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United European Gastroenterology Journal Jul 2021Different peripheral pathways are implicated in the regulation of the food ingestion-digestion cycle. (Review)
Review
BACKGROUND
Different peripheral pathways are implicated in the regulation of the food ingestion-digestion cycle.
METHODS
Narrative review on gastrointestinal mechanisms involved in satiety and hunger signalling.
RESULTS
Combined mechano- and chemoreceptors, peripherally released peptide hormones and neural pathways provide feedback to the brain to determine sensations of hunger (increase energy intake) or satiation (cessation of energy intake) and regulate the human metabolism. The gastric accommodation reflex, which consists of a transient relaxation of the proximal stomach during food intake, has been identified as a major determinant of meal volume, through activation of tension-sensitive gastric mechanoreceptors. Motilin, whose release is the trigger of gastric Phase 3, has been identified as the major determinant of return of hunger after a meal. In addition, the release of several peptide hormones such as glucagon-like peptide 1 (GLP-1), cholecystokinin as well as motilin and ghrelin contributes to gut-brain signalling with relevance to control of hunger and satiety. A number of nutrients, such as bitter tastants, as well as pharmacological agents, such as endocannabinoid receptor antagonists and GLP-1 analogues act on these pathways to influence hunger, satiation and food intake.
CONCLUSION
Gastrointestinal mechanisms such as gastric accommodation and motilin release are key determinants of satiety and hunger.
Topics: Animals; Cholecystokinin; Gastrointestinal Tract; Ghrelin; Glucagon-Like Peptide 1; Humans; Hunger; Motilin; Myoelectric Complex, Migrating; Satiation; Taste
PubMed: 34153172
DOI: 10.1002/ueg2.12097 -
Current Opinion in Endocrinology,... Feb 2019This review examines the hormonal regulation of gastric emptying, a topic of increasing relevance, given the fact that medications that are analogs of some of these... (Review)
Review
PURPOSE OF REVIEW
This review examines the hormonal regulation of gastric emptying, a topic of increasing relevance, given the fact that medications that are analogs of some of these hormones or act as agonists at the hormonal receptors, are used in clinical practice for optimizing metabolic control in the treatment of type 2 diabetes and in obesity.
RECENT FINDINGS
The major effects on gastric emptying result from actions of incretins, particularly gastric inhibitory polypeptide, glucagon-like peptide-1, and peptide tyrosine-tyrosine, the duodenal and pancreatic hormones, motilin, glucagon, and amylin, and the gastric orexigenic hormones, ghrelin and motilin. All of these hormones delay gastric emptying, except for ghrelin and motilin which accelerate gastric emptying. These effects on gastric emptying parallel the effects of the hormones on satiation (by those retarding emptying) and increase appetite by those that accelerate emptying. Indeed, in addition to the effects of these hormones on hypothalamic appetite centers and glycemic control, there is evidence that some of their biological effects are mediated through actions on the stomach, particularly with the glucagon-like peptide-1 analogs or agonists used in treating obesity.
SUMMARY
Effects of gastrointestinal hormones on gastric emptying are increasingly recognized as important mediators of satiation and postprandial glycemic control.
Topics: Appetite; Diabetes Mellitus, Type 2; Gastric Emptying; Gastrointestinal Hormones; Humans; Obesity; Satiation
PubMed: 30418188
DOI: 10.1097/MED.0000000000000448 -
Complementary Therapies in Medicine Jun 2024Acupuncture stands out as a prominent complementary and alternative medicine therapy employed for functional dyspepsia (FD). We conducted a Bayesian meta-analysis to... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Acupuncture stands out as a prominent complementary and alternative medicine therapy employed for functional dyspepsia (FD). We conducted a Bayesian meta-analysis to ascertain both the relative effectiveness and safety of various acupuncture methods in the treatment of functional dyspepsia.
METHODS
We systematically searched eight electronic databases, spanning from their inception to April 2023. The eligibility criteria included randomized controlled trials investigating acupuncture treatments for FD. Study appraisal was conducted using the Cochrane risk of bias tool. Pairwise and network meta-analyses were conducted using RevMan 5.3 and ADDIS V.1.16.6 software. Bayesian network meta-analysis was performed to compare and rank the efficacy of different acupuncture therapies for FD symptoms.
RESULTS
This study found that combining different acupuncture methods or using acupuncture in conjunction with Western medicine is more effective in improving symptoms of functional dyspepsia compared to using Western medicine alone. According to the comprehensive analysis results, notably, the combination of Western medicine and acupuncture exhibited superior efficacy in alleviating early satiation and postprandial fullness symptoms. For ameliorating epigastric pain, acupuncture combined with moxibustion proved to be the most effective treatment, while moxibustion emerged as the optimal choice for addressing burning sensations. Warming needle was identified as the preferred method for promoting motilin levels.
CONCLUSION
The findings of this study demonstrate that acupuncture, both independently and in conjunction with other modalities, emerged as a secure and effective treatment option for patients with functional dyspepsia.
Topics: Humans; Dyspepsia; Acupuncture Therapy; Bayes Theorem; Randomized Controlled Trials as Topic
PubMed: 38761869
DOI: 10.1016/j.ctim.2024.103051 -
Neurogastroenterology and Motility Apr 2019There have been many recent advances in the understanding of various aspects of the physiology of gastric motility and gastric emptying. Earlier studies had discovered... (Review)
Review
There have been many recent advances in the understanding of various aspects of the physiology of gastric motility and gastric emptying. Earlier studies had discovered the remarkable ability of the stomach to regulate the timing and rate of emptying of ingested food constituents and the underlying motor activity. Recent studies have shown that two parallel neural circuits, the gastric inhibitory vagal motor circuit (GIVMC) and the gastric excitatory vagal motor circuit (GEVMC), mediate gastric inhibition and excitation and therefore the rate of gastric emptying. The GIVMC includes preganglionic cholinergic neurons in the DMV and the postganglionic inhibitory neurons in the myenteric plexus that act by releasing nitric oxide, ATP, and peptide VIP. The GEVMC includes distinct gastric excitatory preganglionic cholinergic neurons in the DMV and postganglionic excitatory cholinergic neurons in the myenteric plexus. Smooth muscle is the final target of these circuits. The role of the intramuscular interstitial cells of Cajal in neuromuscular transmission remains debatable. The two motor circuits are differentially regulated by different sets of neurons in the NTS and vagal afferents. In the digestive period, many hormones including cholecystokinin and GLP-1 inhibit gastric emptying via the GIVMC, and in the inter-digestive period, hormones ghrelin and motilin hasten gastric emptying by stimulating the GEVMC. The GIVMC and GEVMC are also connected to anorexigenic and orexigenic neural pathways, respectively. Identification of the control circuits of gastric emptying may provide better delineation of the pathophysiology of abnormal gastric emptying and its relationship to satiety signals and food intake.
Topics: Animals; Enteric Nervous System; Gastric Emptying; Gastrointestinal Motility; Ghrelin; Humans; Motilin; Neurons
PubMed: 30740834
DOI: 10.1111/nmo.13546 -
Frontiers in Endocrinology 2021Motilin, produced in endocrine cells in the mucosa of the upper intestine, is an important regulator of gastrointestinal (GI) motility and mediates the phase III of... (Review)
Review
Motilin, produced in endocrine cells in the mucosa of the upper intestine, is an important regulator of gastrointestinal (GI) motility and mediates the phase III of interdigestive migrating motor complex (MMC) in the stomach of humans, dogs and house musk shrews through the specific motilin receptor (MLN-R). Motilin-induced MMC contributes to the maintenance of normal GI functions and transmits a hunger signal from the stomach to the brain. Motilin has been identified in various mammals, but the physiological roles of motilin in regulating GI motility in these mammals are well not understood due to inconsistencies between studies conducted on different species using a range of experimental conditions. Motilin orthologs have been identified in non-mammalian vertebrates, and the sequence of avian motilin is relatively close to that of mammals, but reptile, amphibian and fish motilins show distinctive different sequences. The MLN-R has also been identified in mammals and non-mammalian vertebrates, and can be divided into two main groups: mammal/bird/reptile/amphibian clade and fish clade. Almost 50 years have passed since discovery of motilin, here we reviewed the structure, distribution, receptor and the GI motility regulatory function of motilin in vertebrates from fish to mammals.
Topics: Animals; Gastrointestinal Motility; Humans; Motilin; Muscle Contraction; Receptors, Gastrointestinal Hormone; Receptors, Neuropeptide
PubMed: 34497583
DOI: 10.3389/fendo.2021.700884 -
Science Advances Mar 2023Motilin is an endogenous peptide hormone almost exclusively expressed in the human gastrointestinal (GI) tract. It activates the motilin receptor (MTLR), a class A G...
Motilin is an endogenous peptide hormone almost exclusively expressed in the human gastrointestinal (GI) tract. It activates the motilin receptor (MTLR), a class A G protein-coupled receptor (GPCR), and stimulates GI motility. To our knowledge, MTLR is the first GPCR reported to be activated by macrolide antibiotics, such as erythromycin. It has attracted extensive attention as a potential drug target for GI disorders. We report two structures of G-coupled human MTLR bound to motilin and erythromycin. Our structures reveal the recognition mechanism of both ligands and explain the specificity of motilin and ghrelin, a related gut peptide hormone, for their respective receptors. These structures also provide the basis for understanding the different recognition modes of erythromycin by MTLR and ribosome. These findings provide a framework for understanding the physiological regulation of MTLR and guiding drug design targeting MTLR for the treatment of GI motility disorders.
Topics: Humans; Motilin; Erythromycin; Receptors, Gastrointestinal Hormone; Receptors, Neuropeptide
PubMed: 36921049
DOI: 10.1126/sciadv.ade9020 -
Frontiers in Pharmacology 2021Although gasotransmitters nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (HS) receive a bad connotation; in low concentrations these play a major governing... (Review)
Review
Although gasotransmitters nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (HS) receive a bad connotation; in low concentrations these play a major governing role in local and systemic blood flow, stomach acid release, smooth muscles relaxations, anti-inflammatory behavior, protective effect and more. Many of these physiological processes are upstream regulated by gut peptides, for instance gastrin, cholecystokinin, secretin, motilin, ghrelin, glucagon-like peptide 1 and 2. The relationship between gasotransmitters and gut hormones is poorly understood. In this review, we discuss the role of NO, CO and HS on gut peptide release and functioning, and whether manipulation by gasotransmitter substrates or specific blockers leads to physiological alterations.
PubMed: 34354597
DOI: 10.3389/fphar.2021.720703 -
Frontiers in Endocrinology 2019The energy balance of vertebrates is regulated by the difference in energy input and energy expenditure. Generally, most vertebrates obtain their energy from nutrients... (Review)
Review
The energy balance of vertebrates is regulated by the difference in energy input and energy expenditure. Generally, most vertebrates obtain their energy from nutrients of foods through the gastrointestinal (GI) tract. Therefore, food intake and following food digestion, including motility of the GI tract, secretion and absorption, are crucial physiological events for energy homeostasis. GI motility changes depending on feeding, and GI motility is divided into fasting (interdigestive) and postprandial (digestive) contraction patterns. GI motility is controlled by contractility of smooth muscles of the GI tract, extrinsic and intrinsic neurons (motor and sensory) and some hormones. In mammals, ghrelin (GHRL) and motilin (MLN) stimulate appetite and GI motility and contribute to the regulation of energy homeostasis. GHRL and MLN are produced in the mucosal layer of the stomach and upper small intestine, respectively. GHRL is a multifunctional peptide and is involved in glucose metabolism, endocrine/exocrine functions and cardiovascular and reproductive functions, in addition to feeding and GI motility in mammals. On the other hand, the action of MLN is restricted and species such as rodentia, including mice and rats, lack MLN peptide and its receptor. From a phylogenetic point of view, GHRL and its receptor GHS-R1a have been identified in various vertebrates, and their structural features and various physiological functions have been revealed. On the other hand, MLN or MLN-like peptide (MLN-LP) and its receptors have been found only in some fish, birds and mammals. Here, we review the actions of GHRL and MLN with a focus on contractility of the GI tract of species from fish to mammals.
PubMed: 31156548
DOI: 10.3389/fendo.2019.00278 -
International Journal of Medical... 2022Grape seed is an important natural bioactive product with various health benefits. Interstitial cells of Cajal (ICCs) are pacemaker cells in the gastrointestinal (GI)...
Grape seed is an important natural bioactive product with various health benefits. Interstitial cells of Cajal (ICCs) are pacemaker cells in the gastrointestinal (GI) tract. The present study investigated the effects of grape seed powder (GSP) on ICC properties and GI motility. GSP depolarized the pacemaker potentials of ICCs in a dose‑dependent manner. Y25130 or SB269970 slightly inhibited GSP‑induced effects. However, Y25130 and SB269970 together completely blocked GSP-induced effects. In the presence of inhibitors of protein kinase C, protein kinase A, or mitogen-activated protein kinase, GSP‑induced ICC depolarization was inhibited. GSP increased the intestinal transit rate in normal mice and in mice with acetic acid-induced GI motility disorder. In addition, the levels of motilin and substance P were elevated after GSP dosing. These results demonstrate that GSP can regulate GI motility, and therefore, it is a potential therapeutic agent for treating GI motility disorders.
Topics: Animals; Gastrointestinal Motility; Intestine, Small; Membrane Potentials; Mice; Patch-Clamp Techniques; Powders; Seeds; Vitis
PubMed: 35693751
DOI: 10.7150/ijms.72529