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Kuwahara A, Kuwahara Y, Kato I, Kawaguchi K, Harata D, Asano S, Inui T, Marunaka Y. Xenin-25 induces anion secretion by activating noncholinergic secretomotor neurons in the rat ileum. Am J Physiol Gastrointest Liver Physiol 2019; 316:G785-G796. [PMID: 30978113 DOI: 10.1152/ajpgi.00333.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Xenin-25 is a neurotensin-like peptide that is secreted by enteroendocrine cells in the small intestine. Xenin-8 is reported to augment duodenal anion secretion by activating afferent neural pathways. The intrinsic neuronal circuits mediating the xenin-25-induced anion secretion were characterized using the Ussing-chambered, mucosa-submucosa preparation from the rat ileum. Serosal application of xenin-25 increased the short-circuit current in a concentration-dependent manner. The responses were abolished by the combination of Cl--free and HCO3- -free solutions. The responses were almost completely blocked by TTX (10-6 M) but not by atropine (10-5 M) or hexamethonium (10-4 M). The selective antagonists for neurotensin receptor 1 (NTSR1), neurokinin 1 (NK1), vasoactive intestinal polypeptide (VIP) receptors 1 and 2 (VPAC1 and VPAC2, respectively), and capsaicin, but not 5-hydroxyltryptamine receptors 3 and 4 (5-HT3 and 5-HT4), NTSR2, and A803467, inhibited the responses to xenin-25. The expression of VIP receptors (Vipr) in rat ileum was examined using RT-PCR. The Vipr1 PCR products were detected in the submucosal plexus and mucosa. Immunohistochemical staining showed the colocalization of NTSR1 and NK1 with substance P (SP)- and calbindin-immunoreactive neurons in the submucosal plexus, respectively. In addition, NK1 was colocalized with noncholinergic VIP secretomotor neurons. Based on the results from the present study, xenin-25-induced Cl-/ HCO3- secretion is involved in NTSR1 activation on intrinsic and extrinsic afferent neurons, followed by the release of SP and subsequent activation of NK1 expressed on noncholinergic VIP secretomotor neurons. Finally, the secreted VIP may activate VPAC1 on epithelial cells to induce Cl-/ HCO3- secretion in the rat ileum. Activation of noncholinergic VIP secretomotor neurons by intrinsic primary afferent neurons and extrinsic afferent neurons by postprandially released xenin-25 may account for most of the neurogenic secretory response induced by xenin-25. NEW & NOTEWORTHY This study is the first to investigate the intrinsic neuronal circuit responsible for xenin-25-induced anion secretion in the rat small intestine. We have found that nutrient-stimulated xenin-25 release may activate noncholinergic vasoactive intestinal polypeptide (VIP) secretomotor neurons to promote Cl-/ HCO3- secretion through the activation of VIP receptor 1 on epithelial cells. Moreover, the xenin-25-induced secretory responses are mainly linked with intrinsic primary afferent neurons, which are involved in the activation of neurotensin receptor 1 and neurokinin 1 receptor.
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Affiliation(s)
- Atsukazu Kuwahara
- Research Unit for Epithelial Physiology, Research Organization of Science and Technology, Ritsumeikan University , Kusatsu , Japan.,Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine , Kyoto , Japan.,Research Center for Drug Discovery and Pharmaceutical Development Science, Research Organization of Science and Technology, Ritsumeikan University , Kusatsu , Japan
| | - Yuko Kuwahara
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine , Kyoto , Japan
| | - Ikuo Kato
- Department of Medical Biochemistry, Kobe Pharmaceutical University , Kobe , Japan
| | - Kotoku Kawaguchi
- Department of Molecular Physiology, College of Pharmaceutical Sciences, Ritsumeikan University , Kusatsu , Japan
| | - Daiki Harata
- Department of Molecular Physiology, College of Pharmaceutical Sciences, Ritsumeikan University , Kusatsu , Japan
| | - Shinji Asano
- Department of Molecular Physiology, College of Pharmaceutical Sciences, Ritsumeikan University , Kusatsu , Japan
| | | | - Yoshinori Marunaka
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine , Kyoto , Japan.,Research Center for Drug Discovery and Pharmaceutical Development Science, Research Organization of Science and Technology, Ritsumeikan University , Kusatsu , Japan.,Research Institute for Clinical Physiology, Kyoto Industrial Health Association , Kyoto , Japan
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Giancola F, Torresan F, Repossi R, Bianco F, Latorre R, Ioannou A, Guarino M, Volta U, Clavenzani P, Mazzoni M, Chiocchetti R, Bazzoli F, Travagli RA, Sternini C, De Giorgio R. Downregulation of neuronal vasoactive intestinal polypeptide in Parkinson's disease and chronic constipation. Neurogastroenterol Motil 2017; 29:10.1111/nmo.12995. [PMID: 27891695 PMCID: PMC5393951 DOI: 10.1111/nmo.12995] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 10/21/2016] [Indexed: 02/06/2023]
Abstract
BACKGROUND Chronic constipation (CC) is a common and severe gastrointestinal complaint in Parkinson's disease (PD), but its pathogenesis remains poorly understood. This study evaluated functionally distinct submucosal neurons in relation to colonic motility and anorectal function in PD patients with constipation (PD/CC) vs both CC and controls. METHODS Twenty-nine PD/CC and 10 Rome III-defined CC patients were enrolled. Twenty asymptomatic age-sex matched subjects served as controls. Colonic transit time measurement and conventional anorectal manometry were evaluated in PD/CC and CC patients. Colonoscopy was performed in all three groups. Colonic submucosal whole mounts from PD/CC, CC, and controls were processed for immunohistochemistry with antibodies for vasoactive intestinal polypeptide (VIP) and peripheral choline acetyltransferase, markers for functionally distinct submucosal neurons. The mRNA expression of VIP and its receptors were also assessed. KEY RESULTS Four subgroups of PD/CC patients were identified: delayed colonic transit plus altered anorectal manometry (65%); delayed colonic transit (13%); altered manometric pattern (13%); and no transit and manometric impairment (9%). There were no differences in the number of neurons/ganglion between PD/CC vs CC or vs controls. A reduced number of submucosal neurons containing VIP immunoreactivity was found in PD/CC vs controls (P<.05). VIP, VIPR1, and VIPR2 mRNA expression was significantly reduced in PD/CC vs CC and controls (P<.05). CONCLUSIONS AND INFERENCES Colonic motor and rectal sensory functions are impaired in most PD/CC patients. These abnormalities are associated with a decreased VIP expression in submucosal neurons. Both sensory-motor abnormalities and neurally mediated motor and secretory mechanisms are likely to contribute to PD/CC pathophysiology.
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Affiliation(s)
- Fiorella Giancola
- Department of Medical and Surgical Sciences, University of Bologna, and St. Orsola-Malpighi Hospital, Bologna, Italy
- Department of Veterinary Medical Sciences, University of Bologna, Italy
| | - Francesco Torresan
- Department of Medical and Surgical Sciences, University of Bologna, and St. Orsola-Malpighi Hospital, Bologna, Italy
| | - Roberta Repossi
- Department of Medical and Surgical Sciences, University of Bologna, and St. Orsola-Malpighi Hospital, Bologna, Italy
| | - Francesca Bianco
- Department of Medical and Surgical Sciences, University of Bologna, and St. Orsola-Malpighi Hospital, Bologna, Italy
- Department of Veterinary Medical Sciences, University of Bologna, Italy
| | - Rocco Latorre
- Department of Medical and Surgical Sciences, University of Bologna, and St. Orsola-Malpighi Hospital, Bologna, Italy
| | - Alexandros Ioannou
- Department of Medical and Surgical Sciences, University of Bologna, and St. Orsola-Malpighi Hospital, Bologna, Italy
| | - Maria Guarino
- Neurology Unit, St. Orsola-Malpighi Hospital, Bologna, Italy
| | - Umberto Volta
- Department of Medical and Surgical Sciences, University of Bologna, and St. Orsola-Malpighi Hospital, Bologna, Italy
| | - Paolo Clavenzani
- Department of Veterinary Medical Sciences, University of Bologna, Italy
| | - Maurizio Mazzoni
- Department of Veterinary Medical Sciences, University of Bologna, Italy
| | | | - Franco Bazzoli
- Department of Medical and Surgical Sciences, University of Bologna, and St. Orsola-Malpighi Hospital, Bologna, Italy
| | - R. Alberto Travagli
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, Hershey, PA, USA
| | - Catia Sternini
- CURE Digestive Diseases Research Center, Digestive Diseases Division, Departments of Medicine and Neurobiology, University of California Los Angeles, David Geffen School of Medicine, Los Angeles, CA, USA
| | - Roberto De Giorgio
- Department of Medical and Surgical Sciences, University of Bologna, and St. Orsola-Malpighi Hospital, Bologna, Italy
- Centro Unificato di Ricerca Biomedica Applicata, Bologna, Italy
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Foong JPP, Parry LJ, Gwynne RM, Bornstein JC. 5-HT(1A), SST(1), and SST(2) receptors mediate inhibitory postsynaptic potentials in the submucous plexus of the guinea pig ileum. Am J Physiol Gastrointest Liver Physiol 2010; 298:G384-94. [PMID: 20007849 PMCID: PMC2838515 DOI: 10.1152/ajpgi.00438.2009] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Vasoactive intestinal peptide (VIP) immunoreactive neurons are important secretomotor neurons in the submucous plexus. They are the only submucosal neurons to receive inhibitory inputs and exhibit both noradrenergic and nonadrenergic inhibitory synaptic potentials (IPSPs). The former are mediated by alpha(2)-adrenoceptors, but the receptors mediating the latter have not been identified. We used standard intracellular recording, RT-PCR, and confocal microscopy to test whether 5-HT(1A), SST(1), and/or SST(2) receptors mediate nonadrenergic IPSPs in VIP submucosal neurons in guinea pig ileum in vitro. The specific 5-HT(1A) receptor antagonist WAY 100135 (1 microM) reduced the amplitude of IPSPs, an effect that persisted in the presence of the alpha(2)-adrenoceptor antagonist idazoxan (2 microM), suggesting that 5-HT might mediate a component of the IPSPs. Confocal microscopy revealed that there were many 5-HT-immunoreactive varicosities in close contact with VIP neurons. The specific SSTR(2) antagonist CYN 154806 (100 nM) and a specific SSTR(1) antagonist SRA 880 (3 microM) each reduced the amplitude of nonadrenergic IPSPs and hyperpolarizations evoked by somatostatin. In contrast with the other antagonists, CYN 154806 also reduced the durations of nonadrenergic IPSPs. Effects of WAY 100135 and CYN 154806 were additive. RT-PCR revealed gene transcripts for 5-HT(1A), SST(1), and SST(2) receptors in stripped submucous plexus preparations consistent with the pharmacological data. Although the involvement of other neurotransmitters or receptors cannot be excluded, we conclude that 5-HT(1A), SST(1), and SST(2) receptors mediate nonadrenergic IPSPs in the noncholinergic (VIP) secretomotor neurons. This study thus provides the tools to identify functions of enteric neural pathways that inhibit secretomotor reflexes.
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Affiliation(s)
| | - Laura J. Parry
- 2Zoology, University of Melbourne, Parkville, Victoria, Australia
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Foong JPP, Bornstein JC. mGluR(1) Receptors Contribute to Non-Purinergic Slow Excitatory Transmission to Submucosal VIP Neurons of Guinea-Pig Ileum. Front Neurosci 2009; 3:46. [PMID: 20582273 PMCID: PMC2695390 DOI: 10.3389/neuro.21.001.2009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2009] [Accepted: 05/14/2009] [Indexed: 11/23/2022] Open
Abstract
Vasoactive intestinal peptide (VIP) immunoreactive secretomotor neurons in the submucous plexus are involved in mediating bacterial toxin-induced hypersecretion leading to diarrhoea. VIP neurons become hyperexcitable after the mucosa is exposed to cholera toxin, which suggests that the manipulation of the excitability of these neurons may be therapeutic. This study used standard intracellular recording methods to systematically characterize slow excitatory postsynaptic potentials (EPSPs) evoked in submucosal VIP neurons by different stimulus regimes (1, 3 and 15 pulse 30 Hz stimulation), together with their associated input resistances and pharmacology. All slow EPSPs were associated with a significant increase in input resistance compared to baseline values. Slow EPSPs evoked by a single stimulus were confirmed to be purinergic, however, slow EPSPs evoked by 15 pulse trains were non-purinergic and those evoked by 3 pulse trains were mixed. NK1 or NK3 receptor antagonists did not affect slow EPSPs. The group I mGluR receptor antagonist, PHCCC reduced the amplitude of purinergic and non-purinergic slow EPSPs. Blocking mGluR1 receptors depressed the overall response to 3 and 15 pulse trains, but this effect was inconsistent, while blockade of mGluR5 receptors had no effect on the non-purinergic slow EPSPs. Thus, although other receptors are almost certainly involved, our data indicate that there are at least two pharmacologically distinct types of slow EPSPs in the VIP secretomotor neurons: one mediated by P2Y receptors and the other in part by mGluR1 receptors.
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