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Kuwahara Y, Kato I, Inui T, Marunaka Y, Kuwahara A. The effect of Xenin25 on spontaneous circular muscle contractions of rat distal colon in vitro. Physiol Rep 2021; 9:e14752. [PMID: 33600071 PMCID: PMC7891183 DOI: 10.14814/phy2.14752] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 09/19/2020] [Accepted: 09/22/2020] [Indexed: 12/13/2022] Open
Abstract
Xenin25 has a variety of physiological functions in the Gastrointestinal (GI) tract, including ion transport and motility. However, the motility responses in the colon induced by Xenin25 remain poorly understood. Therefore, the effect of Xenin25 on the spontaneous circular muscle contractions of the rat distal colon was investigated using organ bath chambers and immunohistochemistry. Xenin25 induced the inhibition followed by postinhibitory spontaneous contractions with a higher frequency in the rat distal colon. This inhibitory effect of Xenin25 was significantly suppressed by TTX but not by atropine. The inhibitory time (the duration of inhibition) caused by Xenin25 was shortened by the NTSR1 antagonist SR48692, the NK1R antagonist CP96345, the VPAC2 receptor antagonist PG99-465, the nitric oxide-sensitive guanylate-cyclase inhibitor ODQ, and the Ca2+ -dependent K+ channel blocker apamin. The higher frequency of postinhibitory spontaneous contractions induced by Xenin25 was also attenuated by ODQ and apamin. SP-, NOS-, and VIP-immunoreactive neurons were detected in the myenteric plexus (MP) of the rat distal colon. Small subsets of the SP-positive neurons were also Calbindin positive. Most of the VIP-positive neurons were also NOS positive, and small subsets of the NK1R-positive neurons were also VIP positive. Based on the present results, we propose the following mechanism. Xenin25 activates neuronal NTSR1 on the SP neurons of IPANs, and transmitters from the VIP and apamin-sensitive NO neurons synergistically inhibit the spontaneous circular muscle contractions via NK1R. Subsequently, the postinhibitory spontaneous contractions are induced by the offset of apamin-sensitive NO neuron activation via the interstitial cells of Cajal. In addition, Xenin25 also activates the muscular NTSR1 to induce relaxation. Thus, Xenin25 is considered to be an important modulator of post prandial circular muscle contraction of distal colon since the release of Xenin25 from enteroendocrine cells is stimulated by food intake.
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Affiliation(s)
- Yuko Kuwahara
- Department of Molecular cell PhysiologyGraduate School of Medical ScienceKyoto Prefectural University of MedicineKyotoJapan
- Research Unit for Epithelial PhysiologyResearch Center for Drug Discovery and Pharmaceutical Development ScienceResearch Organization of Science and TechnologyRitsumeikan UniversityKusatsuJapan
| | - Ikuo Kato
- Department of Medical BiochemistryKobe Pharmaceutical UniversityKobeJapan
| | | | - Yoshinori Marunaka
- Department of Molecular cell PhysiologyGraduate School of Medical ScienceKyoto Prefectural University of MedicineKyotoJapan
- Research Unit for Epithelial PhysiologyResearch Center for Drug Discovery and Pharmaceutical Development ScienceResearch Organization of Science and TechnologyRitsumeikan UniversityKusatsuJapan
- Research Institute for Clinical PhysiologyKyoto Industrial Health AssociationKyotoJapan
| | - Atsukazu Kuwahara
- Research Unit for Epithelial PhysiologyResearch Center for Drug Discovery and Pharmaceutical Development ScienceResearch Organization of Science and TechnologyRitsumeikan UniversityKusatsuJapan
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Neurotensin receptor 1 facilitates intracellular and transepithelial delivery of macromolecules. Eur J Pharm Biopharm 2017; 119:300-309. [DOI: 10.1016/j.ejpb.2017.06.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 05/02/2017] [Accepted: 06/28/2017] [Indexed: 01/11/2023]
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Romański KW. Importance of the enteric nervous system in the control of the migrating motility complex. Physiol Int 2017; 104:97-129. [PMID: 28665193 DOI: 10.1556/2060.104.2017.2.4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The migrating motility complex (MMC), a cyclical phenomenon, represents rudimentary motility pattern in the gastrointestinal tract. The MMC is observed mostly in the stomach and gut of man and numerous animal species. It contains three or four phases, while its phase III is the most characteristic. The mechanisms controlling the pattern are unclear in part, although the neural control of the MMC seems crucial. The main goal of this article was to discuss the importance of intrinsic innervation of the gastrointestinal tract in MMC initiation, migration, and cessation to emphasize that various MMC-controlling mechanisms act through the enteric nervous system. Two main neural regions, central and peripheral, are able to initiate the MMC. However, central regulation of the MMC may require cooperation with the enteric nervous system. When central mechanisms are not active, the MMC can be initiated peripherally in any region of the small bowel. The enteric nervous system affects the MMC in response to the luminal stimuli which can contribute to the initiation and cessation of the cycle, and it may evoke irregular phasic contractions within the pattern. The hormonal regulators released from the endocrine cells may exert a modulatory effect upon the MMC mostly through the enteric nervous system. Their central action could also be considered. It can be concluded that the enteric nervous system is involved in the great majority of the MMC-controlling mechanisms.
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Affiliation(s)
- K W Romański
- 1 Department of Animal Physiology, Faculty of Veterinary Medicine, Wrocław University of Environmental and Life Sciences , Wrocław, Poland
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Porzionato A, Macchi V, Amagliani A, Castagliuolo I, Parenti A, De Caro R. Neurotensin receptor 1 immunoreactivity in the peripheral ganglia and carotid body. Eur J Histochem 2009; 53:e16. [PMID: 30256869 PMCID: PMC3168236 DOI: 10.4081/ejh.2009.e16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/16/2009] [Indexed: 12/16/2022] Open
Abstract
In the present study we investigated, through immunohistochemistry, the presence and location of neurotensin receptor 1 (NTR1) in the peripheral ganglia and carotid body of 16 humans and 5 rats. In both humans and rats, NTR1 immunostained ganglion cells were found in superior cervical ganglia (57.4±11.6% and 72.4±11.4%, respectively, p<0.05), enteric ganglia (51.9±10.4% and 64.6±6.1%, p<0.05), sensory ganglia (69.2±10.7% and 73.0±13.1%, p>0.05) and parasympathetic ganglia (52.1±14.1% and 59.4±14.0%, p>0.05), supporting a modulatory role for NT in these ganglia. Positivity was also detected in 45.6±9.2% and 50.8±6.8% of human and rat type I glomic cells, respectively, whereas type II cells were negative. Our findings suggest that NT produced by type I cells acts in an autocrine or paracrine way on the same cell type, playing a modulatory role on chemoception.
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Affiliation(s)
- A Porzionato
- Section of Anatomy, Department of Human Anatomy and Physiology
| | - V Macchi
- Section of Anatomy, Department of Human Anatomy and Physiology
| | - A Amagliani
- Section of Anatomy, Department of Human Anatomy and Physiology
| | - I Castagliuolo
- Department of Histology, Microbiology, and Medical Biotechnologies
| | - A Parenti
- Section of Pathologic Anatomy, Department of Medical Diagnostic Sciences and Special Therapies, University of Padova, Italy
| | - R De Caro
- Section of Anatomy, Department of Human Anatomy and Physiology
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Carraway RE, Plona AM. Involvement of neurotensin in cancer growth: evidence, mechanisms and development of diagnostic tools. Peptides 2006; 27:2445-60. [PMID: 16887236 DOI: 10.1016/j.peptides.2006.04.030] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2005] [Accepted: 04/06/2006] [Indexed: 12/22/2022]
Abstract
Focusing on the literature of the past 15 years, we evaluate the evidence that neurotensin and neurotensin receptors participate in cancer growth and we describe possible mechanisms. In addition, we review the progress achieved in the use of neurotensin analogs to image tumors in animals and humans. These exciting advances encourage us to pursue further research and stimulate us to consider novel ideas regarding the multiple inputs to cancer growth that neurotensin might influence.
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Affiliation(s)
- Robert E Carraway
- Department of Physiology, University of Massachusetts Medical School, Worcester, MA 01655, USA.
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Assimakopoulos SF, Vagianos CE, Charonis AS, Alexandris IH, Spiliopoulou I, Thomopoulos KC, Nikolopoulou VN, Scopa CD. Experimental obstructive jaundice alters claudin-4 expression in intestinal mucosa: Effect of bombesin and neurotensin. World J Gastroenterol 2006; 12:3410-5. [PMID: 16733860 PMCID: PMC4087874 DOI: 10.3748/wjg.v12.i21.3410] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the influence of experimental obstructive jaundice and exogenous bombesin (BBS) and neurotensin (NT) administration on the expression of the tight junction (TJ)-protein claudin-4 in intestinal epithelium of rats.
METHODS: Forty male Wistar rats were randomly divided into five groups: I = controls, II = sham operated, III = bile duct ligation (BDL), IV = BDL+BBS (30 μg/kg per d), V = BDL+NT (300 μg/kg per d). At the end of the experiment on d 10, endotoxin was measured in portal and aortic blood. Tissue sections of the terminal ileum were examined histologically and immunohistochemically for evaluation of claudin-4 expression in intestinal epithelium.
RESULTS: Obstructive jaundice led to intestinal barrier failure demonstrated by significant portal and aortic endotoxemia. Claudin-4 expression was significantly increased in the upper third of the villi in jaundiced rats and an upregulation of its lateral distribution was noted. Administration of BBS or NT restored claudin-4 expression to the control state and significantly reduced portal and aortic endotoxemia.
CONCLUSION: Experimental obstructive jaundice increases claudin-4 expression in intestinal epithelium, which may be a key factor contributing to the disruption of the mucosal barrier. Gut regulatory peptides BBS and NT can prevent this alteration and reduce portal and systemic endotoxemia.
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Assimakopoulos SF, Alexandris IH, Scopa CD, Mylonas PG, Thomopoulos KC, Georgiou CD, Nikolopoulou VN, Vagianos CE. Effect of bombesin and neurotensin on gut barrier function in partially hepatectomized rats. World J Gastroenterol 2005; 11:6757-64. [PMID: 16425380 PMCID: PMC4725030 DOI: 10.3748/wjg.v11.i43.6757] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the effect of regulatory peptides bombesin (BBS) and neurotensin (NT) on intestinal barrier function in partially hepatectomized rats.
METHODS: Ninety male Wistar rats were randomly divided into five groups: I (n = 10): controls, II (n = 20): sham operated, III (n = 20): partial hepatectomy 70% (PHx), IV (n = 20): PHx+BBS (30 μg/kg/d), V (n = 20): PHx+NT (300 μg/kg/d). Groups IV and V were treated for 8 days before PHx and 48 h post surgery. At the end of the experiment, on day 10, intestinal barrier function was assessed by measuring endotoxin concentrations in portal and aortic blood. Tissue sections of the terminal ileum were examined histologically and villus density, mucosal thickness, mitotic activity and apoptosis in crypts were assessed. In addition, ileal mucosa was analyzed for DNA and protein content and microbiological analysis was performed in cecal contents. To estimate intestinal oxidative stress, lipid peroxidation was determined on tissue homogenates from terminal ileum.
RESULTS: BBS or NT administration significantly reduced portal and systemic endotoxemia observed 48 h after partial hepatectomy. In hepatectomized rats (group III), a trend towards induction of mucosal atrophy was observed, demonstrated by the reduction of villus density, mucosal thickness, protein content and significant reduction of DNA, while these alterations were reversed by regulatory peptides administration. This trophic effect of BBS and NT was accompanied by induction of mitoses above control levels and a significant reduction of apoptosis in intestinal crypts. Intestinal lipid peroxidation was found significantly lower in PHx group and regulatory peptides exerted an antioxidant action, further decreasing this parameter of oxidative stress. The bacterial population of E. coli and aerobic Gram (+) cocci was increased in cecal content of hepatectomized rats, while this parameter was not affected by the administration of BBS or NT.
CONCLUSION: Gut regulatory peptides BBS and NT improve intestinal barrier function and reduce endotoxemia in experimental partial hepatectomy. This effect is, at least in part, mediated by their trophic, antiapoptotic, mitogenic, and antioxidant effect on the intestinal epithelium. This observation might be of potential value in patients undergoing liver resection.
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Affiliation(s)
- Stelios F Assimakopoulos
- Department of Surgery, University of Patras, Medical School, Rion University Hospital, 26500 Patras, Greece
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Assimakopoulos SF, Scopa CD, Zervoudakis G, Mylonas PG, Georgiou C, Nikolopoulou V, Vagianos CE. Bombesin and neurotensin reduce endotoxemia, intestinal oxidative stress, and apoptosis in experimental obstructive jaundice. Ann Surg 2005; 241:159-67. [PMID: 15622004 PMCID: PMC1356859 DOI: 10.1097/01.sla.0000149306.35717.8b] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To evaluate the effect of bombesin (BBS) and neurotensin (NT) on intestinal histopathology, intestinal oxidative stress, and endotoxemia in experimental obstructive jaundice. SUMMARY BACKGROUND DATA Obstructive jaundice compromises gut barrier function, resulting in endotoxemia. BBS and NT, exerting various biologic actions on gastrointestinal tissues, preserve gut mucosal integrity in cases of injury or atrophy. METHODS Seventy male Wistar rats were randomly divided into 5 groups: I = controls, II = sham operated, III = bile duct ligation (BDL), IV = BDL + BBS (30 microg/kg/d), V = BDL + NT (300 microg/kg/d). By the end of the experiment, on day 10, endotoxin was measured in portal and aortic blood. Tissue sections of the terminal ileum were examined histologically, and villus density, mucosal thickness, mitotic activity and apoptosis in crypts were assessed. In addition, ileal mucosa was analyzed for DNA and protein content. To estimate intestinal oxidant/antioxidant equilibrium, lipid peroxidation, protein oxidation, and thiol redox state (reduced glutathione [GSH], oxidized glutathione [GSSG], total nonprotein mixed disulfides [NPSSR], protein thiols [PSH], and protein disulfides [PSSP]) were determined on tissue homogenates from the terminal ileum. RESULTS BBS or NT administration significantly reduced portal and systemic endotoxemia observed in obstructive jaundice. Both factors reversed obstructive jaundice-induced morphologic features of intestinal atrophy, increasing villus density and mucosal thickness. This effect was accompanied by induction of mitoses and reduction of apoptosis in intestinal crypts. Mucosal DNA and protein content were reduced, although not to significant levels, in BDL animals and restored to control levels after BBS or NT treatment. Moreover, BBS or NT administration protected the intestine in jaundiced rats against oxidative stress, as demonstrated by reduction of intestinal lipid peroxidation, increase of the antioxidant GSH, and decrease of the oxidized forms GSSG and NPSSR, while BBS additionally reduced protein oxidation as well. CONCLUSIONS Administration of BBS or NT in bile duct-ligated rats exerts beneficial effects on intestinal oxidative stress, cell proliferation, apoptosis, and endotoxemia. This observation might be of potential value in patients with extrahepatic cholestasis.
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Assimakopoulos SF, Scopa CD, Charonis A, Spiliopoulou I, Georgiou C, Nikolopoulou V, Vagianos CE. Experimental obstructive jaundice disrupts intestinal mucosal barrier by altering occludin expression: beneficial effect of bombesin and neurotensin. J Am Coll Surg 2004; 198:748-57. [PMID: 15110809 DOI: 10.1016/j.jamcollsurg.2003.12.017] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2003] [Revised: 10/15/2003] [Accepted: 12/10/2003] [Indexed: 12/19/2022]
Abstract
BACKGROUND Little is known of the molecular events leading to increased intestinal permeability in obstructive jaundice. This study was undertaken to investigate the influence of experimental obstructive jaundice on the expression of the tight junction-associated protein occludin in the intestinal epithelium. STUDY DESIGN Seventy male Wistar rats were randomly divided into five groups: I, controls; II, sham-operated; III, bile duct ligation (BDL); IV, BDL+Bombesin (BBS) (30 microg/kg/d); and V, BDL+Neurotensin (NT) (300 microg/kg/d). At the end of the experiment, on day 10, endotoxin was measured in portal and aortic blood. Tissue sections of the terminal ileum were examined histologically and immunohistochemically for evaluation of occludin expression in the intestinal epithelium. Lipid peroxidation and protein oxidation were determined on tissue homogenates from terminal ileum and microbiologic analysis was performed in cecal contents. RESULTS Obstructive jaundice resulted in portal and aortic endotoxemia, which was significantly reduced after BBS or NT administration. In the BDL group, there was total loss of occludin expression in numerous enterocytes mainly at the upper third of the villi, while a gradient of positivity existed from crypt to tip. Occludin expression was restored to control state after treatment with BBS or NT. In addition, both peptides reduced intestinal lipid peroxidation, while BBS reduced protein oxidation as well. CONCLUSIONS Experimental obstructive jaundice induces regional loss of occludin expression in the intestinal epithelium, which may be a key factor contributing to the disruption of the mucosal barrier. Gut regulatory peptides BBS and NT prevent this alteration, leading to lower portal and systemic endotoxemia.
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Zerbib F, Piche T, Charles F, Galmiche JP, Bruley des Varannes S. SR 48692, a specific neurotensin receptor antagonist, has no effect on oesophageal motility in humans. Aliment Pharmacol Ther 2004; 19:931-9. [PMID: 15080855 DOI: 10.1111/j.1365-2036.2004.01909.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND The administration of exogenous neurotensin can reduce the lower oesophageal sphincter pressure, but it is unclear whether this effect is pharmacological or physiological. AIM A specific neurotensin receptor antagonist (SR 48692) was used to assess the effect of endogenous neurotensin on lower oesophageal sphincter function. METHODS Twenty-four healthy male subjects were included in a double-blind, placebo-controlled, randomized, cross-over study designed to determine the effects of two single doses (90 and 300 mg, preceded by a loading dose) of SR 48692 on the resting lower oesophageal sphincter pressure, transient lower oesophageal sphincter relaxations, primary oesophageal peristalsis and oesophageal acid exposure. Oesophageal pH and motility recordings were performed during 1 h of fasting and 3 h post-prandially. Plasma neurotensin-like immunoreactivity release was determined by radioimmunoassay. RESULTS During fasting, the lower oesophageal sphincter pressure, transient lower oesophageal sphincter relaxation rate and reflux episodes were similar with the two doses of SR 48692 and placebo. Meal ingestion induced a rise in plasma neurotensin-like immunoreactivity, a decrease in lower oesophageal sphincter pressure and an increase in both the transient lower oesophageal sphincter relaxation rate and the number of reflux episodes, which were not significantly modified by SR 48692. SR 48692 did not affect oesophageal primary peristalsis. CONCLUSION This study shows that SR 48692, a specific neurotensin 1 receptor antagonist, has no effect on oesophageal motility in humans.
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Affiliation(s)
- F Zerbib
- INSERM U539 and Centre d'Investigation Clinique INSERM, Department of Gastroenterology and Hepatology, University of Nantes, Nantes, France
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Abstract
BACKGROUND & AIMS Release of neurotensin (NT) from intestines is markedly stimulated by ingested fat, and NT may facilitate lipid digestion and absorption through various actions that are not fully understood. Our recent finding that NT stimulates hepatic output of bile acids only when bile delivery to the intestine is maintained has led us to investigate the effects of NT on bile acid absorption in the rat small intestine. METHODS We measured the effects of intravenous infusion of NT (3-10 pmol x kg(-1) x min(-1)) on biliary recovery of (3)H-taurocholate ((3)H-TC) and (3)H-cholate administered into proximal and distal intestines or into isolated intestinal segments in situ in biliary fistula rats. To further understand the underlying mechanisms involved, the effects of NT on intestinal absorption of (3)H-D-glucose, (3)H-leucine, (14)C-antipyrine, and (51)Cr-EDTA were investigated by monitoring the absorption of radioactivity into superior mesenteric venous blood. RESULTS Infusion of NT, at doses that caused near physiologic increases in blood NT levels, increased biliary recovery of (3)H-TC from the jejunum (3.4-fold) and ileum (1.7-fold), but did not enhance absorption of (3)H-cholate. NT also facilitated transcellular uptake of (3)H-glucose and (3)H-leucine and increased paracellular uptake to (51)Cr-EDTA and (3)H-mannitol, but did not alter the absorption rate for (14)C-antipyrine. CONCLUSIONS These results indicate that NT can exert a facilitative effect on intestinal bile acid absorption and return to liver. This effect of NT may involve increases in paracellular absorption and carrier-mediated transport by mechanisms not yet identified.
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Affiliation(s)
- X Gui
- Department of Physiology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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Gui X, Degolier TF, Duke GE, Carraway RE. Neurotensin elevates hepatic bile acid secretion in chickens by a mechanism requiring an intact enterohepatic circulation. Comp Biochem Physiol C Toxicol Pharmacol 2000; 127:61-70. [PMID: 11081413 DOI: 10.1016/s0742-8413(00)00126-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Neurotensin (NT), given intravenously at 10-50 pmol/kg per min to anesthetized female chickens equipped with a bile duct fistula, dose-dependently elevated hepatic bile flow and bile acid output but only when the enterohepatic circulation was maintained by returning the bile to the intestinal lumen. Infusion of NT at 10 and 50 pmol/kg per min increased the average hepatic bile acid output over a 30-min period to 138 +/- 11 and 188 +/- 13% of control, respectively. During infusion of NT, plasma levels of immunoreactive NT (iNT) increased in time from the basal level (14 +/- 1.3 pM) to reach steady state at 30 min. There was a near linear relationship between the dose of NT infused and the increment in plasma iNT. In addition, infusion of NT at 40 pmol/kg min gave a plasma level of iNT (approximately/= 88 pM) which was within the range of those observed during duodenal perfusion with lipid (54-300 pM) and near to that measured in hepatic portal blood from fed animals (52 +/- 5 pM). Perfusion of duodenum with lipid released endogenous NT and increased the rate of hepatic bile flow. When NT antagonist SR48692 was given, bile flow rate decreased to the basal level. These results suggest that intestinal NT, released by lipid, may participate in the regulation of hepatic bile acid output by a mechanism requiring an intact enterohepatic circulation.
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Affiliation(s)
- X Gui
- Department of Physiology, University of Massachusetts Medical School, Worcester, MA 01655-0127, USA
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Brown DR, O'Grady SM. Regulation of ion transport in the porcine intestinal tract by enteric neurotransmitters and hormones. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART A, PHYSIOLOGY 1997; 118:309-17. [PMID: 9366062 DOI: 10.1016/s0300-9629(96)00311-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In the present paper, the mechanisms underlying the neural and hormonal regulation of mucosal ion transport in the pig intestinal tract are reviewed. The active transport of NaCl by isolated sheets of porcine intestinal mucosa is modulated by cholinergic and non-cholinergic neurons of undetermined neurochemical identity that lie in the submucosa. The application of electrical field stimulation to mucosa-submucosa preparations from porcine jejunum, ileum, or colon produces rapid elevations in short-circuit current which are inhibited by tetrodotoxin or omega-conotoxin GVIA, blockers of neuronal Na+ and Ca2+ channels, respectively. In porcine ileum, these elevations in current are mimicked in large part by cholinergic agonists and have been attributed to anion secretion. The majority of classical neurotransmitters and gut peptides that have been examined to date increase active transepithelial anion secretion through interactions with G protein-coupled receptors associated with submucosal neurons or situated on the basolateral membranes of epithelial cells. A small number of neuropeptides interact with neuronal receptors to augment NaCl absorption or decrease anion secretion. Noradrenergic control of intestinal transport differs in the porcine small and large intestines, and displays considerable inter-species variability in its cellular underpinnings. Transport regulation by bombesin-like peptides may be mediated by receptors distributed in both the apical and basolateral membrane domains of epithelial cells in porcine colon. The transport process affected by these peptides may be linked to epithelial growth and differentiation. The pig intestinal tract appears to be a useful biological model for resolving the cellular mechanisms by which gut neurotransmitters and hormones act in regulating transepithelial ion fluxes. Its general relevance to human intestinal function is discussed.
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Affiliation(s)
- D R Brown
- University of Minnesota, Department of Veterinary PathoBiology, St. Paul 55108-6010, USA.
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Atoji Y, Hirasawa Y, Yamamoto Y, Suzuki Y. Distribution of neurotensin-immunoreactive neurons in the digestive tract of the chicken. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 1995; 53:185-94. [PMID: 7560755 DOI: 10.1016/0165-1838(94)00172-g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The origin of the neurotensin-containing nerve fibers in the digestive tract of the chicken has been investigated with the use of colchicine and immunohistochemistry. Neurotensin-immunoreactive nerve fibers were found in the smooth muscle layers from the esophagus to the duodenum. Their density of distribution was very high in the esophagus and crop (maximum mean value: 1315/mm2 of sectional area in the lamina muscularis mucosae of the crop) and decreased progressively to the duodenum. Neurotensin-immunoreactive neuronal cell bodies were observed after colchicine treatment in the submucosal plexuses of the esophagus and crop and in the myenteric plexuses of the esophagus, crop, proventriculus and gizzard, and they extended varicose fibers. The number of neurotensin-immunoreactive cell bodies was high in the myenteric plexus of the gizzard (28.3 +/- 2.7/ganglion) but low in the plexuses of the esophagus, crop and proventriculus. Seven days after cutting the glossopharyngeal nerve and vagus nerve unilaterally, the number and extent of neurotensin-immunostained structures in the smooth muscle layers from the esophagus to the gizzard did not show any significant difference between operated and unoperated sides. These results indicate that in the chicken the great majority of neurotensin-immunoreactive enteric fibers originate in the intramural plexuses of the upper digestive wall and are mainly distributed to smooth muscle cells.
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Affiliation(s)
- Y Atoji
- Laboratory of Veterinary Anatomy, Faculty of Agriculture, Gifu University, Japan
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Miller LA, Cochrane DE, Carraway RE, Feldberg RS. Blockade of mast cell histamine secretion in response to neurotensin by SR 48692, a nonpeptide antagonist of the neurotensin brain receptor. Br J Pharmacol 1995; 114:1466-70. [PMID: 7541694 PMCID: PMC1510300 DOI: 10.1111/j.1476-5381.1995.tb13371.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
1. Pretreatment of rat isolated mast cells with SR 48692, a nonpeptide antagonist of the neurotensin (NT) receptor, prevented histamine secretion in response to NT. 2. This inhibition was rapid in onset (approximately 1 min) and dependent upon the concentration of SR 48692 (IC50 approximately 1-10 nM). 3. SR 48692 (1-1000 nM) did not inhibit histamine secretion elicited by substance P, bradykinin or compound 48/80, or by anti-IgE stimulation of sensitized mast cells. 4. When SR 48692 was injected intradermally (5 pmol in 50 microliters) into anaesthetized rats, 15 min before the intradermal injection of NT, it reduced the effect of NT on vascular permeability. 5. When injected intravenously, SR 48692 attenuated the effects of NT on haematocrit and blood stasis. 6. These results demonstrate that SR 48692 selectively antagonizes the actions of NT on rat isolated mast cells as well as mast cells in vivo. Given the demonstrated specific interaction of SR 48692 with receptors for NT in brain, our results suggest the presence of specific NT receptors on mast cells.
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Affiliation(s)
- L A Miller
- Department of Biology, Tufts University, Medford, MA 02155, USA
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16
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Abstract
Using 125I-labeled neurotensin (NT), chicken liver was found to contain high affinity, G-protein-linked receptors directed specifically towards the bioactive C-terminal portion of NT. Binding was proportional to membrane and optimal at pH 7.5. The apparent Kd (approximately 91 pM) for this single class of binding sites was similar to Kds reported for the high-affinity components of NT binding to mammalian brain and intestinal membranes. However, the binding capacity (Bmax, approximately 2.3 pmol/mg) was 10-100 times higher than values reported for these mammalian tissues. Binding was inhibited by GTP analogues and by treatment with pertussis toxin but not by cholera toxin. Treatments with alkaline solutions, shown to inactivate G-proteins, decreased subsequent binding at pH 7.5. Whereas low concentrations of Mg2+ (optimum, approximately 0.5 mM) enhanced NT binding, concentrations of 5 mM and above were inhibitory. Cross-linking of 125I-labeled NT to liver membranes using glutaraldehyde specifically labeled two substances of approximately 52 and approximately 90 kDa, which could represent different binding proteins or complexes. These data demonstrate the presence in chicken liver of large amounts of high-affinity NT receptor(s) coupled to pertussis toxin-sensitive G-protein(s).
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Affiliation(s)
- S P Mitra
- Physiology Department, University of Massachusetts Medical Center, Worcester 01655, USA
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17
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Abstract
Experiments were performed to relate receptor binding to biologic activity for the contractile effect of neurotensin (NT) in guinea pig ileum. The contractile response was examined on pieces of ileum under 1 g tension in a 5 ml bath of oxygenated Tyrode's at 38 degrees C. NT contracted the longitudinal muscle (ED50, approximately 0.3 nM), the 2-3 g response peaking at 1 min and fading rapidly. In the presence of atropine (1 microM), > or = 50% of the response was blocked and the residual effect gave an ED50 of approximately 1.4 nM. In the presence of atropine and CP-96,345, a substance P receptor antagonist (0.2 microM), no contraction was observed at 20 nM NT. Thus, there were two components to the response, one involving acetylcholine (ED50, 0.3 nM) and one substance P (ED50, 1.4 nM). Using membrane preparations and 125I-labeled NT, specific, high affinity receptors for NT were demonstrated in the muscle and myenteric plexus. Scatchard analyses indicated the presence of two binding sites (Kds: approximately 0.1 nM and approximately 2 nM). Sodium ion and GTP analogs inhibited binding. Binding and biologic activity were similar in regard to dependence on specific groups within NT and sensitivity to metal ions. The high potency of Hg++ was consistent with an involvement of free sulfhydryl group(s) in the binding reaction; this was supported by work with SH-directed agents. The results suggest that two receptor types or configurations may mediate the two components of the contractile effect of NT on guinea pig ileum.
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Affiliation(s)
- R E Carraway
- Department of Physiology, University of Massachusetts Medical Center, Worcester 01655-0127
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18
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De la Fuente M, Garrido JJ, Arahuetes RM, Hernanz A. Stimulation of phagocytic function in mouse macrophages by neurotensin and neuromedin N. J Neuroimmunol 1993; 42:97-104. [PMID: 8380808 DOI: 10.1016/0165-5728(93)90216-l] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The neuropeptides neurotensin and neuromedin N (from 10(-12) M to 10(-9) M) have been shown in this study to stimulate significantly in vitro several steps of the phagocytic process: adherence to substrate, chemotaxis, ingestion of inert particles (latex beads) and production of superoxide anion measured by nitroblue tetrazolium reduction in resting peritoneal macrophages from BALB/c mice. A dose-response relationship was observed, with a maximal stimulation of the phagocytic process at 10(-11) M. The two neuropeptides induced no change of intracellular cyclic AMP in murine macrophages. Moreover, adherence and chemotaxis decreased significantly in the presence of EGTA (1 mM), a chelator of extracellular Ca2+, or ryanodine (0.5 mM), a blocker of a Ca(2+)-gated channel from the endoplasmic reticulum, in both controls and samples with the addition of neurotensin or neuromedin N. These results suggest that there is no relation between the cAMP messenger system and the phagocytic process stimulation in murine peritoneal macrophages by neurotensin or neuromedin N. In addition, the results observed with EGTA and ryanodine could indicate that these two neuropeptides produce their effects through an increase of intracellular Ca2+ concentration.
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Affiliation(s)
- M De la Fuente
- Departamento de Fisiología Animal, Facultad de C. Biológicas, Universidad Complutense, Madrid, Spain
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19
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Carraway RE, Mitra SP, Honeyman TW. Effects of GTP analogs and metal ions on the binding of neurotensin to porcine brain membranes. Peptides 1993; 14:37-45. [PMID: 8382811 DOI: 10.1016/0196-9781(93)90008-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Using 125I-labeled neurotensin (NT), porcine brain membranes were found to contain two types of high-affinity receptors, one class (approximately 1/3 of total) with an apparent Kd of 0.12 nM and another with an apparent Kd of 1.4 nM. Nonhydrolyzable analogs of GTP inhibited NT binding in a dose-dependent manner. In the presence of 60 microM guanosine 5'-(3-thio) 5'-(beta, gamma-imino) triphosphate. NT binding was decreased by 35% with an associated decrease in the number of binding sites and little change in the Kd. Cross-linking of 125I-labeled NT to brain membranes using disuccinimidyl suberate was found to specifically label two substances of approximately 120 kDa and approximately 160 kDa, which could represent different binding proteins or complexes. For a series of NT analogs, there was close agreement between the IC50 in the binding assay and the ED50 in a bioassay based on ability to contract the guinea pig ileum. In addition, metal ions inhibited NT binding and the contractile action of NT with the same order of potency (Hg++ > Zn++ > Cu++ > Mn++ > Mg++ > Li++). There was a linear relationship between the standard reduction potential for these ions and the logarithm of the IC50 in the binding assay. The results suggest that porcine brain contains high-affinity, G-protein-linked receptors for NT, the functioning of which depends upon group(s), perhaps sulfhydryl(s), which can interact strongly with certain heavy metal ions.
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Affiliation(s)
- R E Carraway
- Department of Physiology, University of Massachusetts Medical Center, Worcester 01655
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20
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Abstract
We have previously characterized the neurotensin receptors on the circular smooth muscle (CM) of the canine small intestine (1). In the present studies, using radioligand binding technique, neurotensin receptors were localized on the membranes from deep muscular (DMP) and the submucous plexus while no binding was observed on either the longitudinal smooth muscle or myenteric plexus membranes. The high affinity binding sites (Kd 0.1-0.2 nM) on DMP membranes were similar to those on CM; the low affinity component was of much lower affinity (Kd approximately 40 nM). DMP had 4-6 times higher density of binding sites than the CM. The recognition properties of DMP receptors were similar to those on the CM and reduced sulfhydryl groups were required for the binding activity. The action of neurotensin on the contractility of the canine small intestine, therefore, appears to be through a direct action on the circular smooth muscle and through the prejunctional action on the DMP neurons through distinct receptors. Thiol groups in the neurotensin receptors may be important for the receptor function.
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Affiliation(s)
- S Ahmad
- Department of Biomedical Sciences, McMaster University Health Science Centre, Hamilton, Ontario, Canada
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