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Tan ZT, Ward M, Phillips RJ, Zhang X, Jaffey DM, Chesney L, Rajwa B, Baronowsky EA, McAdams J, Powley TL. Stomach region stimulated determines effects on duodenal motility in rats. Am J Physiol Regul Integr Comp Physiol 2021; 320:R331-R341. [PMID: 33470183 PMCID: PMC7988774 DOI: 10.1152/ajpregu.00111.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 12/11/2020] [Accepted: 01/12/2021] [Indexed: 01/14/2023]
Abstract
Gastric electrical stimulation (GES) is used clinically to promote proximal GI emptying and motility. In acute experiments, we measured duodenal motor responses elicited by GES applied at 141 randomly chosen electrode sites on the stomach serosal surface. Overnight-fasted (H2O available) anesthetized male rats (n = 81) received intermittent biphasic GES for 5 min (20-s-on/40-s-off cycles; I = 0.3 mA; pw = 0.2 ms; 10 Hz). A strain gauge on the serosal surface of the proximal duodenum of each animal was used to evaluate baseline motor activity and the effect of GES. Using ratios of time blocks compared with a 15-min prestimulation baseline, we evaluated the effects of the 5-min stimulation on concurrent activity, on the 10 min immediately after the stimulation, and on the 15-min period beginning with the onset of stimulation. We mapped the magnitude of the duodenal response (three different motility indices) elicited from the 141 stomach sites. Post hoc electrode site maps associated with duodenal responses suggested three zones similar to the classic regions of forestomach, corpus, and antrum. Maximal excitatory duodenal motor responses were elicited from forestomach sites, whereas inhibitory responses occurred with stimulation of the corpus. Moderate excitatory duodenal responses occurred with stimulation of the antrum. Complex, weak inhibitory/excitatory responses were produced by stimulation at boundaries between stomach regions. Patterns of GES efficacies coincided with distributions of previously mapped vagal afferents, suggesting that excitation of the duodenum is strongest when GES electrodes are situated over stomach concentrations of vagal intramuscular arrays, putative stretch receptors in the muscle wall.
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Affiliation(s)
- Zhenjun T Tan
- Department of Psychological Sciences, Purdue University, West Lafayette, Indiana
| | - Matthew Ward
- Department of Biomedical Engineering, Purdue University, West Lafayette, Indiana
| | - Robert J Phillips
- Department of Psychological Sciences, Purdue University, West Lafayette, Indiana
| | - Xueguo Zhang
- Clunbury Scientific LLC, Bloomfield Hills, Michigan
| | - Deborah M Jaffey
- Department of Psychological Sciences, Purdue University, West Lafayette, Indiana
| | - Logan Chesney
- Department of Psychological Sciences, Purdue University, West Lafayette, Indiana
| | - Bartek Rajwa
- Bindley Bioscience Center, Purdue University, West Lafayette, Indiana
| | | | - Jennifer McAdams
- Department of Psychological Sciences, Purdue University, West Lafayette, Indiana
| | - Terry L Powley
- Department of Psychological Sciences, Purdue University, West Lafayette, Indiana
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Effects of needling acupoints at different nerve segments on oxytocin neurons in rat’s hypothalamic paraventricular nucleus and intragastric pressure. JOURNAL OF ACUPUNCTURE AND TUINA SCIENCE 2019. [DOI: 10.1007/s11726-019-1128-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Berthoud HR, Neuhuber WL. Vagal mechanisms as neuromodulatory targets for the treatment of metabolic disease. Ann N Y Acad Sci 2019; 1454:42-55. [PMID: 31268181 PMCID: PMC6810744 DOI: 10.1111/nyas.14182] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/23/2019] [Accepted: 06/05/2019] [Indexed: 12/30/2022]
Abstract
With few effective treatments available, the global rise of metabolic diseases, including obesity, type 2 diabetes mellitus, and cardiovascular disease, seems unstoppable. Likely caused by an obesogenic environment interacting with genetic susceptibility, the pathophysiology of obesity and metabolic diseases is highly complex and involves crosstalk between many organs and systems, including the brain. The vagus nerve is in a key position to bidirectionally link several peripheral metabolic organs with the brain and is increasingly targeted for neuromodulation therapy to treat metabolic disease. Here, we review the basics of vagal functional anatomy and its implications for vagal neuromodulation therapies. We find that most existing vagal neuromodulation techniques either ignore or misinterpret the rich functional specificity of both vagal efferents and afferents as demonstrated by a large body of literature. This lack of specificity of manipulating vagal fibers is likely the reason for the relatively poor beneficial long‐term effects of such therapies. For these therapies to become more effective, rigorous validation of all physiological endpoints and optimization of stimulation parameters as well as electrode placements will be necessary. However, given the large number of function‐specific fibers in any vagal branch, genetically guided neuromodulation techniques are more likely to succeed.
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Affiliation(s)
- Hans-Rudolf Berthoud
- Neurobiology of Nutrition and Metabolism Department, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana
| | - Winfried L Neuhuber
- Institut fur Anatomie und Zellbiologie, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
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Dos-Santos RC, Reis LC, Perello M, Ferguson AV, Mecawi AS. The actions of ghrelin in the paraventricular nucleus: energy balance and neuroendocrine implications. Ann N Y Acad Sci 2019; 1455:81-97. [PMID: 31008525 DOI: 10.1111/nyas.14087] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/28/2019] [Accepted: 03/10/2019] [Indexed: 12/15/2022]
Abstract
Ghrelin is a peptide mainly produced and secreted by the stomach. Since its discovery, the impact of ghrelin on the regulation of food intake has been the most studied function of this hormone; however, ghrelin affects a wide range of physiological systems, many of which are controlled by the hypothalamic paraventricular nucleus (PVN). Several pathways may mediate the effects of ghrelin on PVN neurons, such as direct or indirect effects mediated by circumventricular organs and/or the arcuate nucleus. The ghrelin receptor is expressed in PVN neurons, and the peripheral or intracerebroventricular administration of ghrelin affects PVN neuronal activity. Intra-PVN application of ghrelin increases food intake and decreases fat oxidation, which chronically contribute to the increased adiposity. Additionally, ghrelin modulates the neuroendocrine axes controlled by the PVN, increasing the release of vasopressin and oxytocin by magnocellular neurons and corticotropin-releasing hormone by neuroendocrine parvocellular neurons, while possibly inhibiting the release of thyrotropin-releasing hormone. Thus, the PVN is an important target for the actions of ghrelin. Our review discusses the mechanisms of ghrelin actions in the PVN, and its potential implications for energy balance, neuroendocrine, and integrative physiological control.
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Affiliation(s)
- Raoni C Dos-Santos
- Department of Physiological Sciences, Federal Rural University of Rio de Janeiro, Seropédica, Brazil
| | - Luís C Reis
- Department of Physiological Sciences, Federal Rural University of Rio de Janeiro, Seropédica, Brazil
| | - Mario Perello
- Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology, La Plata, Argentina
| | - Alastair V Ferguson
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
| | - André S Mecawi
- Laboratory of Neuroendocrinology, Department of Biophysics, Paulista Medical School, Federal University of São Paulo, São Paulo, Brazil
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Long-Pulse Gastric Electrical Stimulation Repairs Interstitial Cells of Cajal and Smooth Muscle Cells in the Gastric Antrum of Diabetic Rats. Gastroenterol Res Pract 2018; 2018:6309157. [PMID: 30538740 PMCID: PMC6258098 DOI: 10.1155/2018/6309157] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2018] [Revised: 09/14/2018] [Accepted: 09/19/2018] [Indexed: 12/20/2022] Open
Abstract
Background/Aims The damage of interstitial cells of Cajal and smooth muscle cells has far-reaching implications in the pathogenesis of gastroparesis in diabetic patients. Gastric electrical stimulation (GES) is an efficient therapy for gastric motility disorders, but the mechanisms of GES require clarification. Methods Male rats were randomly divided into the control group, diabetic rat group (DM), diabetic rats with sham GES group (DM + SGES), and diabetic rats with different frequency GES group (DM + GES) (GES1: 5.5 cpm, 100 ms, 4 mA; GES2: 5.5 cpm, 300 ms, 4 mA; and GES3: 5.5 cpm, 550 ms, 2 mA). Gastric contractions were explored using the organ bath technique. The alterations of interstitial cells of Cajal, the SCF/c-kit pathway, and smooth muscle cells were also investigated. Results (1) Gastric contractions were significantly improved in the DM + GES group compared with those in the DM group. (2) The damage of interstitial cells of Cajal was prevented in the DM + GES group in contrast to the DM group. Moreover, long-pulse GES increased the expression of the SCF/c-kit pathway. More proliferated interstitial cells of Cajal in muscle layers were observed obviously in the DM + GES group. (3) The number of smooth muscle cells in the DM group was not significantly decreased compared with that in the control group. However, ultrastructural changes were distinctly damaged in the DM group. The application of GES protected against the alteration of the ultrastructures of smooth muscle cells. Conclusions Long-pulse GES improves gastric contraction possibly by enhancing the proliferation of interstitial cells of Cajal and restoring the injury of smooth muscle cells.
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Yan Y, Tian L, Xiang X, Ding W, Song G, Xu J. Chronic gastric electrical stimulation leads to weight loss via modulating multiple tissue neuropeptide Y, orexin, α-melanocyte-stimulating hormone and oxytocin in obese rats. Scand J Gastroenterol 2016. [PMID: 26199984 DOI: 10.3109/00365521.2015.1069391] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVES Gastric electrical stimulation (GES) has great potential for the treatment of obesity. We investigated the impact of chronic GES on the alteration of adipose tissue and the regulation of neuropeptide Y (NPY), orexin (OX), α-melanocyte-stimulating hormone (α-MSH) and oxytocin (OXT), and their receptors in several tissues. MATERIAL AND METHODS Most of the experiments included three groups of diet-induced obesity rats: (1) sham-GES (SGES); (2) GL-6mA (GES with 6 mA, 4 ms, 40 Hz, 2 s on, 3 s off at lesser curvature); and (3) SGES-PF (SGES rats receiving pair feeding to match the consumption of GL-6mA rats). Chronic GES was applied for 2 h every day for 4 weeks. During treatment with GES, food intake and body weight were monitored weekly. The alteration of epididymal fat weight, gastric emptying, and expression of peptides and their receptors in several tissues were determined. RESULTS GL-6mA was more potent than SGES-PF in decreasing body weight gain, epididymal fat tissue weight, adipocyte size and gastric emptying. Chronic GES significantly altered NPY, OX, α-MSH and OXT and their receptors in the hypothalamus, adipose tissue and stomach. CONCLUSIONS Chronic GES effectively leads to weight loss by reducing food intake, fat tissue weight and gastric emptying. NPY, α-MSH, orexin and OXT, and their receptors in the hypothalamus, adipose tissue and stomach appear to be involved in the anti-obesity effects of chronic GES.
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Affiliation(s)
- Yun Yan
- a 1 Department of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan 430022, China
| | - Lugao Tian
- a 1 Department of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan 430022, China
| | - Xuelian Xiang
- a 1 Department of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan 430022, China
| | - Wei Ding
- a 1 Department of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan 430022, China
| | - Gengqing Song
- b 2 Internal Medicine Department, Texas Tech University Health Sciences Center, Paul L. Foster School of Medicine , El Paso, TX, USA
| | - Junying Xu
- a 1 Department of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology , Wuhan 430022, China
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Yong CY, Chen S, Chen H, Chu X, Zhang C, Tan C, Ye L, Li JS. Central neuromechanisms underlying control of intragastric pressure through acupuncture at Zusanli (ST36) in rats: the upper cervical cord is the key link between the ascending and descending pathways. Neural Regen Res 2016; 11:971-6. [PMID: 27482227 PMCID: PMC4962596 DOI: 10.4103/1673-5374.184497] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Sensory inputs stimulated by Zusanli (ST36) acupuncture in the abdomen are known to converge in the upper cervical cord. However, it is unclear whether these inputs are subsequently conveyed to the hypothalamic paraventricular nucleus and what kind of afferent fibers are involved. We focused on the upper cervical cord, where afferent inputs converge, and detected c-fos expression in oxytocinergic neurons. We found that Zusanli acupuncture therapy effectively elevated intragastric pressure, but inhibited expression of c-fos in oxytocinergic neurons of the paraventricular nucleus in upper cervical cord injured rats. These Zusanli acupuncture effects remained even after complete dorsal cord transection. However, after complete transection of the spinal cord or dorsolateral funiculus, the effects were significantly attenuated and even disappeared. These findings suggest that the paraventricular nucleus is responsible for pooling and integrating signals from the Zusanli acupuncture and sensory information from the intragastric pressure variation, thereby contributing to the regulation of intragastric pressure. The upper cervical cord serves as the key link between ascending and descending pathways, which conveys afferent inputs to the paraventricular nucleus through the dorsolateral funiculus.
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Affiliation(s)
- Chun-Yan Yong
- Department of Integrative Medicine, Xiangya Hospital of Central South University, Changsha, Hunan Province, China
| | - Shu Chen
- School of Acupuncture and Massage, Hunan University of Chinese Medicine, Changsha, Hunan Province, China
| | - Heng Chen
- School of Acupuncture and Massage, Hunan University of Chinese Medicine, Changsha, Hunan Province, China
| | - Xiao Chu
- School of Acupuncture and Massage, Hunan University of Chinese Medicine, Changsha, Hunan Province, China
| | - Chao Zhang
- School of Acupuncture and Massage, Hunan University of Chinese Medicine, Changsha, Hunan Province, China
| | - Cheng Tan
- School of Acupuncture and Massage, Hunan University of Chinese Medicine, Changsha, Hunan Province, China
| | - Lan Ye
- School of Acupuncture and Massage, Hunan University of Chinese Medicine, Changsha, Hunan Province, China
| | - Jiang-Shan Li
- School of Acupuncture and Massage, Hunan University of Chinese Medicine, Changsha, Hunan Province, China
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Stijnen P, Ramos-Molina B, O'Rahilly S, Creemers JWM. PCSK1 Mutations and Human Endocrinopathies: From Obesity to Gastrointestinal Disorders. Endocr Rev 2016; 37:347-71. [PMID: 27187081 DOI: 10.1210/er.2015-1117] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Prohormone convertase 1/3, encoded by the PCSK1 gene, is a serine endoprotease that is involved in the processing of a variety of proneuropeptides and prohormones. Humans who are homozygous or compound heterozygous for loss-of-function mutations in PCSK1 exhibit a variable and pleiotropic syndrome consisting of some or all of the following: obesity, malabsorptive diarrhea, hypogonadotropic hypogonadism, altered thyroid and adrenal function, and impaired regulation of plasma glucose levels in association with elevated circulating proinsulin-to-insulin ratio. Recently, more common variants in the PCSK1 gene have been found to be associated with alterations in body mass index, increased circulating proinsulin levels, and defects in glucose homeostasis. This review provides an overview of the endocrinopathies and other disorders observed in prohormone convertase 1/3-deficient patients, discusses the possible biochemical basis for these manifestations of the disease, and proposes a model whereby certain missense mutations in PCSK1 may result in proteins with a dominant negative action.
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Affiliation(s)
- Pieter Stijnen
- Laboratory for Biochemical Neuroendocrinology (P.S., B.R.-M., J.W.M.C.), Department of Human Genetics, KU Leuven, Leuven 3000, Belgium; and Medical Research Council (MRC) Metabolic Diseases Unit (S.O.), Wellcome Trust-MRC Institute of Metabolic Science, National Institute for Health Research, Cambridge Biomedical Research Centre, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Bruno Ramos-Molina
- Laboratory for Biochemical Neuroendocrinology (P.S., B.R.-M., J.W.M.C.), Department of Human Genetics, KU Leuven, Leuven 3000, Belgium; and Medical Research Council (MRC) Metabolic Diseases Unit (S.O.), Wellcome Trust-MRC Institute of Metabolic Science, National Institute for Health Research, Cambridge Biomedical Research Centre, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Stephen O'Rahilly
- Laboratory for Biochemical Neuroendocrinology (P.S., B.R.-M., J.W.M.C.), Department of Human Genetics, KU Leuven, Leuven 3000, Belgium; and Medical Research Council (MRC) Metabolic Diseases Unit (S.O.), Wellcome Trust-MRC Institute of Metabolic Science, National Institute for Health Research, Cambridge Biomedical Research Centre, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - John W M Creemers
- Laboratory for Biochemical Neuroendocrinology (P.S., B.R.-M., J.W.M.C.), Department of Human Genetics, KU Leuven, Leuven 3000, Belgium; and Medical Research Council (MRC) Metabolic Diseases Unit (S.O.), Wellcome Trust-MRC Institute of Metabolic Science, National Institute for Health Research, Cambridge Biomedical Research Centre, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
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Yan Y, Xiang XL, Qian W, Xu JY, Hou XH. Changes of neuronal activities after gut electrical stimulation with different parameters and locations in lateral hypothalamus area of obese rats. ACTA ACUST UNITED AC 2014; 34:510-515. [PMID: 25135719 DOI: 10.1007/s11596-014-1307-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 06/10/2014] [Indexed: 12/12/2022]
Abstract
This study tested the effects of the gastrointestinal pulse train electrical stimulation with different parameters and at different locations on the neuronal activities of the lateral hypothalamus area (LHA) in obese rats in order to find the optimal stimulation parameter and location. Eight gastric electrical stimulations (GES) with different parameters were performed and the neuronal activities of gastric-distension responsive (GD-R) neurons in LHA were observed. The effects of stimulations with 8 parameters were compared to find the optimal parameter. Then the optimal parameter was used to perform electrical stimulation at duodenum and ileum, and the effects of the duodenal and ileac stimulation on the GD-R neurons in LHA were compared with the gastric stimulation of optimal parameter. The results showed that GES with the lowest energy parameter (0.3 ms, 3 mA, 20 Hz, 2 s on, 3 s off) activated the least neurons. The effects of GES with other parameters whose pulse width was 0.3 ms were not significantly different from those of the lowest energy parameter. Most gastric stimulations whose pulse width was 3 ms activated more LHA neurons than the smallest energy parameter stimulation, and the effects of those 3 ms gastric stimulations were similar. Accordingly, the lowest energy parameter was recognized as the optimal parameter. The effects of stimulations with the optimal parameter at stomach, duodenum and ileum on the LHA neuronal activities were not different. Collectively, gastrointestinal electrical stimulation (GIES) with relatively large pulse width might have stronger effects to the neuronal activities of GD-R neurons in LHA of obese rats. The effects of the GIES at different locations (stomach, duodenum and ileum) on those neurons are similar, and GES is preferential because of its easy clinical performance and safety.
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Affiliation(s)
- Yun Yan
- Department of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Xue-Lian Xiang
- Department of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Wei Qian
- Department of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Jun-Ying Xu
- Department of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
| | - Xiao-Hua Hou
- Department of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
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Abstract
Background Gastric electrical stimulation (GES) has been proposed as a promising therapeutic option in treating obesity for 20 years. Currently, the available device of GES cannot meet the clinical needs. The purpose of this study is to verify the effect of a new type of adjustable gastric electrical stimulator in reducing food intake and body weight. Methods Eight beagle dogs randomly followed GES and sham GES for 3 months in a crossover design. Parameters were adjusted and individualized during the experiment. Symptoms of GES were recorded, and the effective parameters were selected. Resistance to GES was assessed. Food intake and body weight were measured to evaluate the effect of GES. Results The effective parameters were varied among the dogs. Resistance to GES was observed in different periods in dogs. Parameters needed to be adjusted every 10.2 ± 2.1 days during the period of GES. Food intake during GES for 3 months was significantly reduced than that during sham GES of 3 months (P < 0.05). With the decreased food intake, body weight was significantly reduced by the end of GES of 3 months compared with that of sham GES of 3 months (P < 0.05). Conclusions Food intake and body weight of dogs are significantly reduced by adjustable GES. Individual parameters and resistance during GES are required to be considered. The new adjustable device may have good prospects of clinical application for obesity.
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Abstract
Obesity and its associated metabolic disorders are growing health concerns in the US and worldwide. In the US alone, more than two-thirds of the adult population is classified as either overweight or obese [1], highlighting the need to develop new, effective treatments for these conditions. Whereas the hormone oxytocin is well known for its peripheral effects on uterine contraction during parturition and milk ejection during lactation, release of oxytocin from somatodendrites and axonal terminals within the central nervous system (CNS) is implicated in both the formation of prosocial behaviors and in the control of energy balance. Recent findings demonstrate that chronic administration of oxytocin reduces food intake and body weight in diet-induced obese (DIO) and genetically obese rodents with impaired or defective leptin signaling. Importantly, chronic systemic administration of oxytocin out to 6 weeks recapitulates the effects of central administration on body weight loss in DIO rodents at doses that do not result in the development of tolerance. Furthermore, these effects are coupled with induction of Fos (a marker of neuronal activation) in hindbrain areas (e.g. dorsal vagal complex (DVC)) linked to the control of meal size and forebrain areas (e.g. hypothalamus, amygdala) linked to the regulation of food intake and body weight. This review assesses the potential central and peripheral targets by which oxytocin may inhibit body weight gain, its regulation by anorexigenic and orexigenic signals, and its potential use as a therapy that can circumvent leptin resistance and reverse the behavioral and metabolic abnormalities associated with DIO and genetically obese models.
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Affiliation(s)
- James E Blevins
- VA Puget Sound Health Care System, Office of Research and Development Medical Research Service, Department of Veterans Affairs Medical Center, Seattle, WA, 98108, USA,
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Li S, Maude-Griffin R, Sun Y, Starkebaum W, Chen JDZ. Food intake and body weight responses to intermittent vs. continuous gastric electrical stimulation in diet-induced obese rats. Obes Surg 2013; 23:71-9. [PMID: 23001597 DOI: 10.1007/s11695-012-0773-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Gastric electrical stimulation (GES) has recently been introduced as a potential therapy for the treatment of obesity. The main challenge for the new generation of devices is to achieve desired clinical outcomes at a suitably low level of energy consumption. The aim of this study is to compare the effectiveness of GES with continuous and intermittent duty cycles in reducing food intake and body weight in diet-induced obesity-prone rats. METHODS In macro duty cycle experiment, 40 rats were divided into groups to receive a sham GES, continuous GES, or intermittent GES (15 min On-45 min Off or 15 min On-15 min Off) for 28 days. In micro duty cycle experiment, 18 rats received cross-over treatment of continuous stimulation, 60 % time cycle or 40 % time cycle. Food intake, body weight, gastric emptying and ghrelin level were measured to evaluate the effect of different GES. RESULTS GES with macro duty cycle intensity-dependently reduced mean daily food intake increase by 18.6, 10.2 and -6.0 % compared to 42.7 % with sham GES and body weight gain by 6.1 %, 3.4 and -0.8 % compared to 5 % with sham GES. Daily food intake decreased with increasing micro duty cycle intensity, averaging 16.5, 15.6 and 13.7 g/day under 40 % cycle, 60 % cycle and continuous stimulation respectively. Gastric emptying was intensity-dependently delayed by GES. GES has no effect in modulating plasma ghrelin level. CONCLUSIONS GES energy-dependently reduces food intake, body weight and gastric emptying. Peripheral modulation of plasma ghrelin level is not related to the GES effects.
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Affiliation(s)
- Shiying Li
- Veterans Research and Education Foundation, VA Medical Center, Oklahoma City, OK, USA
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Hypothalamic neuropeptides and the regulation of appetite. Neuropharmacology 2012; 63:18-30. [PMID: 22369786 DOI: 10.1016/j.neuropharm.2012.02.004] [Citation(s) in RCA: 163] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Revised: 12/23/2011] [Accepted: 02/07/2012] [Indexed: 12/24/2022]
Abstract
Neuropeptides released by hypothalamic neurons play a major role in the regulation of feeding, acting both within the hypothalamus, and at other appetite regulating centres throughout the brain. Where classical neurotransmitters signal only within synapses, neuropeptides diffuse over greater distances affecting both nearby and distant neurons expressing the relevant receptors, which are often extrasynaptic. As well as triggering a behavioural output, neuropeptides also act as neuromodulators: altering the response of neurons to both neurotransmitters and circulating signals of nutrient status. The mechanisms of action of hypothalamic neuropeptides with established roles in feeding, including melanin-concentrating hormone (MCH), the orexins, α-melanocyte stimulating hormone (α-MSH), agouti-gene related protein (AgRP), neuropeptide Y, and oxytocin, are reviewed in this article, with emphasis laid on both their effects on appetite regulating centres throughout the brain, and on examining the evidence for their physiological roles. In addition, evidence for the involvement of several putative appetite regulating hypothalamic neuropeptides is assessed including, ghrelin, cocaine and amphetamine-regulated transcript (CART), neuropeptide W and the galanin-like peptides. This article is part of a Special Issue entitled 'Central control of Food Intake'.
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Zhang J, Maude-Griffin R, Zhu H, Sun Y, Starkebaum W, Firestone E, Chen JDZ. Gastric electrical stimulation parameter dependently alters ventral medial hypothalamic activity and feeding in obese rats. Am J Physiol Gastrointest Liver Physiol 2011; 301:G912-8. [PMID: 21852365 DOI: 10.1152/ajpgi.00487.2010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Gastric electrical stimulation (GES) has been used to treat obesity with unclear mechanisms and limited parameter ranges. This study explores effects of GES parameters on ventral medial hypothalamic (VMH) activity, feeding, and body weight in diet-induced obese (DIO) rats. For experiment 1, discharge rates were recorded in 39 gastric distension-responsive (GD-R) neurons in 12 DIO rats. Basal rates were compared with rates under GES using varied pulse amplitudes, widths, frequencies, and train-on times. For experiment 2, a crossover experiment in 16 DIO rats measured food intake and weight effects of GES pulse width, the parameter with the steepest neuronal response gradient in experiment 1. Treatments were sham and 0.5-, 2.0-, and 5.0-ms pulse GES. In experiment 1, 11 of 13 GES parameter sets tested produced significantly (P < 0.05) altered discharge rates of GD-R neurons. Increases in pulse amplitude (P < 0.05) and width (P < 0.0001) produced significant upward linear trends in response over the range tested, with the trend being strongest for pulse width. In experiment 2, over 4 days of 0.5-, 2.0-, and 5.0-ms GES treatment, food intake was 9.6% (P < 0.05), 21.0% (P < 0.0001), and 47.3% (P < 0.0001) lower than under sham-GES, whereas body weight changes were 0.7 (P = 0.48), 2.2 (P < 0.05), and 3.5 (P < 0.002) percentage points lower, respectively. We concluded that GES pulse width increases had the largest effect on VMH neuronal activity, and these effects were paralleled by pulse width-dependent reductions in food intake and body weight. Lengthening pulse width beyond the range used in prior clinical studies may be critical to making GES a viable obesity treatment.
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Affiliation(s)
- Jing Zhang
- Veterans Research and Education Foundation, VA Medical Center, Oklahoma City, Oklahoma, USA
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15
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Gallas S, Fetissov SO. Ghrelin, appetite and gastric electrical stimulation. Peptides 2011; 32:2283-9. [PMID: 21672567 DOI: 10.1016/j.peptides.2011.05.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 05/26/2011] [Accepted: 05/27/2011] [Indexed: 12/18/2022]
Abstract
Ghrelin is a peptide hormone produced mainly by the stomach and has widespread physiological functions including increase in appetite. The stimulation of the ghrelin system represents a potential therapeutic approach in various disorders characterized by deficient ghrelin signaling or by low appetite. This stimulation may be achieved via pharmacological targeting of the ghrelin receptor with synthetic ghrelin or ghrelin mimetics or via increased endogenous ghrelin production. Recently, it was demonstrated that gastric electrical stimulation (GES) with Enterra parameters results in increased ghrelin production in rats. Furthermore, recent data revealed putative role of ghrelin-reactive immunoglobulins in the modulation of the ghrelin signaling which can be also stimulated by GES. Here, we review the links between GES and ghrelin in existing GES experimental and clinical applications for treatment of gastroparesis, functional dyspepsia or obesity and discuss if GES can be proposed as a non-pharmacological approach to improve ghrelin secretion in several pathological conditions characterized by low appetite, such as anorexia nervosa or anorexia-cachexia syndrome.
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Affiliation(s)
- Syrine Gallas
- Digestive System & Nutrition Laboratory, ADEN EA4311, Rouen University, IFR23, Rouen 76183, France
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16
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Furness JB, Hunne B, Matsuda N, Yin L, Russo D, Kato I, Fujimiya M, Patterson M, McLeod J, Andrews ZB, Bron R. Investigation of the presence of ghrelin in the central nervous system of the rat and mouse. Neuroscience 2011; 193:1-9. [PMID: 21835225 DOI: 10.1016/j.neuroscience.2011.07.063] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 07/25/2011] [Accepted: 07/25/2011] [Indexed: 11/25/2022]
Abstract
Ghrelin and ghrelin receptor agonist have effects on central neurons in many locations, including the hypothalamus, caudal brain stem, and spinal cord. However, descriptions of the distributions of ghrelin-like immunoreactivity in the CNS in published work are inconsistent. We have used three well-characterized anti-ghrelin antibodies, an antibody to the unacylated form of ghrelin, and a ghrelin peptide assay in rats, mice, ghrelin knockout mice, and ghrelin receptor reporter mice to re-evaluate ghrelin presence in the rodent CNS. The stomach served as a positive control. All antibodies were effective in revealing gastric endocrine cells. However, no specific staining could be found in the brain or spinal cord. Concentrations of antibody 10 to 30 times those effective in the stomach bound to nerve cells in rat and mouse brain, but this binding was not reduced by absorbing concentrations of ghrelin peptide, or by use of ghrelin gene knockout mice. Concentrations of ghrelin-like peptide, detected by enzyme-linked immunosorbent assay in extracts of hypothalamus, were 1% of gastric concentrations. Ghrelin receptor-expressing neurons had no adjacent ghrelin immunoreactive terminals. It is concluded that there are insignificant amounts of authentic ghrelin in neurons in the mouse or rat CNS and that ghrelin receptor-expressing neurons do not receive synaptic inputs from ghrelin-immunoreactive nerve terminals in these species.
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Affiliation(s)
- J B Furness
- Department of Anatomy and Cell Biology, University of Melbourne, Parkville, Victoria 3010, Australia.
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