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Chang WY, Yang YT, She MP, Tu CH, Lee TC, Wu MS, Sun CH, Hsin LW, Yu LCH. 5-HT 7 receptor-dependent intestinal neurite outgrowth contributes to visceral hypersensitivity in irritable bowel syndrome. J Transl Med 2022; 102:1023-1037. [PMID: 36775417 PMCID: PMC9420680 DOI: 10.1038/s41374-022-00800-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 04/22/2022] [Accepted: 04/22/2022] [Indexed: 12/19/2022] Open
Abstract
Irritable bowel syndrome (IBS) is characterized by visceral hypersensitivity (VH) associated with abnormal serotonin/5-hydroxytryptamine (5-HT) metabolism and neurotrophin-dependent mucosal neurite outgrowth. The underlying mechanisms of VH remain poorly understood. We investigated the role of 5-HT7 receptor in mucosal innervation and intestinal hyperalgesia. A high density of mucosal nerve fibres stained for 5-HT7 was observed in colonoscopic biopsy specimens from IBS patients compared with those from healthy controls. Staining of 5-HT3 and 5-HT4 receptors was observed mainly in colonic epithelia with comparable levels between IBS and controls. Visceromotor responses to colorectal distension were evaluated in two mouse models, one postinfectious with Giardia and subjected to water avoidance stress (GW) and the other postinflammatory with trinitrobenzene sulfonic acid-induced colitis (PT). Increased VH was associated with higher mucosal density of 5-HT7-expressing nerve fibres and elevated neurotrophin and neurotrophin receptor levels in the GW and PT mice. The increased VH was inhibited by intraperitoneal injection of SB-269970 (a selective 5-HT7 antagonist). Peroral multiple doses of CYY1005 (a novel 5-HT7 ligand) decreased VH and reduced mucosal density of 5-HT7-expressing nerve fibres in mouse colon. Human neuroblastoma SH-SY5Y cells incubated with bacteria-free mouse colonic supernatant, 5-HT, nerve growth factor, or brain-derived neurotrophic factor exhibited nerve fibre elongation, which was inhibited by 5-HT7 antagonists. Gene silencing of HTR7 also reduced the nerve fibre length. Activation of 5-HT7 upregulated NGF and BDNF gene expression, while stimulation with neurotrophins increased the levels of tryptophan hydroxylase 2 and 5-HT7 in neurons. A positive-feedback loop was observed between serotonin and neurotrophin pathways via 5-HT7 activation to aggravate fibre elongation, whereby 5-HT3 and 5-HT4 had no roles. In conclusion, 5-HT7-dependent mucosal neurite outgrowth contributed to VH. A novel 5-HT7 antagonist could be used as peroral analgesics for IBS-related pain.
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Affiliation(s)
- Wen-Ying Chang
- Graduate Institute of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan ROC
| | - Yi-Ting Yang
- Graduate Institute of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan ROC
| | - Meng-Ping She
- Graduate Institute of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan ROC
| | - Chia-Hung Tu
- Department of Internal Medicine, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan ROC
| | - Tsung-Chun Lee
- Department of Internal Medicine, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan ROC
| | - Ming-Shiang Wu
- Department of Internal Medicine, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan ROC
| | - Chin-Hung Sun
- Department of Tropical Medicine and Parasitology, National Taiwan University College of Medicine, Taipei, Taiwan ROC
| | - Ling-Wei Hsin
- Graduate Institute of Pharmacy, National Taiwan University School of Pharmacy, Taipei, Taiwan ROC.
- Center for Innovative Therapeutics Discovery, National Taiwan University, Taipei, Taiwan ROC.
| | - Linda Chia-Hui Yu
- Graduate Institute of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan ROC.
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Takahashi K, Khwaja IG, Schreyer JR, Bulmer D, Peiris M, Terai S, Aziz Q. Post-inflammatory Abdominal Pain in Patients with Inflammatory Bowel Disease During Remission: A Comprehensive Review. CROHN'S & COLITIS 360 2021; 3:otab073. [PMID: 36777266 PMCID: PMC9802269 DOI: 10.1093/crocol/otab073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Indexed: 11/13/2022] Open
Abstract
Patients with inflammatory bowel disease often experience ongoing pain even after achieving mucosal healing (i.e., post-inflammatory pain). Factors related to the brain-gut axis, such as peripheral and central sensitization, altered sympatho-vagal balance, hypothalamic-pituitary-adrenal axis activation, and psychosocial factors, play a significant role in the development of post-inflammatory pain. A comprehensive study investigating the interaction between multiple predisposing factors, including clinical psycho-physiological phenotypes, molecular mechanisms, and multi-omics data, is still needed to fully understand the complex mechanism of post-inflammatory pain. Furthermore, current treatment options are limited and new treatments consistent with the underlying pathophysiology are needed to improve clinical outcomes.
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Affiliation(s)
- Kazuya Takahashi
- Centre for Neuroscience, Surgery and Trauma, Wingate Institute of Neurogastroenterology, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.,Division of Gastroenterology and Hepatology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Iman Geelani Khwaja
- Centre for Neuroscience, Surgery and Trauma, Wingate Institute of Neurogastroenterology, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Jocelyn Rachel Schreyer
- Centre for Neuroscience, Surgery and Trauma, Wingate Institute of Neurogastroenterology, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - David Bulmer
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Madusha Peiris
- Centre for Neuroscience, Surgery and Trauma, Wingate Institute of Neurogastroenterology, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Shuji Terai
- Division of Gastroenterology and Hepatology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Qasim Aziz
- Centre for Neuroscience, Surgery and Trauma, Wingate Institute of Neurogastroenterology, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
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Wang C, Fang X. Inflammation and Overlap of Irritable Bowel Syndrome and Functional Dyspepsia. J Neurogastroenterol Motil 2021; 27:153-164. [PMID: 33795538 PMCID: PMC8026374 DOI: 10.5056/jnm20175] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 11/23/2020] [Accepted: 11/29/2020] [Indexed: 12/13/2022] Open
Abstract
Irritable bowel syndrome (IBS) and functional dyspepsia (FD) are common functional gastrointestinal disorders (FGIDs) and account for a large proportion of consulting patients. These 2 disorders overlap with each other frequently. The pathogenesis of IBS or FD is complicated and multi-factors related, in which infectious or non-infectious inflammation and local or systemic immune response play significant roles. There are few studies focusing on the mechanism of inflammation in patients with overlap syndrome of irritable bowel syndrome and functional dyspepsia (IBS-FD). This review focuses on current advances about the role of inflammation in the pathogenesis of IBS and FD and the possible mechanism of inflammation in IBS-FD.
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Affiliation(s)
- Congzhen Wang
- Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xiucai Fang
- Department of Gastroenterology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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Salaga M, Binienda A, Piscitelli F, Mokrowiecka A, Cygankiewicz AI, Verde R, Malecka-Panas E, Kordek R, Krajewska WM, Di Marzo V, Fichna J. Systemic administration of serotonin exacerbates abdominal pain and colitis via interaction with the endocannabinoid system. Biochem Pharmacol 2019; 161:37-51. [DOI: 10.1016/j.bcp.2019.01.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 01/02/2019] [Indexed: 12/24/2022]
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Abstract
The gastrointestinal (GI) system is responsible for the digestion and absorption of ingested food and liquids. Due to the complexity of the GI tract and the substantial volume of material that could be covered under the scope of GI physiology, this chapter briefly reviews the overall function of the GI tract, and discusses the major factors affecting GI physiology and function, including the intestinal microbiota, chronic stress, inflammation, and aging with a focus on the neural regulation of the GI tract and an emphasis on basic brain-gut interactions that serve to modulate the GI tract. GI diseases refer to diseases of the esophagus, stomach, small intestine, colon, and rectum. The major symptoms of common GI disorders include recurrent abdominal pain and bloating, heartburn, indigestion/dyspepsia, nausea and vomiting, diarrhea, and constipation. GI disorders rank among the most prevalent disorders, with the most common including esophageal and swallowing disorders, gastric and peptic ulcer disease, gastroparesis or delayed gastric emptying, irritable bowel syndrome (IBS), and inflammatory bowel disease (IBD). Many GI disorders are difficult to diagnose and their symptoms are not effectively managed. Thus, basic research is required to drive the development of novel therapeutics which are urgently needed. One approach is to enhance our understanding of gut physiology and pathophysiology especially as it relates to gut-brain communications since they have clinical relevance to a number of GI complaints and represent a therapeutic target for the treatment of conditions including inflammatory diseases of the GI tract such as IBD and functional gut disorders such as IBS.
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Mueller MH, Zhao X, Macheroux T, Kasparek MS, Seeliger H, Kreis ME. Differential activation of afferent neuronal and inflammatory pathways during small bowel obstruction (SBO). Neurogastroenterol Motil 2016; 28:1599-608. [PMID: 27271363 DOI: 10.1111/nmo.12861] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Accepted: 04/22/2016] [Indexed: 01/01/2023]
Abstract
BACKGROUND Small bowel obstruction (SBO) is a potentially life-threatening condition which may be caused by a variety of pathologies such as postoperative adhesions or malignant diseases. Little is known on alterations in gut physiology during SBO, although its comprehension is essential to improve treatment which may help to prevent subsequent organ failure prior to surgical resolution. We aimed to investigate afferent nerve sensitivity and intestinal inflammatory response during SBO to identify possible targets of treatment. METHODS C57Bl6 mice were anesthetized, and a midline laparotomy was performed. A small bowel loop was ligated 5 cm proximal to ileo-cecal valve to induce SBO. Control animals received a sham midline laparotomy. SBO animals and controls were sacrificed after 3, 9, or 24 h (each n = 6). A dilated segment of small intestine located 1.5 cm oral to the ligature was prepared for multi-unit mesenteric afferent nerve recordings in vitro. Histological assessment of leukocyte infiltration was performed by myeloperoxidase (MPO). Pro-inflammatory cytokine expression was quantified by RT-PCR. Data are mean ± SEM. KEY RESULTS Afferent firing to serosal 5-HT (500 μM) peaked at 3.9 ± 0.2 impulse/s 24 h after induction of SBO compared to 2.4 ± 0.1 impulse/s in sham controls (p < 0.05). Serosal bradykinin (0.5 μM) led to an increase in peak afferent firing of 5.3 ± 0.5 impulse/s in 24 h SBO animals compared to 3.5 ± 0.2 impulse/s in sham controls (p < 0.05). No differences in 5-HT and BK sensitivity were observed in 3 and 9 h SBO animals compared to controls. Continuous mechanical ramp distension of the intestinal loop was followed by a pressure-dependent rise in afferent nerve discharge that was reduced in 3 h SBO animals compared to sham controls (p < 0.05). MPO stains showed a rise in leukocyte infiltration of the intestine in SBO animals at 9 and 24 h (p < 0.05). Il-6 but not TNF-a gene expression was increased at 9 and 24 h in SBO animals compared to sham controls (p < 0.05). CONCLUSIONS & INFERENCES Afferent nerve sensitivity is increased 24 h after induction of SBO. SBO led to a delayed onset intestinal inflammatory response. Inflammatory mediators released during this inflammatory response may be responsible for a later increase in afferent sensitivity. Agents with anti-inflammatory action may, therefore, have a beneficial effect during SBO and may subsequently help to prevent possible organ dysfunction.
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Affiliation(s)
- M H Mueller
- Department of Surgery, Campus Benjamin Franklin, Charité University Medicine, Berlin, Germany.
| | - X Zhao
- Department of Gastroenterology, Ludwig-Maximilian's University, Munich, Germany
| | - T Macheroux
- Department of Surgery, Ludwig-Maximilian's University, Munich, Germany
| | - M S Kasparek
- Department of Surgery, Josephinum Hospital, Munich, Germany
| | - H Seeliger
- Department of Surgery, Campus Benjamin Franklin, Charité University Medicine, Berlin, Germany
| | - M E Kreis
- Department of Surgery, Campus Benjamin Franklin, Charité University Medicine, Berlin, Germany
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Li H, Hu S, Zhang J, Zhou J, Ran H, Tang Y, Chen J, Wang Y. Effects and mechanisms of auricular electroacupuncture on visceral pain induced by colorectal distension in conscious rats. Acupunct Med 2014; 32:472-7. [PMID: 25193927 DOI: 10.1136/acupmed-2014-010575] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE To investigate the effects and mechanisms of action of auricular electroacupuncture (AEA) on visceral pain induced by colorectal distension (CRD). METHODS Twenty-nine female Sprague-Dawley rats were randomly divided into four groups: control; untreated CRD; CRD+AEA; and CRD+sham electroacupuncture (SEA). An electromyogram (EMG) was recorded for 120 min in the conscious state. After a 30 min baseline recording, CRD was performed in untreated CRD, AEA and SEA groups and lasted for 90 min. AEA and SEA were started at 30 min and lasted for 30 min. The EMG was recorded and analysed to evaluate the severity of visceral pain, indicated by the magnitude of the vasomotor response (VMR). mRNA expression of the 5-hydroxytryptamine 1a (5-HT1a) receptor was measured separately in the colon and raphe nuclei using real-time fluorescent quantitative PCR. RESULTS No differences were seen in the baseline EMG among the four groups (p>0.05). During pre-stimulation, VMR magnitude in the CRD, AEA and SEA groups increased compared with that in the control group (p<0.05). During stimulation, the VMR magnitude was significantly decreased in AEA but not SEA groups relative to the (untreated) CRD group. Similarly, mRNA expression of the 5-HT1a receptor in both the colon and raphe nuclei was lower in AEA but not SEA groups compared with the CRD group (p<0.05). CONCLUSIONS AEA can ameliorate CRD-induced visceral pain in rats, and increase mRNA expression of the 5-HT1a receptor peripherally (in the colon) and centrally (in the raphe nuclei), suggesting a serotonergic mechanism of action.
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Affiliation(s)
- Han Li
- Department of Acupuncture and Moxibustion, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Shasha Hu
- Department of Acupuncture and Moxibustion, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Jianbin Zhang
- Department of Acuology, The Second Clinical College, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China
| | - Jingzhu Zhou
- Department of Acupuncture and Moxibustion, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Hongxing Ran
- Department of Acupuncture and Moxibustion, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Yichun Tang
- Department of Acuology, The Second Clinical College, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, China
| | - Jiande Chen
- Division of Gastroenterology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Yinping Wang
- Department of Acupuncture and Moxibustion, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
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Feng CC, Yan XJ, Chen X, Wang EM, Liu Q, Zhang LY, Chen J, Fang JY, Chen SL. Vagal anandamide signaling via cannabinoid receptor 1 contributes to luminal 5-HT modulation of visceral nociception in rats. Pain 2014; 155:1591-1604. [PMID: 24813296 DOI: 10.1016/j.pain.2014.05.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 04/24/2014] [Accepted: 05/02/2014] [Indexed: 12/19/2022]
Abstract
Serotonin (5-HT) plays pivotal roles in the pathogenesis of postinfectious irritable bowel syndrome (PI-IBS), and luminal 5-HT time-dependently modulates visceral nociception. We found that duodenal biopsies from PI-IBS patients exhibited increased 5-HT and decreased anandamide levels and that decreased anandamide was associated with abdominal pain severity, indicating a link between 5-HT and endocannabinoid signaling pathways in PI-IBS. To understand this, we investigated the role of endocannabinoids in 5-HT modulation of visceral nociception in a rat model. Acute intraduodenally applied 5-HT attenuated the visceromotor response (VMR) to colorectal distention, and this was reversed by the cannabinoid receptor 1 (CB1) antagonist AM251. Duodenal anandamide (but not 2-arachidonoylglycerol) content was greatly increased after luminal 5-HT treatment. This effect was abrogated by the 5-HT 3 receptor (5-HT3R) antagonist granisetron, which was luminally delivered to preferentially target vagal terminals. Chemical denervation of vagal afferents blocked 5-HT-evoked antinociception and anandamide release. Chronic luminal 5-HT exposure for 5 days increased baseline VMR and VMR post-5-HT (days 4 and 5). Duodenal levels of anandamide and N-acyl-phosphatidylethanolamine-specific phospholipase D (NAPE-PLD, the anandamide-synthesizing enzyme) protein gradually declined from day 1 to 5. The time-dependent effects of 5-HT were abolished by daily granisetron pretreatment. Daily pretreatment with CB1 agonists or anandamide from day 3 attenuated 5-HT-induced hyperalgesia. These data suggest that vagal 5-HT3R-mediated duodenal anandamide release contributes to acute luminal 5-HT-induced antinociception via CB1 signaling, whereas decreased anandamide is associated with hyperalgesia upon chronic 5-HT treatment. Further understanding of peripheral vagal anandamide signaling may provide insights into the mechanisms underlying 5-HT-related IBS.
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Affiliation(s)
- Chen-Chen Feng
- Department of Gastroenterology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai Institute of Digestive Disease, 145 Middle Shandong Road, Shanghai, China Department of pharmaceutics, Key Laboratory of Smart Drug Delivery, Ministry of Education & PLA, School of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai, China
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Yan XJ, Feng CC, Liu Q, Zhang LY, Dong X, Liu ZL, Cao ZJ, Mo JZ, Li Y, Fang JY, Chen SL. Vagal Afferents Mediate Antinociception of Estrogen in a Rat Model of Visceral Pain: The Involvement of Intestinal Mucosal Mast Cells and 5-Hydroxytryptamine 3 Signaling. THE JOURNAL OF PAIN 2014; 15:204-17. [DOI: 10.1016/j.jpain.2013.10.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Revised: 09/14/2013] [Accepted: 10/31/2013] [Indexed: 12/19/2022]
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Kim ER, Min BH, Lee TH, Son M, Rhee PL. Effect of DA-9701 on colorectal distension-induced visceral hypersensitivity in a rat model. Gut Liver 2014; 8:388-93. [PMID: 25071903 PMCID: PMC4113047 DOI: 10.5009/gnl.2014.8.4.388] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2013] [Revised: 05/22/2013] [Accepted: 07/07/2013] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND/AIMS DA-9701 is a newly developed drug made from the vegetal extracts of Pharbitidis semen and Co-rydalis tuber. The aim of this study was to evaluate the effect of DA-9701 on colorectal distension (CRD)-induced visceral hypersensitivity in a rat model. METHODS Male Sprague-Dawley rats were subjected to neonatal colon irritation (CI) using CRD at 1 week after birth (CI group). At 6 weeks after birth, CRD was applied to these rats with a pressure of 20 to 90 mm Hg, and changes in the mean arterial pressure (MAP) were measured at baseline (i.e., without any drug administration) and after the administration of different doses of DA-9701. RESULTS In the absence of DA-9701, the MAP changes after CRD were significantly higher in the CI group than in the control group at all applied pressures. In the control group, MAP changes after CRD were not significantly affected by the administration of DA-9701. In the CI group, however, the administration of DA-9701 resulted in a significant decrease in MAP changes after CRD. The administration of DA-9701 at a dose of 1.0 mg/kg produced a more significant decrease in MAP changes than the 0.3 mg/kg dose. CONCLUSIONS The administration of DA-9701 resulted in a significant increase in pain threshold in rats with CRD-induced visceral hypersensitivity.
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Affiliation(s)
- Eun Ran Kim
- Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Byung-Hoon Min
- Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Tae Ho Lee
- Dong-A ST, Co., Ltd., Research Center, Yongin, Korea
| | - Miwon Son
- Dong-A ST, Co., Ltd., Research Center, Yongin, Korea
| | - Poong-Lyul Rhee
- Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
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Current World Literature. Curr Opin Support Palliat Care 2012; 6:109-25. [DOI: 10.1097/spc.0b013e328350f70c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Furuta S, Watanabe L, Doi S, Horiuchi H, Matsumoto K, Kuzumaki N, Suzuki T, Narita M. Subdiaphragmatic vagotomy increases the sensitivity of lumbar Aδ primary afferent neurons along with voltage-dependent potassium channels in rats. Synapse 2011; 66:95-105. [PMID: 21905127 DOI: 10.1002/syn.20982] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 08/21/2011] [Accepted: 08/25/2011] [Indexed: 11/07/2022]
Abstract
Subdiaphragmatic vagal dysfunction causes chronic pain. To verify whether this chronic pain is accompanied by enhanced peripheral nociceptive sensitivity, we evaluated primary afferent neuronal excitability in subdiaphragmatic vagotomized (SDV) rats. SDV rats showed a decrease in the electrical stimuli-induced hind limb-flexion threshold at 250 Hz, but showed no similar effect at 5 or 2000 Hz, which indicated that lumbar primary afferent Aδ sensitivity was enhanced in SDV rats. The whole-cell patch-clamp technique also revealed the hyper-excitability of acutely dissociated medium-sized lumbar dorsal root ganglion (DRG) neurons isolated from SDV rats. The contribution of changes in voltage-dependent potassium (Kv) channels was assessed, and transient A-type K(+) (I(A) ) current density was apparently decreased. Moreover, Kv4.3 immunoreactivity in medium-sized DRG neurons was significantly reduced in SDV rats compared to sham. These results indicate that SDV causes hyper-excitability of lumbar primary Aδ afferent neurons, which may be induced along with suppressing I(A) currents via the decreased expression of Kv4.3. Thus, peripheral Aδ neuroplasticity may contribute to the chronic lower limb pain caused by SDV.
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Affiliation(s)
- Sadayoshi Furuta
- Department of Toxicology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan
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Furuta S, Matsumoto K, Horie S, Suzuki T, Narita M. Subdiaphragmatic vagotomy induces a functional change in visceral Aδ primary afferent fibers in rats. Synapse 2011; 66:369-71. [DOI: 10.1002/syn.20991] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2011] [Accepted: 09/14/2011] [Indexed: 11/07/2022]
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