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Zhang S, Li S, Liu Y, Ye F, Yin J, Foreman RD, Wang D, Chen JDZ. Electroacupuncture via chronically implanted electrodes improves gastric dysmotility mediated by autonomic-cholinergic mechanisms in a rodent model of functional dyspepsia. Neurogastroenterol Motil 2018; 30:e13381. [PMID: 29856090 DOI: 10.1111/nmo.13381] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 04/20/2018] [Indexed: 12/14/2022]
Abstract
BACKGROUND Electroacupuncture (EA) has been shown to be effective in reducing symptoms in patients with functional dyspepsia (FD). However, its mechanisms remain largely unknown. The aim of this study was to investigate mechanisms of the prokinetic effects of EA in a rodent model of FD. METHODS A FD model was established by neonatal treatment of iodoacetamide (IA). Eight weeks later, the rats were implanted with electrodes in the stomach for the measurement of gastric slow waves (GSW) and electrodes into acupoints ST36 for EA. Autonomic functions were assessed by the spectral analysis of heart rate variability. KEY RESULTS (i) The IA-treated rats ("FD" rats) showed increased dysrhythmia in both fasting and fed states (P < .01) as well as during rectal distention (P < .02). EA reduced the percentage of dysrhythmia (P < .05 for both fasting and fed) and normalized RD-induced impairment in GSW in "FD" rats. Atropine blocked the effect of EA on GSW. (ii) "FD" rats showed delayed gastric emptying (P = .001 vs control) that was accelerated with EA (P = .01, vs sham-EA). (iii) "FD" rats showed increased plasma norepinephrine (P = .006, vs control) that was suppressed with EA (P = .003) and reduced vagal activity that was improved with EA. CONCLUSIONS AND INFERENCES Gastric motility (GSW and GE) is impaired in rats treated with IA, possibly attributed to impaired autonomic functions. EA improves GSW and accelerates GE mediated via the autonomic and cholinergic mechanisms.
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Affiliation(s)
- S Zhang
- Veterans Research and Education Foundation, VA Medical Center, Oklahoma City, OK, USA.,Department of Physiology, University of Oklahoma Health Science Center, Oklahoma City, OK, USA.,Department of Gastroenterology, Tianjin No. 254 Hospital, Tianjin, China
| | - S Li
- Veterans Research and Education Foundation, VA Medical Center, Oklahoma City, OK, USA.,Division of Gastroenterology and Hepatology, Johns Hopkins Center for Neurogastroenterology, Baltimore, MD, USA
| | - Y Liu
- Veterans Research and Education Foundation, VA Medical Center, Oklahoma City, OK, USA.,Department of Physiology, University of Oklahoma Health Science Center, Oklahoma City, OK, USA.,Department of traditional Chinese medicine, 1st Affiliated Hospital of Xi'an Jiao tong University, Xi'an, Shannxi, China
| | - F Ye
- Veterans Research and Education Foundation, VA Medical Center, Oklahoma City, OK, USA.,Department of Physiology, University of Oklahoma Health Science Center, Oklahoma City, OK, USA.,Department of Hepatology, 1st Affiliated Hospital of Xi'an Jiao Tong University, Xi'an, Shannxi, China
| | - J Yin
- Veterans Research and Education Foundation, VA Medical Center, Oklahoma City, OK, USA.,Division of Gastroenterology and Hepatology, Johns Hopkins Center for Neurogastroenterology, Baltimore, MD, USA
| | - R D Foreman
- Department of Physiology, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - D Wang
- Department of Gastroenterology, Tianjin No. 254 Hospital, Tianjin, China
| | - J D Z Chen
- Veterans Research and Education Foundation, VA Medical Center, Oklahoma City, OK, USA.,Division of Gastroenterology and Hepatology, Johns Hopkins Center for Neurogastroenterology, Baltimore, MD, USA
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Song J, Yin J, Chen JDZ. Inhibitory Effects and Sympathetic Mechanisms of Distension in the Distal Organs on Small Bowel Motility and Slow Waves in Canine. Cell Biochem Biophys 2017; 73:665-72. [PMID: 27259308 DOI: 10.1007/s12013-015-0679-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Rectal distension (RD) is known to induce intestinal dysmotility. Few studies were performed to compare effects of RD, colon distension (CD) and duodenal distension (DD) on small bowel motility. This study aimed to investigate effects and underlying mechanisms of distensions in these regions on intestinal motility and slow waves. Eight dogs chronically implanted with a duodenal fistula, a proximal colon fistula, and intestinal serosal electrodes were studied in six sessions: control, RD, CD, DD, RD + guanethidine, and CD + guanethidine. Postprandial intestinal contractions and slow waves were recorded for the assessment of intestinal motility. The electrocardiogram was recorded for the assessment of autonomic functions. (1) Isobaric RD and CD suppressed intestinal contractions (contractile index: 6.0 ± 0.4 with RD vs. 9.9 ± 0.9 at baseline, P = 0.001, 5.3 ± 0.2 with CD vs. 7.7 ± 0.8 at baseline, P = 0.008). Guanethidine at 3 mg/kg iv was able to partially block the effects. (2) RD and CD reduced the percentage of normal intestinal slow waves from 92.1 ± 2.8 to 64.2 ± 3.4 % (P < 0.001) and from 90 ± 2.7 to 69.2 ± 3.7 % (P = 0.01), respectively. Guanethidine could eliminate these inhibitory effects. (3) DD did not induce any changes in small intestinal contractions and slow waves (P > 0.05). (4) The spectral analysis of the heart rate variability showed that both RD and CD increased sympathetic activity (LF) and reduced vagal activity (HF) (P < 0.05). Isobaric RD and CD could inhibit postprandial intestinal motility and impair intestinal slow waves, which were mediated via the sympathetic pathway. However, DD at a site proximal to the measurement site did not seem to impair small intestinal contractions or slow waves.
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Affiliation(s)
- Jun Song
- Division of Gastroenterology, University of Texas Medical Branch, Galveston, TX, USA.,Department of Gastroenterology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Jieyun Yin
- Division of Gastroenterology, University of Texas Medical Branch, Galveston, TX, USA.,Ningbo Pace Translational Medical Research Center, Beilun, Ningbo, People's Republic of China
| | - Jiande D Z Chen
- Division of Gastroenterology, University of Texas Medical Branch, Galveston, TX, USA. .,Ningbo Pace Translational Medical Research Center, Beilun, Ningbo, People's Republic of China. .,Division of Gastroenterology and Hepatology, Johns Hopkins Center for Neurogastroenterology, Johns Hopkins University, Baltimore, MD, 21224, USA.
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Uchida M, Iwamoto C. Effect of colonic distension on gastric adaptive relaxation in rats: barostatic evaluation using an orally introduced gastric balloon. J Smooth Muscle Res 2016; 50:78-84. [PMID: 26081370 PMCID: PMC5137303 DOI: 10.1540/jsmr.50.78] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
While the gastrocolonic reflex has been known, the cologastric relationship has not been
clarified especially with regard to gastric adaptive relaxation. Therefore, in this study
we have examined the correlation between gastric adaptive relaxation and colonic
distension. Male Sprague-Dawley rats were used after fasting for 18 h. Colonic distension
was performed by injecting 2.2 ml of air into a colonic balloon inserted into the colon
for 5 min in conscious state. After urethane anesthesia, gastric adaptive relaxation was
investigated by using a slightly modified gastric balloon introduced into the stomach
through the mouth. Gastric balloon volumes increased gradually just after an increment in
the gastric balloon pressure (1 to 8 mmHg), and reached a plateau within 1 min. This
increased volume was defined as gastric adaptive relaxation. In control rats, gastric
adaptive relaxation increased with pressure increments in a pressure dependent manner. In
the colon-distended rats, gastric adaptive relaxation increased also in a pressure
dependent manner, but was significantly inhibited as compared with control at 8 mmHg
(P<0.05). These findings show that colonic distension inhibits the
gastric adaptive relaxation and suggests the existence of a cologastric relationship in
rats.
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Affiliation(s)
- Masayuki Uchida
- Food Science Research Laboratories, Division of Research and Development, Meiji Co. Ltd., Japan
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Jin H, Liu J, Foreman RD, Chen JDZ, Yin J. Electrical neuromodulation at acupoint ST36 normalizes impaired colonic motility induced by rectal distension in dogs. Am J Physiol Gastrointest Liver Physiol 2015; 309:G368-76. [PMID: 26113299 DOI: 10.1152/ajpgi.00467.2014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 06/17/2015] [Indexed: 01/31/2023]
Abstract
Electroacupuncture (EA) has been shown to improve impaired gastric motility and slow waves in both humans and animals. However, its effects on colonic motility have rarely been investigated. The aim of this study was to investigate the effects and underlying mechanisms of EA on impaired colonic motility induced by rectal distension (RD)in dogs. Colon contractions and transit were measured in various sessions with and without EA in hound dogs chronically placed with a colonic cannula. Colonic contractile activity was assessed by motility index (MI). Autonomic functions were determined by the spectral analysis of the heart rate variability derived from the electrocardiogram. It was found 1) RD suppressed colonic motility by 40.5% (10.8 ± 0.9 with RD vs. 6.4 ± 0.8 at baseline, P < 0.002). EA at ST36 normalized colonic contractions suppressed by RD (12.9 ± 2.8, P < 0.002 vs. RD and P = 0.1 vs. control). 2) Administration of atropine blocked the ameliorating effect of EA on colon motility. 3) RD also delayed colonic transit (65.0 ± 2.0% with RD vs. 86.0 ± 1.9% without RD, P < 0.001) that was restored with EA (84.0 ± 1.9%, P = 0.178 vs. control). 4) EA increased vagal activity suppressed by RD (0.37 ± 0.07 with RD + EA vs. 0.09 ± 0.03 with RD without EA, P < 0.001). In conclusion, RD inhibits colonic contractions and delays colonic transit in dogs; EA at ST36 restores the RD-induced impairment in both colonic contraction and transit by enhancing vagal activity and mediated via the cholinergic pathway.
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Affiliation(s)
- Haifeng Jin
- Veterans Research and Education Foundation, Veterans Affairs Medical Center, Oklahoma City, Oklahoma; Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma; The First Affiliated Hospital of Zhejiang Chinese Medicine University, Hangzhou, China
| | - Jiemin Liu
- Veterans Research and Education Foundation, Veterans Affairs Medical Center, Oklahoma City, Oklahoma; Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma; Guizhou Provincial People's Hospital, Guizhou, Guiyang, China
| | - Robert D Foreman
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Jiande D Z Chen
- Veterans Research and Education Foundation, Veterans Affairs Medical Center, Oklahoma City, Oklahoma; Ningbo Pace Translational Research Center, Beilun, Ningbo, China; and Division of Gastroenterology and Hepatology, Johns Hopkins Center for Neurogastroenterology, Baltimore, Maryland
| | - Jieyun Yin
- Veterans Research and Education Foundation, Veterans Affairs Medical Center, Oklahoma City, Oklahoma; Division of Gastroenterology and Hepatology, Johns Hopkins Center for Neurogastroenterology, Baltimore, Maryland
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Palheta MS, Graça JRVD, Santos AAD, Lopes LH, Palheta Júnior RC, Nobre E Souza MÂ. The participation of the nitrergic pathway in increased rate of transitory relaxation of lower esophageal sphincter induced by rectal distension in dogs. ARQUIVOS DE GASTROENTEROLOGIA 2015; 51:102-6. [PMID: 25003260 DOI: 10.1590/s0004-28032014000200006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2014] [Accepted: 02/12/2014] [Indexed: 02/03/2023]
Abstract
CONTEXT The rectal distension in dogs increases the rate of transitory lower esophageal sphincter relaxation considered the main factor causing gastroesophageal reflux. OBJECTIVES The aim of this study was evaluate the participation of the nitrergic pathway in the increased transitory lower esophageal sphincter relaxation rate induced by rectal distension in anesthetized dogs. METHODS Male mongrel dogs (n = 21), weighing 10-15 kg, were fasted for 12 hours, with water ad libitum. Thereafter, they were anesthetized (ketamine 10 mg.Kg-1 + xylazine 20 mg.Kg-1), so as to carry out the esophageal motility evaluation protocol during 120 min. After a 30-minute basal period, the animals were randomly intravenous treated whith: saline solution 0.15M (1ml.Kg-1), L-NAME (3 mg.Kg-1), L-NAME (3 mg.Kg-1) + L-Arginine (200 mg.Kg-1), glibenclamide (1 mg.Kg-1) or methylene blue (3 mg.Kg-1). Forty-five min after these pre-treatments, the rectum was distended (rectal distension, 5 mL.Kg-1) or not (control) with a latex balloon, with changes in the esophageal motility recorded over 45 min. Data were analyzed using ANOVA followed by Student Newman-Keuls test. RESULTS In comparison to the respective control group, rectal distension induces an increase in transitory lower esophageal sphincter relaxation. Pre-treatment with L-NAME or methylene blue prevents (P<0.05) this phenomenon, which is reversible by L-Arginine plus L-NAME. However, pretreating with glibenclamide failed to abolish this process. CONCLUSIONS Therefore, these experiments suggested, that rectal distension increases transitory lower esophageal sphincter relaxation in dogs via through nitrergic pathways.
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Affiliation(s)
- Michel Santos Palheta
- Departamento de Cirurgia, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brasil
| | | | - Armênio Aguiar dos Santos
- Departmento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brasil
| | - Liziane Hermógenes Lopes
- Departmento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brasil
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Kwon YS, Son M. DA-9701: A New Multi-Acting Drug for the Treatment of Functional Dyspepsia. Biomol Ther (Seoul) 2013; 21:181-9. [PMID: 24265862 PMCID: PMC3830115 DOI: 10.4062/biomolther.2012.096] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 03/12/2013] [Accepted: 03/14/2013] [Indexed: 12/17/2022] Open
Abstract
Motilitone® (DA-9701) is a new herbal drug that was launched for the treatment of functional dyspepsia in December 2011 in Korea. The heterogeneous symptom pattern and multiple causes of functional dyspepsia have resulted in multiple drug target strategies for its treatment. DA-9701, a compound consisting of a combination of Corydalis Tuber and Pharbitidis Semen, has being developed for treatment of functional dyspepsia. It has multiple mechanisms of action such as fundus relaxation, visceral analgesia, and prokinetic effects. Furthermore, it was found to significantly enhance meal-induced gastric accommodation and increase gastric compliance in dogs. DA-9701 also showed an analgesic effect in rats with colorectal distension induced visceral hypersensitivity and an antinociceptive effect in beagle dogs with gastric distension-induced nociception. The pharmacological effects of DA-9701 also include conventional effects, such as enhanced gastric emptying and gastrointestinal transit. The safety profi le of DA-9701 is also preferable to that of other treatments.
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Affiliation(s)
- Yong Sam Kwon
- Dong-A ST Research Institute, Yongin 446-905, Republic of Korea
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7
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Liu J, Huang H, Xu X, Chen JDZ. Effects and possible mechanisms of acupuncture at ST36 on upper and lower abdominal symptoms induced by rectal distension in healthy volunteers. Am J Physiol Regul Integr Comp Physiol 2012; 303:R209-17. [PMID: 22592556 DOI: 10.1152/ajpregu.00301.2010] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Background acupuncture (AP) has been shown to have a therapeutic potential for gastrointestinal motility disorders. The aims of this study were to investigate the effects and possible mechanisms of acupuncture on postprandial upper and lower abdominal symptoms induced by rectal distension (RD). Twenty healthy volunteers were involved in a two-session study (AP and sham-AP, AP and no-AP, or sham-AP and no-AP). In 12 of the volunteers, RD was performed for 60 min in the postprandial state, and AP at ST36 or sham-AP was performed during the second 30-min period of RD. Gastric slow waves and heart rate variability (HRV) were recorded using the electrogastrogram and electrocardiogram, respectively. Upper and lower abdominal symptoms were scored during RD with AP and sham-AP. In five of the subjects, an additional experiment with two sessions (with AP and no-AP) was performed. In the remaining eight volunteers, the same experiment was performed with sham-AP and no-AP was performed. The results were, first, RD at an average volume of 171 ml induced upper and lower abdominal symptoms (P < 0.01). AP, but not sham-AP or no-AP, reduced both upper and lower abdominal symptoms (P < 0.05). Second, RD decreased the percentage of normal gastric slow waves (P < 0.05). AP improved gastric slow waves compared with sham-AP or no-AP (P < 0.05). Third, in the larger, but not smaller, sample size experiment, the vagal activity during the RD plus AP period was significantly higher than that during the RD alone period in the same session and the corresponding period with sham-AP or no-AP in other sessions (P < 0.05). Neither sham-AP nor no-AP showed any effects on vagal activity (P > 0.05). Finally, in the experiment with eight volunteers, neither sham-AP nor no-AP showed any effects on RD-induced impairment in gastric slow waves, abdominal symptoms, or vagal activity (P > 0.05). The conclusions are RD induces upper or lower abdominal symptoms and impairs gastric slow waves in healthy volunteers. AP at ST36 is able to improve upper and lower abdominal symptoms and impaired gastric slow waves induced by RD, possibly mediated via the vagal pathway.
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Affiliation(s)
- Jinsong Liu
- Division of Gastroenterology, Union Hospital of Huazhong Science & Technology University, Wuhan, China
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Yin J, Chen JDZ. Electroacupuncture improves rectal distension-induced delay in solid gastric emptying in dogs. Am J Physiol Regul Integr Comp Physiol 2011; 301:R465-72. [DOI: 10.1152/ajpregu.00271.2010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The aim of this study was to investigate the effects and mechanisms of electroacupuncture (EA) on rectal distension (RD)-induced delay in solid gastric emptying in dogs. Gastric emptying of solids was assessed in 12 dogs chronically implanted with a duodenal cannula by collecting samples at different time points from the cannula and measuring the dried weights of the samples. Bethanechol and atropine were used to qualitatively validate the method. In separate experiments, gastric emptying of solids was measured in a number of sessions: control, RD, RD + sham-EA, RD + EA of 6 mA, RD + EA of 3 mA, and RD + EA + naloxone. The method of gastric emptying by collecting and drying gastric chyme from the duodenal cannula was found to be accurate and reliable. Using the method, we found gastric emptying to be accelerated with bethanechol (70.01 ± 8.10% vs. 82.61 ± 4.15%, P = 0.04, vs. control) and delayed with atropine (4.31 ± 1.57%, P < 0.001, vs. control). RD substantially and significantly delayed gastric emptying. EA, but not sham-EA, attenuated delayed gastric emptying induced by RD (sham-EA: 48.79 ± 9.47% vs. EA: 74.28 ± 5.96%, P < 0.01). The effect was more potent with EA of 6 mA than EA of 3 mA and blocked by naloxone. EA is able to attenuate RD-induced delay in gastric emptying of solids, and this ameliorating effect may be mediated via the opioid pathway. EA may have a therapeutic potential for treating delayed gastric emptying attributed to lower gut distension.
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Affiliation(s)
- Jieyun Yin
- Division of Gastroenterology, University of Texas Medical Branch, Galveston, Texas
| | - Jiande D. Z. Chen
- Division of Gastroenterology, University of Texas Medical Branch, Galveston, Texas
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Lei Y, Chen JDZ. A potential and novel therapy for obesity: "appendix" electrical stimulation in dogs. Obes Surg 2010; 21:397-403. [PMID: 20890772 DOI: 10.1007/s11695-010-0281-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Intestinal electrical stimulation (IES) has been introduced as a potential therapy for obesity. However, it is unknown whether the effects of IES on gastrointestinal motility and food intake are location-specific. The aim of this study was to assess the effects of "appendix" (cecum in dog) electrical stimulation (AES) on gastric tone, gastric emptying, and food intake in dogs. METHODS Twelve healthy dogs were used in three experiments. In experiments 1 and 2, gastric tone and food intake were studied in six dogs implanted with a gastric cannula and one pair of stimulation electrodes in the "appendix." Experiment 3 was performed to study gastric emptying in six dogs with a duodenal cannula and one pair of stimulation electrodes in the "appendix." RESULTS (1) AES resulted in proximal gastric distention, with gastric volume increased from 114.9 ± 10.7 mL at baseline to 301.7 ± 37.1 mL during AES (p = 0.001), and the effect was completely blocked by a nitric oxide synthase inhibitor. (2) Gastric emptying was delayed at 90 min from 69.8 ± 9.5% in the control session to 15.2 ± 3.6% in the AES session (p = 0.002). 3) AES reduced food intake (average daily intake over a 1-week period) by 55.4% (550.4 ± 17.6 g at control vs. 245.7 ± 17.1 g with AES, p < 0.001). CONCLUSIONS AES reduces gastric tone via the nitrergic pathway, delays gastric emptying, and inhibits food intake in healthy dogs. These data suggest the therapeutic potential of AES for obesity. Additionally, AES is technically more feasible than electrical stimulation of the stomach or duodenum because a stimulator with electrodes may be placed into the appendix via colonoscopy.
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Affiliation(s)
- Yong Lei
- Veterans Research Foundation, VA Medical Center, Oklahoma City, OK, USA
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Sun Y, Song GQ, Yin J, Lei Y, Chen JDZ. Effects and mechanisms of gastrointestinal electrical stimulation on slow waves: a systematic canine study. Am J Physiol Regul Integr Comp Physiol 2009; 297:R1392-9. [PMID: 19710395 DOI: 10.1152/ajpregu.00006.2009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The aims of this study were to determine optimal pacing parameters of electrical stimulation on different gut segments and to investigate effects and possible mechanisms of gastrointestinal electrical stimulation on gut slow waves. Twelve female hound-mix dogs were used in this study. A total of six pairs of electrodes were implanted on the stomach, duodenum, and ascending colon. Bilateral truncal vagotomy was performed in six of the dogs. One experiment was designed to study the effects of the pacing frequency on the entrainment of gut slow waves. Another experiment was designed to study the modulatory effects of the vagal and sympathetic pathways on gastrointestinal pacing. The frequency of slow waves was 4.88 +/- 0.23 cpm (range, 4-6 cpm) in the stomach and 19.68 +/- 0.31 cpm (range, 18-22 cpm) in the duodenum. There were no consistent or dominant frequencies of the slow waves in the colon. The optimal parameters to entrain slow waves were: frequency of 1.1 intrinsic frequency (IF; 10% higher than IF) and pulse width of 150-450 ms (mean, 320.0 +/- 85.4 ms) for the stomach, and 1.1 IF and 10-20 ms for the small intestine. Electrical stimulation was not able to alter colon slow waves. The maximum entrainable frequency was 1.27 IF in the stomach and 1.21 IF in the duodenum. Gastrointestinal pacing was not blocked by vagotomy nor the application of an alpha- or beta-adrenergic receptor antagonist; whereas the induction of gastric dysrhythmia with electrical stimulation was completely blocked by the application of the alpha- or beta-adrenergic receptor antagonist. Gastrointestinal pacing is achievable in the stomach and small intestine but not the colon, and the maximal entrainable frequency of the gastric and small intestinal slow waves is about 20% higher than the IF. The entrainment of slow waves with gastrointestinal pacing is not modulated by the vagal or sympathetic pathways, suggesting a purely peripheral or muscle effect.
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Affiliation(s)
- Yan Sun
- Veterans Research and Education Foundation, Veterans Affairs Medical Center, Oklahoma City, Oklahoma 73104, USA
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11
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Chen J, Song GQ, Yin J, Koothan T, Chen JDZ. Electroacupuncture improves impaired gastric motility and slow waves induced by rectal distension in dogs. Am J Physiol Gastrointest Liver Physiol 2008; 295:G614-20. [PMID: 18653722 DOI: 10.1152/ajpgi.90322.2008] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Rectal distension (RD) is known to induce upper gastrointestinal (GI) symptoms. The aim of this study was to investigate the effects and underlying mechanisms of RD on gastric slow waves (GSW) and motor activity and furthermore to investigate the effects and mechanisms of electroacupuncture (EA) on GSW and motor activity. Eight female hound dogs chronically implanted with gastric serosal electrodes and a gastric fistula were studied in six separate sessions. Antral motility, GSW, heart rate variability, and rectal pressure were evaluated for the above purposes. 1) RD at a volume of 120 ml suppressed antral motility significantly. Guanethidine blocked the inhibitory effect of RD. EA at ST36 was able to restore the suppressed antral contractions induced by RD (16.6+/-1.7 vs. 8.0+/-1.4, P<0.001). Naloxone partially blocked the effect of EA on antral contractions. 2) RD reduced the percentage of normal GSW from 98.8+/-0.8% at baseline to 76.1+/-8.6% (P<0.05) that was increased to 91.8+/-3.0% with EA. The effects of EA on the GSW were nullified by the presence of naloxone. 3) EA did not show any significant effect on rectal pressure, suggesting that the ameliorating effects of EA on RD-induced impaired gastric motility were not due to a decrease in rectal pressure. 4) EA increased the vagal activity suppressed by RD. In conclusion, RD inhibits postprandial gastric motility and impairs GSW in dogs, and the inhibitory effects are mediated via the adrenergic pathways. EA at ST36 is able to restore the RD-induced impaired GSW and motor activities, possibly by enhancing vagal activity, and is partially mediated via the opioid pathway. EA may have therapeutic potential for functional gastrointestinal disorders.
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Affiliation(s)
- Jie Chen
- Division of Gastroenterology, University of Texas Medical Branch, Galveston, TX 77555-0632, USA.
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12
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Effect of smooth muscle tone on morphometry and residual strain in rat duodenum, jejunum and ileum. J Biomech 2008; 41:2667-72. [DOI: 10.1016/j.jbiomech.2008.06.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2008] [Revised: 06/05/2008] [Accepted: 06/10/2008] [Indexed: 11/22/2022]
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13
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Xu X, Lei Y, Liu S, Chen JDZ. Inhibitory effects of gastrointestinal electrical stimulation on rectal tone are both organ-specific and distance-related in dogs. Dis Colon Rectum 2008; 51:467-73. [PMID: 18175187 DOI: 10.1007/s10350-007-9129-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Revised: 07/22/2007] [Accepted: 08/11/2007] [Indexed: 02/08/2023]
Abstract
PURPOSE A phenomenon of cross-talk has been noted that electrical stimulation of one part of the gut affects another part of the gut. This study was designed to investigate whether the effect of electrical stimulation of one part of the gut on another part of the gut was related to the organ or the distance between the stimulation site and the affected organ, and the mechanism of ileum electrical stimulation on rectal tone. METHODS This study was performed in 13 healthy dogs (16-28 kg) in the fasting state. Experiments were performed to study 1) effects of gastric electrical stimulation, duodenal electrical stimulation, ileum electrical stimulation, and colonic electrical stimulation on rectal tone, and 2) the sympathetic and nitrergic pathways involved in the effects of ileum electrical stimulation on rectal tone. A computerized barostat was used to assess rectal tone. RESULTS All methods of stimulations significantly inhibited rectal tone. Duodenal electrical stimulation was least effective in reducing rectal tone. The percentage of increase in rectal volume was distance-related with duodenal electrical stimulation, ileum electrical stimulation, and colonic electrical stimulation but organ-specific with gastric electrical stimulation. The inhibitory effect of ileum electrical stimulation on rectal tone was abolished by N omega-nitro-L-arginine but not guanethidine. CONCLUSIONS Electrical stimulation of the stomach, intestine, or colon with long pulses has an inhibitory effect on rectal tone. This inhibitory effect is organ-specific as well as associated with the distance between stimulation site and affected organs. The inhibitory effect of ileum electrical stimulation on rectal tone is mediated by the nitrergic but not sympathetic pathway.
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Affiliation(s)
- Xiaohong Xu
- Veterans Research and Education Foundation, VA Medical Center, Oklahoma City, OK, USA
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