 PMCID: PMC3021002 DOI: 10.1111/j.1365-2982.2010.01616.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND We have shown recently that our model of experimental high-thoracic spinal cord injury (T3-SCI) mirrors the gastrointestinal clinical presentation of neurotrauma patients, whereby T3-SCI animals show diminished gastric emptying and dysmotility. In this study we used cholecystokinin as a model peptide to test the hypothesis that the T3-SCI induced gastroparesis is due, in part, to an impaired vagally-mediated response to gastrointestinal peptides. METHODS We measured the responses to sulfated cholecystokinin (CCK-8s) in control and T3-SCI (3 or 21 days after injury) rats utilizing: (i) c-fos expression in the nucleus tractus solitarius (NTS) following peripherally administered CCK-8s; (ii) in vivo gastric tone and motility following unilateral microinjection of CCK-8s into the dorsal vagal complex (DVC); and (iii) whole cell recordings of glutamatergic synaptic inputs to NTS neurons. KEY RESULTS Our results show that: (i) medullary c-fos expression in response to peripheral CCK-8s was significantly lower in T3-SCI rats 3 days after the injury, but recovered to control values at 3 weeks post-SCI, (ii) Unilateral microinjection of CCK-8s in the DVC induced a profound gastric relaxation in control animals, but did not induce any response in T3-SCI rats at both 3 and 21 days after SCI, (iii) Perfusion with CCK-8s increased glutamatergic currents in 55% of NTS neurons from control rats, but failed to induce any response in NTS neurons from T3-SCI rats. CONCLUSIONS & INFERENCES Our data indicate alterations of vagal responses to CCK-8s in T3-SCI rats that may reflect a generalized impairment of gastric vagal neurocircuitry, leading to a reduction of gastric functions after SCI.
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Affiliation(s)
| | | | - Kirsteen N. Browning
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, Hershey, PA 17033
| | - R. Alberto Travagli
- Department of Neural and Behavioral Sciences, Penn State University College of Medicine, Hershey, PA 17033
| | - Gregory M. Holmes
- Corresponding Author: Dr. Gregory M. Holmes, Pennington Biomedical Research Center, 6400 Perkins Rd., Baton Rouge, LA 70808, Tel: +1 225 763 2520, fax; +1 225 763 2525,
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