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Wang C, Han X, Sun X, Guo F, Luan X, Xu L. Orexin-A signaling in the paraventricular nucleus promote gastric acid secretion and gastric motility through the activation neuropeptide Y Y 1 receptors and modulated by the hypothalamic lateral area. Neuropeptides 2019; 74:24-33. [PMID: 30700376 DOI: 10.1016/j.npep.2019.01.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Revised: 01/22/2019] [Accepted: 01/22/2019] [Indexed: 01/23/2023]
Abstract
OBJECTIVE Abnormal gastric acid secretion and gastric dyskinesia are common gastroenterological ailments. Our study aims to investigate the effect of orexin-A in the paraventricular nucleus (PVN) gastric motility and gastric acid secretion. METHODS The source of orexin-A neuronal projections to the PVN were explored by retrograde tracing and fluorescence immunohistochemistry experiments. Neuronal discharge recordings of single cells were taken within the PVN. Gastric motility was recorded using a force transducer implanted into the stomach, and gastric acid secretion measured through a pyloric catheter. RESULTS Orexin-A-positive neuronal projections from LHA to PVN were found. Administration of orexin-A to PVN activated the firing of 63.2% NPY-excited/GD-excitatory (GD-E) neurons but suppressed the firing of 55.9% NPY-inhibited/GD-inhibitory (GD-I) neurons, promoted gastric motility and gastric acid secretion in a dose-dependent manner. Responses produced by orexin-A could be partially blocked by Y1 receptor antagonist GR-231118; Electrical stimulation to the the hypothalamic lateral area (LHA) altered NPY-sensitive/GD neuronal activity in the PVN, stimulated gastric motility and gastric acid secretion. Additionally, these effects induced by LHA electrical stimulation were blocked by administration of the OX1R antagonist SB-334867 to the PVN. CONCLUSION Orexin-A from LHA neurons act on the PVN to enhance gastric motility and gastric acid secretion, with Y1 receptor signaling playing a critical role.
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Affiliation(s)
- Cheng Wang
- Qingdao University, School of Basic Medical Sciences, Shandong, Qingdao 266071, China
| | - Xiaohua Han
- Qingdao University, School of Basic Medical Sciences, Shandong, Qingdao 266071, China
| | - Xiangrong Sun
- Qingdao University, School of Basic Medical Sciences, Shandong, Qingdao 266071, China
| | - Feiei Guo
- Qingdao University, School of Basic Medical Sciences, Shandong, Qingdao 266071, China
| | - Xiao Luan
- Qingdao University, School of Basic Medical Sciences, Shandong, Qingdao 266071, China
| | - Luo Xu
- Qingdao University, School of Basic Medical Sciences, Shandong, Qingdao 266071, China.
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Shareghi Brojeni M, Salimi M, Mirmohammadsadeghi Z, Haghparast A, Eliassi A. Comparison of Effects of Light Anesthetics, Diethyl Ether and Carbon Dioxide, on Hypothalamic Paraventricular Nucleus D 1 and D 2 Dopamine Receptors- and Glucosensitive Neurons-Induced Food Intake in Fasted Conscious Rats. Basic Clin Neurosci 2018; 9:269-274. [PMID: 30519385 PMCID: PMC6276533 DOI: 10.32598/bcn.9.4.269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 05/15/2017] [Accepted: 07/30/2017] [Indexed: 11/20/2022] Open
Abstract
Introduction Carbon Dioxide (CO2) and diethyl ether are used as light anesthetics. However, experimental data about their side effects are scarce. In addition, in all our previous works on regulatory mechanisms of hypothalamus during food intake, including the effect of Paraventricular Nucleus (PVN) D1 and D2 dopamine receptors and glucosensitive neurons, the drug injections were performed under brief diethyl ether anesthesia. In the current study, we tested the hypothesis which postulates that CO2 and diethyl ether as light anesthetic agents affect the stimulatory effect of PVN dopamine receptors and glucosensitive neurons in feeding behavior. Methods Male Wistar rats were implanted with guide cannula directed to their PVN. Glucose (0.8 μg), SKF38393 (D1 agonist, 0.5 μg), quinpirole (D2 agonist, 0.3 μg) and saline (0.3 μL) were microinjected into the PVN and food intake was measured over 1 hour. Results Our results showed that CO2 but not diethyl ether decreased food intake compared to intact animals. The PVN injections of glucose, SKF38393, and quinpirole increased food intake under brief diethyl ether anesthesia. In contrast, the PVN microinjected glucose-induced and dopamine receptor agonists-induced food intake were inhibited under light CO2 anesthesia. Conclusion Our results suggest that brief exposure to CO2 and diethyl ether as light anesthetic agents may affect PVN glucosensing neurons-induced and dopamine receptors-induced food intake in fasted rats.
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Affiliation(s)
- Masoud Shareghi Brojeni
- Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Morteza Salimi
- Department of Physiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Zahra Mirmohammadsadeghi
- Department of Physiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Abbas Haghparast
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Afsaneh Eliassi
- Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Department of Physiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Hao H, Luan X, Guo F, Sun X, Gong Y, Xu L. Lateral hypothalamic area orexin-A influence the firing activity of gastric distension-sensitive neurons and gastric motility in rats. Neuropeptides 2016; 57:45-52. [PMID: 26919916 DOI: 10.1016/j.npep.2016.02.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 02/05/2016] [Accepted: 02/14/2016] [Indexed: 12/13/2022]
Abstract
The orexins system consists of two G-protein coupled receptors (the orexin-1 and the orexin-2 receptor) and two neuropeptides, orexin-A and orexin-B. Orexin-A is an excitatory neuropeptide that regulates arousal, wakefulness and appetite. Recent studies have shown that orexin-A may promote gastric motility. We aim to explore the effects of orexin-A on the gastric -distension (GD) sensitive neurons and gastric motility in the lateral hypothalamic area (LHA), and the possible regulation by the paraventricular nucleus (PVN). Extracellular single unit discharges were recorded and the gastric motility was monitored by administration of orexin-A into the LHA and electrical stimulation of the PVN. There were GD neurons in the LHA, and administration of orexin-A to the LHA could increase the firing rate of both GD-excitatory (GD-E) and GD-inhibited (GD-I) neurons. The gastric motility was significantly enhanced by injection of orexin-A into the LHA with a dose dependent manner, which could be completely abolished by pre-treatment with orexin-A receptor antagonist SB334867. Electrical stimulation of the PVN could significantly increase the firing rate of GD neurons responsive to orexin-A in the LHA as well as promote gastric motility of rats. However, those effects could be partly blocked by pre-treatment with SB334867 in the LHA. It is suggested that orexin-A plays an important role in promoting gastric motility via LHA. The PVN may be involved in regulation of LHA on gastric motility.
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Affiliation(s)
- Heling Hao
- Department of Pathophysiology, Medical College of Qingdao University, Qingdao, Shandong 266021, PR China
| | - Xiao Luan
- Department of Pathophysiology, Medical College of Qingdao University, Qingdao, Shandong 266021, PR China
| | - Feifei Guo
- Department of Pathophysiology, Medical College of Qingdao University, Qingdao, Shandong 266021, PR China
| | - Xiangrong Sun
- Department of Pathophysiology, Medical College of Qingdao University, Qingdao, Shandong 266021, PR China
| | - Yanling Gong
- Department of Pharmacy, College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, Shandong, PR China
| | - Luo Xu
- Department of Pathophysiology, Medical College of Qingdao University, Qingdao, Shandong 266021, PR China.
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Li J, Hu Z, de Lecea L. The hypocretins/orexins: integrators of multiple physiological functions. Br J Pharmacol 2014; 171:332-50. [PMID: 24102345 DOI: 10.1111/bph.12415] [Citation(s) in RCA: 181] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2013] [Revised: 07/16/2013] [Accepted: 08/02/2013] [Indexed: 12/28/2022] Open
Abstract
The hypocretins (Hcrts), also known as orexins, are two peptides derived from a single precursor produced in the posterior lateral hypothalamus. Over the past decade, the orexin system has been associated with numerous physiological functions, including sleep/arousal, energy homeostasis, endocrine, visceral functions and pathological states, such as narcolepsy and drug abuse. Here, we review the discovery of Hcrt/orexins and their receptors and propose a hypothesis as to how the orexin system orchestrates these multifaceted physiological functions.
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Affiliation(s)
- Jingcheng Li
- Department of Physiology, Third Military Medical University, Chongqing, China
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Abstract
Hypocretins, also named as orexins, are excitatory neuropeptides secreted by neurons specifically located in lateral hypothalamus and perifornical areas. Orexinergic fibers are extensively distributed in various brain regions and involved in a number of physiological functions, such as arousal, cognition, stress, appetite, and metabolism. Arousal is the most important function of orexin system as dysfunction of orexin signaling leads to narcolepsy. In addition to narcolepsy, orexin dysfunction is associated with serious neural disorders, including addiction, depression, and anxiety. However, some results linking orexin with these disorders are still contradictory, which may result from differences of detection methods or the precision of tools used in measurements; strategies targeted to orexin system (e.g., antagonists to orexin receptors, gene delivery, and cell transplantation) are promising new tools for treatment of neuropsychiatric disorders, though studies are still in a stage of preclinical or clinical research.
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Affiliation(s)
- Quanhui Chen
- Department of Physiology, Third Military Medical University, Chongqing 400038, China; Department of Sleep and Psychology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing 400038, China
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Abstract
Hypoglycemia produces complex neural and hormonal responses that restore glucose levels to normal. Glucose, metabolic substrates and their transporters, neuropeptides and neurotransmitters alter the firing rate of glucose-sensing neurons in the ventromedial hypothalamus (VMH); these monitor energy status and regulate the release of neurotransmitters that instigate a suitable counter-regulatory response. Under normal physiological conditions, these mechanisms maintain blood glucose concentrations within narrow margins. However, antecedent hypoglycemia and diabetes can lead to adaptations within the brain that impair counter-regulatory responses. Clearly, the mechanisms employed to detect and regulate the response to hypoglycemia, and the pathophysiology of defective counter-regulation in diabetes, are complex and need to be elucidated to permit the development of therapies that prevent or reduce the risk of hypoglycemia.
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Affiliation(s)
- Owen Chan
- Yale University School of Medicine, Department of Internal Medicine - Section of Endocrinology, New Haven, CT, 06520 U.S.A
| | - Robert Sherwin
- Yale University School of Medicine, Department of Internal Medicine - Section of Endocrinology, New Haven, CT, 06520 U.S.A
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Kermani M, Eliassi A. Gastric acid secretion induced by paraventricular nucleus microinjection of orexin A is mediated through activation of neuropeptide Yergic system. Neuroscience 2012; 226:81-8. [PMID: 22986171 DOI: 10.1016/j.neuroscience.2012.08.052] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 08/05/2012] [Accepted: 08/22/2012] [Indexed: 12/25/2022]
Abstract
UNLABELLED Very recently, we have reported that the modulatory effect of PVN on gastric acid secretion may be mediated through the orexin fibers and/or orexin-responsive neurons. In this study, we address the hypothesis which demonstrates the existence of a putative orexin A - neuropeptide Y Y1/Y5 receptors interaction to increase gastric acid secretion in pyloric-ligated conscious rats. Male Wistar rats were implanted with guide canula directed to the PVN and lateral ventricle. Intracerebroventricular (ICV) microinjections of GR-231118 (Y1 receptor antagonist) and CGP-71683 (Y5 receptor antagonist) on gastric acid secretion were considered. The effect of pretreatment with Y1 receptor antagonist, GR-231118, and Y5 receptor antagonist, CGP-71683, on PVN orexin A-induced acid secretion was assessed. Gastric acid secretion was measured using the pylorus-ligation method, and the amount of gastric acid was determined by titration with 0.01N NaOH to a pH of 7.0. KEY RESULTS ICV microinjections of GR-231118 and CGP-71683 decreased acid secretion by 25±0.05% and 67±0.02%, respectively. ICV microinjections of GR-231118 and CGP-71683 inhibited effects of PVN-injected orexin-A on acid secretion. We suggest that Y1 and Y5 receptors stimulate gastric acid secretion and the stimulatory effect of PVN orexin receptors on gastric acid secretion may be mediated via interactions, at least in part, through activation of Y1 and Y5 receptors. These neural pathways may play key roles in the orexinergic action of orexins in the cephalic phase of gastric acid secretion.
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Affiliation(s)
- M Kermani
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Chaleek N, Kermani M, Eliassi A, Haghparast A. Effects of orexin and glucose microinjected into the hypothalamic paraventricular nucleus on gastric acid secretion in conscious rats. Neurogastroenterol Motil 2012; 24:e94-102. [PMID: 22004243 DOI: 10.1111/j.1365-2982.2011.01789.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND Orexin-A is a novel peptide that appears to play a role in regulation of gastric acid secretion. However, little is known about sites of its action. In addition, evidences suggest that some of orexin-A neurons respond to glucose. In this study, we address the hypothesis which demonstrates that orexin-A and glucose act in the hypothalamic paraventricular nucleus (PVN) to increase gastric acid secretion and juice volume in pyloric-ligated conscious rats. METHODS Male Wistar rats were implanted with guide canula directed to the PVN. Orexin-A (3-10 μg), glucose (350-750 ng) SB334867 (6-20 μg) were microinjected. The effect of pretreatment with an orexin-1 receptor antagonist, SB334867, on orexin-A and D-glucose induced acid secretion was assessed. Gastric acid secretion was measured using the pylorus-ligation method, and the amount of gastric acid was determined by titration with 0.01 N NaOH to a pH of 7.0. KEY RESULTS Intraparaventricular injection of orexin-A or D-glucose stimulated gastric acid secretion in a dose-dependent manner. The PVN injections of orexin-A receptor antagonist, SB334867, were associated with gastric acid secretion decrease and inhibited effects of PVN-injected orexin-A. Orexin-stimulated gastric acid secretion was decreased (~40%) after PVN lesions. Glucose-stimulated gastric acid secretion was also suppressed by intraperitoneal (IP) injection of SB334867. In addition, it was observed that co-injection of orexin-A and glucose at ineffective doses increased gastric secretion significantly. CONCLUSIONS & INFERENCES We suggest that orexin-A and glucose effects on the PVN stimulate gastric acid secretion. This stimulatory effect is probably mediated by orexin-1 receptors.
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Affiliation(s)
- N Chaleek
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Abstract
PURPOSE OF REVIEW Update on the role of gastrointestinal peptides in regulating gastric acid secretion. RECENT FINDINGS A novel transgenic mouse that expresses the entire human gastrin gene locus in G-cells of gastrin-null mice will facilitate investigation of gastrin gene regulatory elements. Isolation of a highly homogeneous population of G-cells permits the elucidation of stimulatory and inhibitory ligands without the confounding presence of other neuroendocrine cells. The use of somatostatin receptor knockout mice demonstrated the plasticity of gastric acid regulatory mechanisms and compensation by upregulation of the galanin pathway which inhibits secretion by enterochromaffin-like cells. The importance of adenosine in regulating somatostatin release was shown using adenosine receptor knockout mice. SUMMARY The importance of gastrointestinal peptides for regulating gastric acid is evident. Ongoing investigations will characterize the mechanisms underlying actions of these agents on gastric acid secretion, particularly with regard to their combinatorial effects and interplay with other acid-regulating pathways.
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Affiliation(s)
- Erik C von Rosenvinge
- Division of Gastroenterology and Hepatology, University of Maryland School of Medicine, Baltimore VA Medical Center, Baltimore, Maryland 21201, USA.
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Abstract
PURPOSE OF REVIEW This review summarizes the last year's literature regarding the regulation and measurement of gastric exocrine and endocrine secretion. RECENT FINDINGS Parietal cells, distributed along much of the length of the oxyntic glands, with highest density in the neck and base, secrete HCl as well as transforming growth factor-alpha, amphiregulin, heparin-binding epidermal growth factor-like growth factor, and sonic hedgehog. Acid facilitates the digestion of protein and absorption of iron, calcium, vitamin B(12) as well as prevents bacterial overgrowth, enteric infection, and possibly food allergy. The major stimulants of acid secretion are gastrin, histamine, and acetylcholine. Ghrelin and orexin also stimulate acid secretion. The main inhibitor of acid secretion is somatostatin. Nitric oxide and dopamine also inhibit acid secretion. Although Helicobacter pylori is associated with duodenal ulcer disease, most patients infected with the organism produce less than normal amount of acid. The cytoskeletal proteins ezrin and moesin participate in parietal cell acid and chief cell pepsinogen secretion, respectively. SUMMARY Despite our vast knowledge, the understanding of the regulation of gastric acid secretion in health and disease is far from complete. A better understanding of the pathways and mechanisms regulating acid secretion should lead to improved management of patients with acid-induced disorders as well as those who secrete too little acid.
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