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Mori H, Verbeure W, Schol J, Carbone F, Tack J. Gastrointestinal hormones and regulation of gastric emptying. Curr Opin Endocrinol Diabetes Obes 2022; 29:191-199. [PMID: 35081068 DOI: 10.1097/med.0000000000000707] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
PURPOSE OF REVIEW In this review, we evaluate recent findings related to the association between gastrointestinal hormones and regulation of gastric emptying. RECENT FINDINGS Motilin and ghrelin, which act during fasting, promote gastric motility, whereas most of the hormones secreted after a meal inhibit gastric motility. Serotonin has different progastric or antigastric motility effects depending on the receptor subtype. Serotonin receptor agonists have been used clinically to treat dyspepsia symptoms but other hormone receptor agonists or antagonists are still under development. Glucagon-like peptide 1 agonists, which have gastric motility and appetite-suppressing effects are used as a treatment for obesity and diabetes. SUMMARY Gastrointestinal hormones play an important role in the regulation of gastric motility. Various drugs have been developed to treat delayed gastric emptying by targeting gastrointestinal hormones or their receptors but few have been commercialized.
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Affiliation(s)
- Hideki Mori
- Translational Research Center for Gastrointestinal Disorders, KU Leuven, Leuven, Belgium
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Li S, Lei Y, Chen JD. Roles of ATP sensitive potassium channel in modulating gastric tone and accommodation in dogs. Scand J Gastroenterol 2017; 52:515-522. [PMID: 28270043 DOI: 10.1080/00365521.2017.1289238] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE The ATP sensitive potassium (KATP) channel plays an important role in the regulation of resting membrane potential and membrane excitability. The role of the KATP channel in modulating gastric motility is unclear. The aim of this study was to investigate the role and mechanism of the KATP channel in modulating gastric tone and accommodation in dogs. MATERIALS AND METHODS Gastric volume under a constant pressure reflecting gastric tone was measured using a barostat device in dogs equipped with a gastric cannula. Gastric accommodation was evaluated by the difference in gastric volume before and after a liquid meal. The roles of cholinergic and nitrergic pathways in the inhibitory effect of pinacidil (a KATP opener) were assessed. RESULTS 1) Pinacidil dose-dependently decreased gastric tone at a dosage of 30 (p = 0.628), 100 (p = 0.013) and 300 μg kg-1 (p < 0.001). 2) Glibenclamide, a KATP blocker, completely blocked the inhibitory effect of pinacidil on gastric tone. 3) Atropine did not block the inhibitory effect of pinacidil on gastric tone but Nω-Nitro-L-arginine methyl ester markedly attenuated the inhibitory effect of pinacidil (p = 0.004). 4) Glibenclamide significantly reduced gastric accommodation (p < 0.001) while pinacidil had no effects on gastric accommodation. 5) Glibenclamide significantly reduced nitric oxide donor sodium nitroprusside-induced gastric relaxation. CONCLUSIONS These findings indicate that the KATP channel plays an important role in modulating gastric tone and accommodation in dogs. The inhibitory effect of pinacidil on gastric tone was through the nitrergic pathway as well as acting directly on smooth muscle cells.
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Affiliation(s)
- Shiying Li
- a Veterans Research and Education Foundation, VA Medical Center , Oklahoma City , OK , USA.,b Division of Gastroenterology and Hepatology , Johns Hopkins University , Baltimore , MD , USA
| | - Yong Lei
- a Veterans Research and Education Foundation, VA Medical Center , Oklahoma City , OK , USA
| | - Jiande Dz Chen
- a Veterans Research and Education Foundation, VA Medical Center , Oklahoma City , OK , USA.,b Division of Gastroenterology and Hepatology , Johns Hopkins University , Baltimore , MD , USA
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Zádori ZS, Fehér Á, Tóth VE, Al-Khrasani M, Köles L, Sipos S, Del Bello F, Pigini M, Gyires K. Dual Alpha2C/5HT1A Receptor Agonist Allyphenyline Induces Gastroprotection and Inhibits Fundic and Colonic Contractility. Dig Dis Sci 2016; 61:1512-23. [PMID: 26860509 DOI: 10.1007/s10620-015-4026-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Accepted: 12/27/2015] [Indexed: 12/09/2022]
Abstract
BACKGROUND Allyphenyline, a novel α2-adrenoceptor (AR) ligand, has been shown to selectively activate α2C-adrenoceptors (AR) and 5HT1A receptors, but also to behave as a neutral antagonist of α2A-ARs. We exploited this unique pharmacological profile to analyze the role of α2C-ARs and 5HT1A receptors in the regulation of gastric mucosal integrity and gastrointestinal motility. METHODS Gastric injury was induced by acidified ethanol in Wistar rats. Mucosal catalase and superoxide dismutase levels were measured by assay kits. The effect of allyphenyline on electrical field stimulation (EFS)-induced fundic and colonic contractions was determined in C57BL/6 mice. RESULTS Intracerebroventricularly injected allyphenyline (3 and 15 nmol/rat) dose dependently inhibited the development of mucosal damage, which was antagonized by ARC 239 (α2B/C-AR and 5HT1A receptor antagonist), (S)-WAY 100135 (selective 5HT1A receptor antagonist), and JP-1302 (selective α2C-AR antagonist). This protection was accompanied by significant elevation of mucosal catalase and superoxide dismutase levels. Allyphenyline (10(-9)-10(-5) M) also inhibited EFS-induced fundic contractions, which was antagonized by ARC 239 and (S)-WAY 100135, but not by JP-1302. Similar inhibition was observed in the colon; however, in this case only ARC 239 reduced this effect, while neither selective inhibition of α2C-ARs and 5HT1A receptors nor genetic deletion of α2A- and α2B-ARs influenced it. CONCLUSIONS Activation of both central α2C-ARs and 5HT1A receptors contributes to the gastroprotective action of allyphenyline in rats. Its inhibitory effect on fundic contractions is mediated by 5HT1A receptors, but neither α2-ARs nor 5HT1A receptors take part in its inhibitory effect on colonic contractility in mice.
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Affiliation(s)
- Zoltán S Zádori
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4., Budapest, 1089, Hungary
| | - Ágnes Fehér
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4., Budapest, 1089, Hungary
| | - Viktória E Tóth
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4., Budapest, 1089, Hungary
| | - Mahmoud Al-Khrasani
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4., Budapest, 1089, Hungary
| | - László Köles
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4., Budapest, 1089, Hungary
| | - Szabina Sipos
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4., Budapest, 1089, Hungary
| | - Fabio Del Bello
- School of Pharmacy, Medicinal Chemistry Unit, University of Camerino, via S. Agostino 1, 62032, Camerino, Italy
| | - Maria Pigini
- School of Pharmacy, Medicinal Chemistry Unit, University of Camerino, via S. Agostino 1, 62032, Camerino, Italy
| | - Klára Gyires
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4., Budapest, 1089, Hungary.
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Li HF, Liu JF, Zhang K, Feng Y. Expression of serotonin receptors in human lower esophageal sphincter. Exp Ther Med 2014; 9:49-54. [PMID: 25452775 PMCID: PMC4247306 DOI: 10.3892/etm.2014.2050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 10/08/2014] [Indexed: 12/13/2022] Open
Abstract
Serotonin (5-HT) is a neurotransmitter and vasoactive amine that is involved in the regulation of a large number of physiological functions. The wide variety of 5-HT-mediated functions is due to the existence of different classes of serotonergic receptors in the mammalian gastrointestinal tract and nervous system. The aim of this study was to explore the expression of multiple types of 5-HT receptor (5-HT1AR, 5-HT2AR, 5-HT3AR, 5-HT4R, 5-HT5AR, 5-HT6R and 5-HT7R) in sling and clasp fibers from the human lower esophageal sphincter (LES). Muscle strips of sling and clasp fibers from the LES were obtained from patients undergoing esophagogastrectomy, and circular muscle strips from the esophagus and stomach were used as controls. Reverse transcription-polymerase chain reaction (RT-PCR), quantitative PCR and western blotting were used to investigate the expression of the various 5-HT receptor types. Messenger RNA for all seven 5-HT receptor types was identified in the sling and clasp fibers of the LES. At the mRNA level, the expression levels were highest for 5-HT3AR and 5-HT4R, and lowest for 5-HT5AR, 5-HT6R and 5-HT7R. At the protein level, the expression levels were highest for 5-HT3AR and 5-HT4R, followed by 5-HT1AR and 5-HT2AR; 5-HT7R was also detected at a low level. The expression of 5-HT5AR and 5-HT6R proteins was not confirmed. The results indicate that a variety of 5-HT receptor types can be detected in the human LES and probably contribute to LES function.
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Affiliation(s)
- He-Fei Li
- Department of Thoracic Surgery, Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 050011, P.R. China
| | - Jun-Feng Liu
- Department of Thoracic Surgery, Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 050011, P.R. China
| | - Ke Zhang
- Department of Thoracic Surgery, Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 050011, P.R. China
| | - Yong Feng
- Department of Thoracic Surgery, Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 050011, P.R. China
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Janssen P, Verschueren S, Rotondo A, Tack J. Role of Y(2) receptors in the regulation of gastric tone in rats. Am J Physiol Gastrointest Liver Physiol 2012; 302:G732-9. [PMID: 22268097 DOI: 10.1152/ajpgi.00404.2011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We set out to determine the effect of peptide YY(3-36) (PYY(3-36)) on the gastric muscle tone in conscious rats by measuring intragastric pressure (IGP) during intragastric nutrient drink infusion. After an overnight fast, a chronically implanted gastric fistula was connected to a custom-made nutrient drink infusion system and a catheter to measure IGP. IGP was measured before and during the infusion of a nutrient drink (Nutridrink; 0.5 ml/min) until 10 ml was infused. Rats were treated with PYY(3-36) (0, 33, and 100 pmol·kg(-1)·min(-1)) in combination with a subcutaneous injection of the Y(2) receptor antagonists JNJ31020028 (10 mg/kg) or BIIE0246 (2 mg/kg). Experiments were also performed after subdiaphragmatic vagotomy and after pretreatment with 3 ml of nutrient drink (to mimic a fed state). IGP was compared as the average IGP during nutrient infusion, represented as means ± SE and compared using ANOVA. PYY(3-36) dose dependently increased the IGP during nutrient infusion (4.7 ± 0.3, 5.7 ± 0.5 and 7.3 ± 0.7 mmHg; P < 0.01) while JNJ31020028 and BIIE0246 could block this increase [4.4 ± 0.5 (P < 0.001) and 4.8 ± 0.4 (P < 0.05) mmHg, respectively]. Also in vagotomized rats, PYY(3-36) was able to significantly increase the IGP during, an effect attenuated by JNJ31020028. BIIE0246 and JNJ31020028 were not able to decrease the IGP when no PYY(3-36) was administered. PYY(3-36) increased gastric tone through an Y(2) receptor-mediated mechanism that does not involve the vagus nerve. Y(2) receptor antagonists were not able to decrease gastric tone without exogenous administration of PYY(3-36), indicating that Y(2) receptors do not play a crucial role in the determination of gastric tone in physiological conditions.
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Affiliation(s)
- P Janssen
- Translational Research Center for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium
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Lobo SB, Denyer M, Britland S, Javid FA. The involvement of the serotonergic transmission system in neonatal and adult rat ileum contractility varies with age. Pharmacology 2011; 88:225-32. [PMID: 21997518 DOI: 10.1159/000331878] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Accepted: 08/08/2011] [Indexed: 11/19/2022]
Abstract
The relevance of age on serotonergic involvement in the control of alimentary contractility has not been pharmacologically described. Experiments were performed to investigate the effects of acetylcholine, atropine, 5-hydroxytryptamine (5-HT) and its related drugs on intestinal segments taken from the neonatal and adult ileum. 5-HT induced concentration-dependent contractions of ileum irrespective of age; however, these contractions were diminished by pretreatment with atropine only in neonatal tissues. In tissues taken from both the neonatal and adult ileum, methysergide (5-HT(1/2/5-7) receptor antagonist), ritanserin (5-HT(2) receptor antagonist), and RS23597-190/SB204070 (5-HT(4) receptor antagonists) all differentially reduced 5-HT-induced contractions at a concentration <100 μmol/l. At higher concentrations, the contractions were comparable to those in control tissues. Granisetron and ondansetron (5-HT(3) receptor antagonists) significantly reduced contractions induced by 5-HT at concentrations >30 μmol/l in both neonatal and adult ileum. Combined treatments with ritanserin, granisetron, plus RS23597-190 reduced or abolished contraction responses induced in neonatal ileum by 5-HT. SB269970A (5-HT(7) receptor antagonist) and WAY100635 (5-HT(1A) receptor antagonist) failed to influence contractile responses induced by 5-HT or 5-HT receptor agonists. Pretreatments with WAY100635 and SB267790A also had no influence on the contractile responses induced by 5-HT(1A/7) receptor agonist, 5-CT, and 5-HT(1A) receptor agonist, 8-OH-DPAT, which itself failed to induce a measurable response. It is concluded that the 5-HT-induced contractions in segments taken from both the neonatal and adult rat ileum were mediated via 5-HT(2) receptors, 5-HT(3) receptors and 5-HT(4) receptors. However, the effect of atropine on the neonatal rat intestine indicates that the mechanism of serotonergic involvement in ileal contractility is influenced by age.
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The Activation of Peripheral 5-HT1A Receptors Can Inhibit Seminal Vesicle Contraction: An In Vivo Animal Study. Urology 2011; 78:376-9. [DOI: 10.1016/j.urology.2011.04.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 03/26/2011] [Accepted: 04/04/2011] [Indexed: 11/21/2022]
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Janssen P, Vos R, Van Oudenhove L, Tack J. Influence of the 5-HT3 receptor antagonist ondansetron on gastric sensorimotor function and nutrient tolerance in healthy volunteers. Neurogastroenterol Motil 2011; 23:444-9, e175. [PMID: 21199175 DOI: 10.1111/j.1365-2982.2010.01655.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Serotonin is believed to be involved in the regulation of the gastric accommodation reflex in man however which receptor subtype(s) are involved remains to be elucidated. METHODS Eleven healthy subjects (nine men, age 19-30) underwent a gastric barostat and a drinking test after treatment with either placebo or ondansetron (8 mg intravenously). During the barostat protocol an intragastric flaccid bag was stepwise distended (2 mmHg increments 2 min) to determine gastric compliance and sensitivity to distention. Subsequently, the pressure level was set at intra-abdominal pressure +2 mmHg while volume was followed before and after administration of a liquid meal (200 mL; 300 kcal). During the drink test volunteers drank at a rate of 15 mL min(-1) until maximal satiation. Results (mean ± SEM) were compared using t-tests and mixed model analysis. KEY RESULTS Gastric compliance was not significantly altered by ondansetron (51.5 ± 5.6 vs 49.2 ± 5.2 mL mmHg(-1)), neither were the pressure thresholds for first perception or discomfort. Ondansetron treatment did not affect basal gastric tone (173 ± 14 vs 156 ± 12 mL), neither did it affect the amplitude of the meal-induced relaxation (160 ± 52 vs 131 ± 43 mL) or the maximum volume increase after the meal (264 ± 54 mL vs 234 ± 51 mL). During the drinking test the amount of liquid meal ingested at maximum satiation was significantly increased by ondansetron (784 ± 74 vs 907 ± 64 mL, P < 0.05). CONCLUSIONS & INFERENCES These data suggest that 5-HT acting at 5-HT(3) receptors is not involved in the control of gastric sensorimotor function, but contributes to the regulation of hunger and satiation in man.
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Affiliation(s)
- P Janssen
- Division of Gastroenterology, Department of Internal Medicine, University Hospital Gasthuisberg, University of Leuven, Leuven, Belgium
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Janssen P, Van Oudenhove L, Casteels C, Vos R, Verbeke K, Tack J. The effects of acute citalopram dosing on gastric motor function and nutrient tolerance in healthy volunteers. Aliment Pharmacol Ther 2011; 33:395-402. [PMID: 21118281 DOI: 10.1111/j.1365-2036.2010.04522.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND It is unclear whether endogenous serotonin release is involved in the regulation of gastric motility and food intake. AIM To study the effect of acute administration of the selective serotonin reuptake inhibitor citalopram on gastric motor function in man. METHODS Nineteen healthy volunteers underwent a gastric barostat, gastric emptying and/or a drinking test after dosing with either placebo or citalopram (20 mg intravenously). In the barostat protocol, a flaccid bag was introduced in the stomach and inflated at intra-abdominal pressure +2 mmHg, volume was recorded before and after administration of a liquid meal (300 kcal). Gastric emptying for solids and liquids was simultaneously assessed using the ¹⁴C-octanoic acid/¹³C-glycine breath test. During the drink test, volunteers drank at a rate of 15 mL/min until maximal satiation. Citalopram was compared with placebo using t-tests and mixed model analysis. RESULTS Citalopram induced a significant preprandial gastric relaxation (volume increase of 154 ± 55 mL vs. -38 ± 33 mL after placebo dosing; P < 0.05), whereas the postprandial volume increase was significantly decreased after citalopram treatment (F₁₂.₈₀ = 4.78, P < 0.0001; maximum volume increase was 304 ± 40 vs. 201 ± 54 mL after placebo and citalopram treatment respectively). Citalopram enhanced solid (123 ± 17 vs. 77 ± 6 min, P < 0.05) but not liquid emptying (62 ± 6 vs. 57 ± 4 min). Satiation scores during the drink test were lower after citalopram (F₁₉.₁₅₃ = 2.02, P = 0.01; volunteers drank 998 ± 129 vs. 765 ± 79 mL after citalopram and placebo treatment respectively). CONCLUSION The observed effects indicate a role for serotonin in the control of gastric motility and food intake.
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Affiliation(s)
- P Janssen
- Translational Research Center for Gastrointestinal Disorders, University of Leuven, Belgium.
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Geeraerts B, Van Oudenhove L, Boesmans W, Vos R, Vanden Berghe P, Tack J. Influence of acute tryptophan depletion on gastric sensorimotor function in humans. Am J Physiol Gastrointest Liver Physiol 2011; 300:G228-35. [PMID: 20884888 DOI: 10.1152/ajpgi.00020.2010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Peripheral serotonin (5-hydrodytryptamine; 5-HT) is involved in the regulation of gastrointestinal motility and sensation, whereas centrally it plays a role in mood regulation. A dysfunctional serotonergic system may provide a plausible link between functional dyspepsia symptoms and its high psychosocial comorbidity such as anxiety and depression. The aim of this study was to evaluate the effect of decreased 5-HT synthesis by acute tryptophan depletion (ATD) on gastric sensorimotor function and nutrient tolerance, anxiety scores, and gastrointestinal mucosal 5-HT concentrations in healthy volunteers. All subjects were studied under a control condition and during ATD. Gastric sensorimotor function and nutrient tolerance were assessed using a barostat (n = 16, mean age 28.8 ± 1.4 yr) and a satiety drinking test (n = 13, mean age 27.3 ± 1.4 yr). Anxiety during the barostat was evaluated using State-Trait Anxiety Inventory (STAI) questionnaire. 5-HT concentrations were measured in fundic and duodenal mucosal biopsies by means of ELISA and immunohistochemistry. ATD significantly decreased plasma tryptophan levels compared with control in every experiment. ATD did not affect gastric sensitivity and compliance but decreased the sensation of nausea during balloon distension (AUC: 17.4 ± 4.3 vs. 11.4 ± 3.4 mm·mmHg, P = 0.030). ATD enhanced the postprandial volume increase (ANOVA, P < 0.05), but this was not accompanied by augmented nutrient tolerance (848 ± 110 vs. 837 ± 99 ml, nonsignificant). ATD had no effect on STAI state anxiety scores. No evidence was found for an effect on the number of enterochromaffin cells, but ATD reduced 5-HT levels in the duodenal mucosa. ATD alters gastric postprandial motor function and distension-induced nausea. These findings confirm involvement of 5-HT in the control of gastric accommodation and sensitivity.
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Affiliation(s)
- Brecht Geeraerts
- Dept. of Gastroenterology, Univ. Hospital Gasthuisberg, Herestraat 49, B-3000 Leuven, Belgium
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Serotonin pharmacology in the gastrointestinal tract: a review. Naunyn Schmiedebergs Arch Pharmacol 2008; 377:181-203. [PMID: 18398601 DOI: 10.1007/s00210-008-0276-9] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2007] [Accepted: 02/15/2008] [Indexed: 12/17/2022]
Abstract
Serotonin (5-hydroxytryptamine or 5-HT) plays a critical physiological role in the regulation of gastrointestinal (GI) function. 5-HT dysfunction may also be involved in the pathophysiology of a number of functional GI disorders, such as chronic constipation, irritable bowel syndrome and functional dyspepsia. This article describes the role of 5-HT in the enteric nervous system (ENS) of the mammalian GI tract and the receptors with which it interacts. Existing serotonergic therapies that have proven effective in the treatment of GI functional disorders and the potential of drugs currently in development are also highlighted. Advances in our understanding of the physiological and pathophysiological roles of 5-HT in the ENS and the identification of selective receptor ligands bodes well for the future development of more efficacious therapies for patients with functional GI disorders.
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Boeckxstaens GE, Tytgat GN, Wajs E, van Nueten L, de Ridder F, Meulemans A, Tack J. The influence of the novel 5-HT1A agonist R137696 on the proximal stomach function in healthy volunteers. Neurogastroenterol Motil 2006; 18:919-26. [PMID: 16961695 DOI: 10.1111/j.1365-2982.2006.00812.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
As fundic dysaccommodation represents one of the pathophysiological mechanisms underlying functional dyspepsia, gastric relaxant agents may serve as a new treatment of this disorder. Previous studies have suggested the involvement of 5HT1 receptors in the control of gastric tone. Our aim was to study the effect of R137696, a novel 5HT1A agonist, on fundus sensorimotor function in healthy volunteers. The effect of single oral doses (1-2 mg) R137696 was evaluated in a double-blind, placebo-controlled manner on fasting fundic volume, visceral perception, distension-evoked symptoms and fundic compliance in 21 healthy male subjects. R137696 increased the proximal stomach volumes in a dose-dependent manner. Distention-evoked symptoms or distention and discomfort threshold were not altered by R137696. A logistic regression model, characterizing the relationships between the volume and the visual analogue scale score for dyspeptic symptoms (nausea, fullness, discomfort, pain and satiety) as a sigmoidal curve, revealed that R137696 had no effect on distension-induced discomfort, fullness, pain and satiety compared to placebo. R137696 relaxes the gastric fundus in fasting conditions but has no effect on distension-evoked dyspeptic symptoms in healthy volunteers.
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Affiliation(s)
- G E Boeckxstaens
- Division of Gastroenterology & Hepatology, Academic Medical Center, Amsterdam, The Netherlands.
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Kitazawa T, Ukai H, Komori S, Taneike T. Pharmacological characterization of 5-hydroxytryptamine-induced contraction in the chicken gastrointestinal tract. ACTA ACUST UNITED AC 2006; 26:157-68. [PMID: 16553644 DOI: 10.1111/j.1474-8673.2006.00365.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
5-Hydroxytryptamine (5-HT) receptor subtypes involved in 5-HT-induced contraction of the chicken gastrointestinal tract were characterized pharmacologically using subtype-selective agonists and antagonists. The proventriculus (area of stomach adjacent to the oesophagus) and ileum are examined. 5-HT applied cumulatively caused sustained contraction of the proventriculus that was not decreased by tetrodotoxin, atropine or l-nitro-arginine methylester (l-NAME). alpha-Methyl-5-HT showed the same potency as that of 5-HT, indicating the involvement of the 5-HT(2) receptor. (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-amino-propane (DOI), 5-methoxytryptamine and 1-(3-chlorophenyl)piperazine hydrochloride (mCPP) were potent, and 2-methyl-5-HT, 5-carboxamidotryptamine, BW723C86 and 6-chloro-2-(1-piperazinyl)pyrazine hydrochloride (MK212) were moderate, but (+/-)-8-hydroxy-2-dipropylaminotetralin hydrobromide (8-OH-DPAT), [endo-N-8-methyl-8-azabicyclo-(3,2,1)oct-3-yl]-2,3-dihydro-(1-methyl)ethyl-2-oxo-1H-benzimidazol-1-carboxamide (BIMU-8) and cisapride were weak agonists. Correlation of pEC(50) values of these agonists with documented pEC(50) values for 5-HT(2C) receptor was higher than 5-HT(2A) and 5-HT(2B). Cinanserin, ketanserin, methiothepin, methysergide, mianserin, (8-[5-(2,4-dimethoxy-5-(4-trifluoromethylphenylsulphonamido)phenyl-5-oxopentyl)-1,3,8-triazaspiro[4,5]decane-2,4-dione hydrochloride (RS102221), N-(1-methyl-1H-indolyl-5-yl)-N'-(3-methyl-5-isothiazolyl)urea (SB204741), spiperone and N-desmethylclozapine concentration-dependently inhibited the contractile responses to 5-HT. Correlation of pK(b)/pA(2) of antagonists with documented pK(i) for 5-HT(2C) receptor was highest among 5-HT(2) receptor subtypes. In the methysergide- and ketanserin-treated proventriculus, 5-HT, 2-methyl-5-HT and cisapride did not enhance the electrical field stimulation (5 Hz)-induced cholinergic contractions. 5-HT applied non-cumulatively caused transient contraction of ileum, and the responses were partly decreased by atropine or tetrodotoxin. 5-Methoxytryptamine, alpha-methyl-5-HT, 5-carboxamidotryptamine, L692,247 and DOI were potent agonists. However, 2-methyl-5-HT, cisapride, BW723C86, 8-OH-DPAT and 5-nonyloxytryptamine, mCPP and MK212 were less effective. Ketanserin and methysergide decreased the 5-HT-induced ileal contraction, but neither GR113808 nor SB269970 inhibited the responses. In conclusion, 5-HT causes contraction of the proventriculus via 5-HT(2C)-like receptors present on smooth muscle. 5-HT also causes contraction of the ileum, but the underlying mechanisms are complex, involving neural and smooth muscle components, and both 5-HT(1)- and 5-HT(2)-like receptors. Neural 5-HT receptors similar to 5-HT(3)/5-HT(4) receptors were not found in the chicken proventriculus and ileum.
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MESH Headings
- Anesthetics, Local/pharmacology
- Animals
- Atropine/pharmacology
- Chickens/physiology
- Dose-Response Relationship, Drug
- Electric Stimulation
- Ileum/drug effects
- Ileum/innervation
- Ileum/metabolism
- In Vitro Techniques
- Ketanserin/pharmacology
- Male
- Muscarinic Antagonists/pharmacology
- Muscle Contraction/drug effects
- Muscle, Smooth/cytology
- Muscle, Smooth/drug effects
- Proventriculus/drug effects
- Proventriculus/innervation
- Proventriculus/metabolism
- Receptor, Serotonin, 5-HT1D/drug effects
- Receptor, Serotonin, 5-HT1D/metabolism
- Receptor, Serotonin, 5-HT2A/drug effects
- Receptor, Serotonin, 5-HT2A/metabolism
- Receptor, Serotonin, 5-HT2C/drug effects
- Receptor, Serotonin, 5-HT2C/metabolism
- Serotonin
- Serotonin Agents/pharmacology
- Spiro Compounds/pharmacology
- Sulfonamides/pharmacology
- Tetrodotoxin/pharmacology
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Affiliation(s)
- T Kitazawa
- Department of Pharmacology, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan
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14
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Abstract
The past 20 years have seen notable advances in our understanding of the physiology and pharmacology of the emetic reflex leading to the identification of the anti-emetic effects of 5-hydroxytryptamine(3) (5-HT(3)) and neurokinin(1) receptor (NK(1)) antagonists. The introduction of 5-HT(3) and NK(1) receptor antagonists into the clinic has had a major impact in alleviating the nausea and vomiting associated with the treatment of cancer and the sequelae to anaesthesia and surgery (post-operative nausea and vomiting, PONV). Despite these advances there are major gaps in our understanding. Interestingly, one of these is the relatively poor ability to treat nausea. Additional gaps in our knowledge are highlighted to provide a framework within which directions for research can be proposed. Particular attention is drawn to: lacunae in knowledge of some currently used anti-emetics such as the source of dopamine required to initiate emesis; the theoretical assumptions and mechanisms underlying the concept of a "universal anti-emetic"; the variety of receptors at which agonists act to have anti-emetic effects (GABA (B), CB(1), 5-HT(1A), ghrelin, opioid); issues of translation from animals to humans and the relationship between the pathways involved in emesis and certain gastrointestinal disorders such as dyspepsia and gastroesophageal reflux, with the latter being of particular interest as some agents affecting reflux are also anti-emetic. Together, the unmet clinical need to adequately control nausea, possibly by new drugs acting within the brainstem, and the significant gaps in understanding key aspects of the emetic reflex, suggest an important need to focus and re-direct research into the distressing and sometimes life-threatening symptoms of nausea and vomiting.
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Affiliation(s)
- Gareth J Sanger
- Neurology and Gastrointestinal Centre of Excellence in Drug Discovery, GlaxoSmithKline, New Frontiers Science Park, Third Avenue, Harlow, Essex, UK
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15
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Janssen P, Prins NH, Moreaux B, Meulemans AL, Lefebvre RA. Characterization of 5-HT7-receptor-mediated gastric relaxation in conscious dogs. Am J Physiol Gastrointest Liver Physiol 2005; 289:G108-15. [PMID: 15746214 DOI: 10.1152/ajpgi.00012.2005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We aimed to evaluate the gastric relaxant capacity of the 5-HT(1/7)-receptor agonist 5-carboxamidotryptamine (5-CT) in conscious dogs and to clarify the mechanism of action by use of selective antagonists, vagotomy, and in vitro experiments. A barostat enabled us to monitor the intragastric volume in response to different treatments (intravenously administered) before and after supradiaphragmatic vagotomy [results presented as the maximum volume change after treatment (mean; n = 5-11)]. In vitro experiments were performed with isolated muscle strips cut from four different stomach regions of the vagotomized dogs [results were fitted to the operational model of agonism to determine the efficacy parameter tau (n = 5)]. 5-CT (0.5-10 microg/kg) caused a dose-dependent gastric relaxation (29-267 ml) that was completely blocked by the selective 5-HT(7)-receptor antagonist SB-269970 (50 microg/kg). After vagotomy, the relaxation to 10 microg/kg 5-CT was significantly less pronounced (73 vs. 267 ml; P < 0.05) but still blocked by SB-269970, whereas the response to the nitric oxide donor nitroprusside was similar to that before vagotomy (178 vs. 218 ml). In vitro, 5-CT concentration dependently inhibited the PGF(2alpha)-contracted muscle strips before and after vagotomy. Although before and after vagotomy the response in every region was mediated by 5-HT(7) receptors (apparent affinity dissociation constant: SB-269970, 8.2-8.6 vs. 8.3-8.6, respectively), the response after vagotomy was less efficacious (log tau: 1.9 to 0.5 vs. 1.4 to -0.1). The results indicate that the 5-CT-induced proximal stomach relaxation in conscious dogs before and after vagotomy is mediated via 5-HT(7) receptors. The decreased efficacy of 5-CT in vitro after vagotomy is probably related to vagotomy-induced changes in receptor density or coupling efficiency and provides a possible explanation for the decreased in vivo response to 5-CT after vagotomy.
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Affiliation(s)
- Pieter Janssen
- Heymans Institute of Pharmacology, Ghent University, Ghent, Belgium.
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16
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Janssen P, Tack J, Sifrim D, Meulemans AL, Lefebvre RA. Influence of 5-HT1 receptor agonists on feline stomach relaxation. Eur J Pharmacol 2005; 492:259-67. [PMID: 15178373 DOI: 10.1016/j.ejphar.2004.03.054] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2004] [Accepted: 03/30/2004] [Indexed: 10/26/2022]
Abstract
Sumatriptan is known for its stomach relaxing properties in both humans and cats, but the receptor involved has not been characterized. In a barostat study the intragastric volume was monitored in sedated cats at constant pressure. The maximum intragastric volume increase after subcutaneous or intravenous administration of saline or agonists was registered [mean (n=4-5)]. Sumatriptan (0.01-1 mg kg(-1)) induced a dose-dependent intragastric volume increase vs. saline (4-15 vs. 5 ml, respectively) that was sometimes accompanied by retching after 8-10 min. Pre-treatment with nitric oxide-synthase inhibitors and different 5-HT(1) receptor antagonists N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-2-pyridinyl-cyclohexanecarboxamide(WAY-100635), 2-methyl-4-(5-methyl-[1,2,4]oxadiazol-3-yl)-biphenyl-4-carboxylic-acid[4-methoxy-3-(4-methyl-piperazin-1-yl)-phenyl]amide(GR-127935), N-acetyl-5-hydroxytryptophyl-5-hydroxytryptophan-amide(5-HTP-DP) and 1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl]piperazine-HCl(NAN-190) did not affect the sumatriptan-induced effect. Alniditan (5-HT(1A/1D) receptor agonist) and flesinoxan (5-HT(1A) receptor agonist) did not induce significant intragastric volume changes. The 5-HT(1F) receptor agonists 5-hydroxy-3-(1-methylpiperidin-4-yl)-1H-indole(BRL-54443) and (R)-(+)-N-(3-dimethylamino-1,2,3,4-tetrahydro-9H-carbazol-6-yl)-4-fluorobenzamide(LY-344864; 0.003-3 mg kg(-1)) however induced a dose-dependent intragastric volume increase (6-36 and 5-26 ml, respectively), no retching was seen. Our results suggest that stimulation of 5-HT(1F) receptors induces feline stomach relaxation. Whether the sumatriptan-induced gastric relaxation in cats is due to interaction with 5-HT(1F) receptors could not be proven absolutely in view of the lack of selective 5-HT(1F) receptor antagonists.
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Affiliation(s)
- Pieter Janssen
- Center for Gastroenterological Research, University of Leuven, Leuven, Belgium.
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17
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Affiliation(s)
- F De Ponti
- Department of Pharmacology, University of Bologna, Via Irnerio 48, I-40126 Bologna, Italy.
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18
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Janssen P, Prins NH, Peeters PJ, Zuideveld KP, Lefebvre RA. 5-HT7 receptor efficacy distribution throughout the canine stomach. Br J Pharmacol 2004; 143:331-42. [PMID: 15339857 PMCID: PMC1575344 DOI: 10.1038/sj.bjp.0705922] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
This study aimed to determine, quantify and explain regional differences in the relaxant response to the selective 5-HT(1) and 5-HT(7) receptor agonist 5-carboxamidotryptamine (5-CT) throughout the canine stomach. Longitudinal muscle strips from eight gastric corpus regions and six antrum regions were mounted for isotonic measurement. The 5-CT-induced relaxation was examined on a prostaglandin F(2alpha)-induced submaximal response, expressed as percentage of this response and fitted to the operational model of agonism (OMOA). 5-HT(7) receptor messenger RNA (mRNA) expression was compared by means of quantitative PCR. 5-CT inhibited PGF(2alpha)-induced tonic contraction (corpus) and increase of phasic contraction amplitude (antrum). The consistent antagonism produced by the selective 5-HT(7) receptor antagonist SB-269970 (10 nm, pA(2) estimates 8.2-8.9) confirmed that in every region, the inhibition by 5-CT was 5-HT(7) receptor mediated. However, variation in the maximum effect (61-108%) and pEC(50) (6.4-8.6) was observed throughout the different regions. The OMOA explained these differences as differences in the efficacy parameter tau (ratio of receptor density and coupling efficiency; log tau estimates ranging from 0.1 to 2.1). The log tau gradient decreases going from the lesser to the greater curvature. A proportional difference (68%) in the relative expression of 5-HT(7) receptor mRNA between the lesser and the greater curvature indicates that differences in receptor density contribute to the observed functional differences. This study illustrates that 5-HT(7) receptors are present throughout the ventral wall of the canine stomach, but the efficacy (expressed as log tau) is clearly greater close to the lesser curvature. Differences in 5-HT(7) receptor expression at least partially explain the functional differences.
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Affiliation(s)
- Pieter Janssen
- Heymans Institute of Pharmacology, Ghent University, Ghent, Belgium.
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19
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Moro E, Crema F, De Ponti F, Frigo G. Triptans and gastric accommodation: pharmacological and therapeutic aspects. Dig Liver Dis 2004; 36:85-92. [PMID: 14971822 DOI: 10.1016/j.dld.2003.09.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In the past decade, several studies have reported a significant delay of gastric emptying induced by the anti-migraine agent sumatriptan (a 5-hydroxytryptamine (5-HT)1B/D receptor agonist) in healthy human beings. In patients with functional dyspepsia, sumatriptan improves gastric accommodation after food consumption and reduce perception of gastric distension, hence relieving epigastric symptoms. Recent studies have established that impaired accommodation after food consumption is a major patho-physiological mechanism in functional dyspepsia and restoration of accommodation is considered to be a potential therapeutic target. The precise site of action of sumatriptan in humans is at present unknown, although recent studies carried out using a canine model indicate that sumatriptan exerts its action on gastric accommodation through 5-HT1B receptors, since both GR127935 and SB216641 (respectively, non selective 5-HT1B/D and selective 5-HT1B receptor antagonists) fully antagonised the effects of sumatriptan. Gastric relaxation and enhanced accommodation to a distending stimulus seem to be a class effect of triptans, since it occurs not only with sumatriptan, but also with second-generation triptans (rizatriptan and naratriptan), at least in a canine model. In dyspeptic patients, administration of triptans would be able to restore gastric accommodation after a meal and to improve symptoms of early satiety, confirming the therapeutic potential of 5-HT1B/D receptor agonists in functional dyspepsia.
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Affiliation(s)
- E Moro
- Department of Internal Medicine and Therapeutics, University of Pavia, Pavia, Italy.
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