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Seifi M, Swinny JD. Immunolocalization of AMPA receptor subunits within the enteric nervous system of the mouse colon and the effect of their activation on spontaneous colonic contractions. Neurogastroenterol Motil 2016; 28:705-20. [PMID: 26867789 DOI: 10.1111/nmo.12768] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 12/08/2015] [Indexed: 12/14/2022]
Abstract
BACKGROUND The appropriate expression of specific neurotransmitter receptors within the cellular networks that compose the enteric nervous system (ENS) is central to the regulation of gastrointestinal (GI) functions. While the ENS expression patterns of the neurotransmitter glutamate have been well documented, the localization of its receptors on ENS neurons remains to be fully characterized. We investigated the expression patterns of glutamate receptor AMPA subunits within ENS neurons of the mouse colon and the consequences of their pharmacological activation on spontaneous colonic contractility. METHODS RT-PCR was used to detect individual AMPA receptor (GluR 1-4) subunit expression at the mRNA level in mouse colon tissue. Immunohistochemistry and confocal microscopy was used to localize the expression of the GluR1 and 4 subunits in colon tissue. Brain tissue was used as a positive control. Organ bath preparations were used to determine the effect of AMPA receptors activation on the force and frequency of colonic longitudinal smooth muscle spontaneous contractions. KEY RESULTS GluR1, 3, 4 mRNA was detected in the mouse colon. Immunoreactivity for GluR1 and 4 subunits was detected on the somatic and dendritic surfaces of subpopulations of neurochemically defined ENS neurons. The pharmacological activation of AMPA receptors increased the force but not frequency of spontaneous colonic contractions. CONCLUSIONS & INFERENCES Molecularly distinct AMPA receptor subtypes are differentially expressed within the neural networks of the mouse colon and have a direct role in motility. These data provide the rationale for the development of AMPA-selective ligands for the therapeutic delivery to the GIT in motility disorders.
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Affiliation(s)
- M Seifi
- Institute for Biomedical and Biomolecular Sciences, School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, UK
| | - J D Swinny
- Institute for Biomedical and Biomolecular Sciences, School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, UK
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Ogundele OM, Okunnuga AA, Fabiyi TD, Olajide OJ, Akinrinade ID, Adeniyi PA, Ojo AA. NMDA-R inhibition affects cellular process formation in Tilapia melanocytes; a model for pigmented adrenergic neurons in process formation and retraction. Metab Brain Dis 2014; 29:541-51. [PMID: 24242214 DOI: 10.1007/s11011-013-9447-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 10/22/2013] [Indexed: 12/23/2022]
Abstract
Parkinson's disease has long been described to be a product of dopamine and (or) melanin loss in the substanstia nigra (SN). Although most studies have focused on dopaminergic neurons, it is important to consider the role of pigment cells in the etiology of the disease and to create an in vitro live cell model for studies involving pigmented adrenergic cells of the SN in Parkinsonism. The Melanocytes share specific features with the pigmented adrenergic neurons as both cells are pigmented, contain adrenergic receptors and have cellular processes. Although the melanocyte cellular processes are relatively short and observable only when stimulated appropriately by epinephrine and other factors or molecules. This study employs the manipulation of N-Methyl-D-Aspartate Receptor (NMDA-R), a major receptor in neuronal development, in the process formation pattern of the melanocyte in order to create a suitable model to depict cellular process elongation and shortening in pigmented adrenergic cells. NMDA-R is an important glutamate receptor implicated in neurogenesis, neuronal migration, maturation and cell death, thus we investigated the role of NMDA-R potentiation by glutamate/KCN and its inhibition by ketamine in the behavior of fish scale melanocytes in vitro. This is aimed at establishing the regulatory role of NMDA-R in this cell type (melanocytes isolated form Tilapia) in a similar manner to what is observable in the mammalian neurons. In vitro live cell culture was prepared in modified Ringer's solution following which the cells were treated as follows; Control, Glutamate, Ketamine, Glutamate + Ketamine, KCN + Ketamine and KCN. The culture was maintained for 10 min and the changes were captured in 3D-Time frame at 0, 5 and 10 min for the control and 5, 7 and 10 min for each of the treatment category. Glutamate treatment caused formation of short cellular processes localized directly on the cell body while ketamine treatment (inhibition of NMDA-R) facilitated elongation of secondary cellular processes (highly branched) from primary major processes (Less branched); co-incubation of glutamate and ketamine induced short and highly branched process formation. Cyanide toxicity induced degeneration and reduction of cell size while co-treatment of cyanide and ketamine gave changes similar to that observed in glutamate-ketamine co-incubation. NMDA-R is present in the melanocytes. Activation of the receptor reduced elongation process, while inhibition of the receptor facilitated cell process elongation and branching. This confirms that like pigmented adrenergic cells of the nervous system, this cell contains NMDA-R and this receptor also regulates cell process elongation. The study also showed that inhibition of NMDA-R in melanocytes gave opposite outcomes to the role of the receptor in developing neurons; a function that is protective in adult neurons.
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Affiliation(s)
- Olalekan Michael Ogundele
- Department of Anatomy, College of Medicine and Health Sciences, Afe Babalola University, Ado-Ekiti, Nigeria,
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Zhou Q, Nicholas Verne G. NMDA Receptors and Colitis: Basic Science and Clinical Implications. ACTA ACUST UNITED AC 2008; 10:33-43. [PMID: 20574552 DOI: 10.3727/154296108783994013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
During the last decade, research focusing primarily on alterations in the peripheral and central nervous system has improved our understanding of the pathophysiological mechanisms of chronic visceral pain. These studies have demonstrated significant physiological changes following injury to the viscera in the firing patterns of both primary afferent neurons that transmit nociceptive information from the viscera and in central neurons that process the nociceptive information. A number of receptors, neurotransmitters, cytokines, and second messenger systems in these neurons have been implicated in the enhancement of visceral nociception. N-methyl-d-aspartic acid (NMDA) receptors play an important role in chronic visceral pain and hypersensitivity that is present in the setting of colonic inflammation. NMDA receptors are found in the peripheral nervous system as well as the central terminal of primary afferent neurons and have been shown to play an important role in regulating the release of nociceptive neurotransmitters. Recent work has demonstrated the presence of NMDA receptors in the enteric nervous system. In this article, we will discuss more recent evidence of the role of NMDA receptors in visceral pain associated with colitis.
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Affiliation(s)
- Qiqi Zhou
- Department of Medicine, University of Florida Colleges of Medicine, Gainesville, FL, USA
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Zhou Q, Caudle RM, Moshiree B, Price DD, Verne GN. Phosphorylation of NMDA NR1 subunits in the myenteric plexus during TNBS induced colitis. Neurosci Lett 2006; 406:250-5. [PMID: 16942839 DOI: 10.1016/j.neulet.2006.07.059] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2006] [Accepted: 07/21/2006] [Indexed: 01/18/2023]
Abstract
N-Methyl-d-aspartic acid (NMDA) receptors are known to function in the mediation of pain and have a significant role in the development of hyperalgesia following inflammation. Serine phosphorylation regulation of NMDA receptor function occurs in a variety of conditions. No studies have demonstrated a change in phosphorylation of enteric NMDA receptors following colonic inflammation. We examined the levels of NMDA NR1 phosphorylation in trinitrobenzene sulfonic acid (TNBS) induced colitis in rats and compared it to protein translation and the development of visceral hypersensitivity. We have previously, demonstrated an increase in the C1 cassette of NR1 mRNA expression at 14, 21, and 28 days following TNBS administration. In this study, we examined the NR1 serine phosphorylation at 14 days following TNBS injection. Male Sprague-Dawley rats (200-250 g) were treated with TNBS (20mg per rat) diluted in 50% ethanol (n=3) and vehicle controls of 50% ethanol (n=3). TNBS and vehicle controls were administered with a 24 gauge catheter inserted into the lumen of the rat colon. The animals were sacrificed at 14 days after induction of the colitis and their distal colon was retrieved for two-dimensional (2D) western blot analysis. Serine phosphorylation of the NR1 subunit with C1 cassette appears at 14 days after TNBS injection. In contrast, there was no NR1-C1 expression in the vehicle controls and untreated normal controls. These results suggest a role for colonic-NMDA receptor phosphorylation in the development of neuronal plasticity following colonic inflammation. Phosphorylation of NR1 may partially explain visceral hypersensitivity present during colonic inflammation.
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Affiliation(s)
- QiQi Zhou
- Department of Medicine, University of Florida College of Medicine, Division of Gastroenterology, Hepatology, and Nutrition, Gainesville, FL 32610-0214, USA
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Bennett GD, Moser K, Chaudoin T, Rosenquist TH. The expression of the NR1-subunit of the NMDA receptor during mouse and early chicken development. Reprod Toxicol 2006; 22:536-41. [PMID: 16698234 DOI: 10.1016/j.reprotox.2006.03.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2005] [Revised: 02/22/2006] [Accepted: 03/03/2006] [Indexed: 12/25/2022]
Abstract
It has been suggested that homocysteine-induced defects are mediated by the inhibition of the N-methyl-d-aspartate (NMDA) receptor on neural crest cells. However, the majority of this work has been performed using the chicken embryo model. In an effort to better understand the molecular events involved a murine model of homocysteine-induced defects was sought. However, it has been previously shown that homocysteine failed to induce congenital defects in several strains of mouse. Therefore, in an effort to better understand the difference in the susceptibility between these two species we investigated the ontogeny of the NMDA receptor in the mouse and chicken. To determine the expression of the NMDA receptor we performed Western blot analysis using an antibody to the NR1-subunit of the NMDA receptor in both the chicken and mouse embryos. Further, we used RT-PCR to determine the temporal expression of this subunit in the murine embryos from gestational day 8.5 to 18.5 to confirm our Western blot analysis. Results from these studies demonstrated that the expression of the NMDA receptor was expressed during the early stages of development in the chick embryo but neither the transcript nor the protein was detected in mouse embryos until later in development. These results demonstrate that during the stages of neurulation and/or early heart development the expression of the NR1-subunit of the NMDA receptor was not detected. The expression of this gene increased and was detectable by gestational days 14.5-15.5 and continued to increase in its expression until term. Therefore, these experiments suggest that homocysteine-induced defects may be mediated via the NMDA receptor.
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Affiliation(s)
- Gregory D Bennett
- Department of Genetics Cell Biology and Anatomy, University of Nebraska Medical Center, 985805 UNMC, Omaha, NE 68198-5805, USA.
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Zhou Q, Caudle RM, Price DD, Del Valle-Pinero AY, Verne GN. Selective up-regulation of NMDA-NR1 receptor expression in myenteric plexus after TNBS induced colitis in rats. Mol Pain 2006; 2:3. [PMID: 16417630 PMCID: PMC1402265 DOI: 10.1186/1744-8069-2-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2005] [Accepted: 01/17/2006] [Indexed: 01/11/2023] Open
Abstract
Background N-methyl-D-aspartic acid (NMDA) spinal cord receptors play an important role in the development of hyperalgesia following inflammation. It is unclear, however, if changes in NMDA subunit receptor gene expression in the colonic myenteric plexus are associated with colonic inflammation. We investigated regulation of NMDA-NR1 receptor gene expression in TNBS induced colitis in rats. Male Sprague-Dawley rats (150 g–250 g) were treated with 20 mg trinitrobenzene sulfonic acid (TNBS) diluted in 50% ethanol. The agents were delivered with a 24 gauge catheter inserted into the lumen of the colon. The animals were sacrificed at 2, 7, 14, 21, and 28 days after induction of the colitis, their descending colon was retrieved for reverse transcription-polymerase chain reaction; a subset of animals' distal colon was used for two-dimensional (2-D) western analysis and immunocytochemistry. Results NR1-exon 5 (N1) and NR1-exon 21 (C1) appeared 14, 21 and 28 days after TNBS treatment. NR1 pan mRNA was up-regulated at 14, 21, and 28 days. The NR1-exon 22 (C2) mRNA did not show significant changes. Using 2-D western analysis, untreated control rats were found to express only NR1001 whereas TNBS treated rats expressed NR1001, NR1011, and NR1111. Immunocytochemistry demonstrated NR1-N1 and NR1-C1 to be present in the myenteric plexus of TNBS treated rats. Conclusion These results suggest a role for colonic myenteric plexus NMDA receptors in the development of neuronal plasticity and visceral hypersensitivity in the colon. Up-regulation of NMDA receptor subunits may reflect part of the basis for chronic visceral hypersensitivity in conditions such as post-infectious irritable bowel syndrome.
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Affiliation(s)
- QiQi Zhou
- Department of Medicine, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Robert M Caudle
- Department of Oral and Maxillofacial Surgery, University of Florida College of Dentistry, Gainesville, FL 32610, USA
- Department of Neuroscience, University of Florida College of Dentistry, Gainesville, FL 32610, USA
| | - Donald D Price
- Department of Oral and Maxillofacial Surgery, University of Florida College of Dentistry, Gainesville, FL 32610, USA
- Department of Neuroscience, University of Florida College of Dentistry, Gainesville, FL 32610, USA
| | | | - G Nicholas Verne
- Department of Medicine, University of Florida College of Medicine, Gainesville, FL 32610, USA
- North Florida/South Georgia VA Health System, USA
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Campusano JM, Andrés ME, Magendzo K, Abarca J, Tapia-Arancibia L, Bustos G. Novel Alternative Splicing Predicts a Truncated Isoform of the NMDA Receptor Subunit 1 (NR1) in Embryonic Rat Brain. Neurochem Res 2005; 30:567-76. [PMID: 16076026 DOI: 10.1007/s11064-005-2691-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The expression of mesencephalic brain derived neurotrophic factor (BDNF) has been shown to be regulated by dopaminergic neuronal functioning and glutamate receptors (GluRs). In turn, BDNF participates in the regulation of mesencephalic GluRs' expression. In the present study we analyzed, using semi-quantitative RT-PCR, the effect of BDNF as well as of the GluRs agonists NMDA and trans-(+/-)-1-Amino-(1S,3R)-cyclopentane dicarboxylic acid (t-ACPD), on the expression levels of the NMDA GluR subunit 1 (NR1) mRNA, using rat cultured mesencephalic neurons. In the course of this study, a novel rat mRNA splice variant of NR1 was identified. This new NR1 mRNA isoform is characterized by the insertion of an 82 base pair intron containing an inframe stop codon, thus predicting the expression of a putative truncated protein of 465 amino acids. The RT-PCR and in situ hybridization reveals that the novel NR1 mRNA is expressed in various brain regions of the rat embryo, whereas no expression was detected in the adult rat brain. The modulation of the novel NR1 mRNA isoform by both BDNF and the metabotropic GluR agonist t-ACPD, suggests that the resulting putative NR1 truncated protein may be relevant in the regulatory network of glutamatergic neurotransmission in the developing central nervous system.
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Affiliation(s)
- J M Campusano
- Department of Cell and Molecular Biology, Faculty of Biological Sciences, Laboratory of Biochemical Pharmacology, Catholic University of Chile, Santiago, Chile
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Tsai LH. Function of GABAergic and glutamatergic neurons in the stomach. J Biomed Sci 2005; 12:255-66. [PMID: 15917994 DOI: 10.1007/s11373-005-1357-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2004] [Accepted: 11/18/2004] [Indexed: 11/26/2022] Open
Abstract
Gamma-aminobutyric acid (GABA) and L-glutamic acid (L-Glu) are transmitters of GABAergic and glutamatergic neurons in the enteric interneurons, targeting excitatory or inhibitory GABA receptors or glutamate receptors that modulate gastric motility and mucosal function. GABAergic and glutamatergic neuron immunoreactivity have been found in cholinergic enteric neurons in the stomach. GABA and L-Glu may also subserve hormonal and paracrine signaling. Disruption in gastrointestinal function following perturbation of enteric GABA receptors and glutamate receptors presents potential new target sites for drug development.
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Affiliation(s)
- Li Hsueh Tsai
- Department of Physiology, School of Medicine, Taipei Medical University, Taipei, 11014, Taiwan.
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Tsai LH, Lee YJ, Wu JY. Role of N-methyl-D-aspartate receptors in gastric mucosal blood flow induced by histamine. J Neurosci Res 2004; 77:730-8. [PMID: 15352220 DOI: 10.1002/jnr.20202] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Ionotropic N-methyl-D-aspartate (NMDA) receptor agonists, L-aspartic acid (L-Asp) and NMDA, have been shown to inhibit histamine-stimulated acid secretion, but their effect on gastric mucosal blood flow (GMBF) is largely unknown. The aim of this study was to investigate whether L-Asp and NMDA inhibit histamine-stimulated GMBF and to examine the expression patterns of NMDA receptor subunits NR1, NR2A, and NR2B in rat stomach. Laser Doppler flowmetry was used to measure gastric blood flow in anesthetized rats. The GMBF was assessed during an intravenous infusion of histamine in the presence of tripelennamine. The effects of L-Asp and NMDA on histamine-induced gastric blood flow were examined. In addition, the distribution patterns of NR1-, NR2A-, and NR2B-contaning NMDA receptors in rat stomach were determined immunohistochemically by using specific antibodies against NR1, NR2A, and NR2B. Histamine-induced enhancement of GMBF depended on acid secretion and the activation of H(2)-receptors. Neither L-Asp nor NMDA had an effect on the spontaneous GMBF. However, L-Asp and NMDA reduced the histamine-induced increase in GMBF. DL-2-amino-5-phosphonopentanoic acid (AP-5), an NMDA receptor antagonist; and prazosin, an alpha(1)-receptor antagonist; but not propanolol, a beta(2)-receptor antagonist; or yohimbine, a alpha(2)-receptor antagonist; reversed the inhibitory effect of L-Asp and NMDA on the histamine-induced increase in GMBF. Therefore, L-Asp and NMDA inhibit histamine-induced GMBF via a mechanism involving the activation of NMDA receptors and alpha(1)- adrenoceptors. The fact that NMDA receptor subunits NR1, NR2A, and NR2B were found to be localized in the rat stomach as visualized immunohistochemically with specific antibodies against NR1, NR2A, and NR2B is consistent with this hypothesis.
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Affiliation(s)
- Li Hsueh Tsai
- Department of Physiology, School of Medicine, Taipei Medical University, Taipei, Taiwan.
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