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Ma J, Mistareehi A, Madas J, Kwiat AM, Bendowski K, Nguyen D, Chen J, Li DP, Furness JB, Powley TL, Cheng Z(J. Topographical organization and morphology of substance P (SP)-immunoreactive axons in the whole stomach of mice. J Comp Neurol 2023; 531:188-216. [PMID: 36385363 PMCID: PMC10499116 DOI: 10.1002/cne.25386] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 05/25/2022] [Accepted: 06/21/2022] [Indexed: 11/18/2022]
Abstract
Nociceptive afferents innervate the stomach and send signals centrally to the brain and locally to stomach tissues. Nociceptive afferents can be detected with a variety of different markers. In particular, substance P (SP) is a neuropeptide and is one of the most commonly used markers for nociceptive nerves in the somatic and visceral organs. However, the topographical distribution and morphological structure of SP-immunoreactive (SP-IR) axons and terminals in the whole stomach have not yet been fully determined. In this study, we labeled SP-IR axons and terminals in flat mounts of the ventral and dorsal halves of the stomach of mice. Flat-mount stomachs, including the longitudinal and circular muscular layers and the myenteric ganglionic plexus, were processed with SP primary antibody followed by fluorescent secondary antibody and then scanned using confocal microscopy. We found that (1) SP-IR axons and terminals formed an extensive network of fibers in the muscular layers and within the ganglia of the myenteric plexus of the whole stomach. (2) Many axons that ran in parallel with the long axes of the longitudinal and circular muscles were also immunoreactive for the vesicular acetylcholine transporter (VAChT). (3) SP-IR axons formed very dense terminal varicosities encircling individual neurons in the myenteric plexus; many of these were VAChT immunoreactive. (4) The regional density of SP-IR axons and terminals in the muscle and myenteric plexus varied in the following order from high to low: antrum-pylorus, corpus, fundus, and cardia. (5) In only the longitudinal and circular muscles, the regional density of SP-IR axon innervation from high to low were: antrum-pylorus, corpus, cardia, and fundus. (6) The innervation patterns of SP-IR axons and terminals in the ventral and dorsal stomach were comparable. Collectively, our data provide for the first time a map of the distribution and morphology of SP-IR axons and terminals in the whole stomach with single-cell/axon/synapse resolution. This work will establish an anatomical foundation for functional mapping of the SP-IR axon innervation of the stomach and its pathological remodeling in gastrointestinal diseases.
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Affiliation(s)
- Jichao Ma
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32816
| | - Anas Mistareehi
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32816
| | - Jazune Madas
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32816
| | - Andrew M. Kwiat
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32816
| | - Kohlton Bendowski
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32816
| | - Duyen Nguyen
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32816
| | - Jin Chen
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32816
| | - De-Pei Li
- Center for Precision Medicine, Department of Medicine, School of Medicine, University of Missouri
| | - John B Furness
- Department of Anatomy & Physiology, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
| | - Terry L Powley
- Department of Psychological Sciences, Purdue University, West Lafayette, IN 47906
| | - Zixi (Jack) Cheng
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32816
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Ugan RA, Un H, Kose D, Cadirci E, Bal Tastan T, Yayla M, Halici Z. Can aprepitant used for nausea and vomiting be good gastrointestinal complaints? NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2020; 393:2463-2472. [PMID: 32743741 DOI: 10.1007/s00210-020-01956-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 07/27/2020] [Indexed: 12/14/2022]
Abstract
Aprepitant is a selective SP/NK-1 receptor antagonist and used in postoperative and chemotherapeutics induced emesis and vomiting. The aim of our study is to show aprepitant may have beneficial effects on gastrointestinal complaints in cancer patients undergoing chemotherapeutics by indomethacin-induced gastric ulcer model. A total of 48 rats were fasted 24 h for ulcer experiment. Aprepitant doses of 5, 10, 20, and 40 mg/kg were evaluated for their antiulcer activity. Omeprazole (20 mg/kg) was used as a positive control group. Six hours after 25 mg/kg indomethacin administration, all stomachs were dissected out. After macroscopic analyses, tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), COX-1, and COX-2 mRNA levels and SOD activity, and GSH and MDA levels of stomachs were determined. Histopathological examinations were evaluated. Aprepitant administration exerted 48.14%, 49.62%, 65.92%, and 76.77% ulcer inhibition effects at 5, 10, 20, and 40 mg/kg, respectively. Aprepitant administration decreased oxidative stress and inflammatory parameters in stomach tissues dose dependently. Aprepitant administration increased stomach COX-2 mRNA levels at 20 and 40 mg/kg doses. Although aprepitant appears to be disadvantageous in terms of treating gastric ulcer due to COX enzyme inhibition according to the previous studies, aprepitant has been shown to have ulcer healing effect in our study. When aprepitant is given as an anti-nausea and vomiting drug to cancer patients undergoing chemotherapy, we can argue that it will not be necessary to add a new gastric protective agent as it also shows beneficial effects in gastrointestinal complaints.
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Affiliation(s)
- Rustem Anil Ugan
- Department of Pharmacology, Faculty of Pharmacy, Ataturk University, 25240, Erzurum, Turkey.
| | - Harun Un
- Department of Biochemistry, Faculty of Pharmacy, Agri Ibrahim Cecen University, Agri, Turkey
| | - Duygu Kose
- Department of Pharmacology, Faculty of Medicine, Ataturk University, Erzurum, Turkey
| | - Elif Cadirci
- Department of Pharmacology, Faculty of Medicine, Ataturk University, Erzurum, Turkey
- Clinical Research, Development and Design Application and Research Center, Ataturk University, Erzurum, Turkey
| | - Tugba Bal Tastan
- Department of Histology and Embryology, Faculty of Medicine, Erzincan Binali Yidirim University, Erzincan, Turkey
| | - Muhammed Yayla
- Department of Pharmacology, Faculty of Medicine, Kafkas University, Kars, Turkey
| | - Zekai Halici
- Department of Pharmacology, Faculty of Medicine, Ataturk University, Erzurum, Turkey
- Clinical Research, Development and Design Application and Research Center, Ataturk University, Erzurum, Turkey
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Zhang J, Ma C, Wang R, He C, Li H, Dong S. Endokinin A/B stimulates rat gastric motility through myogenic NK1 receptors located in the fundus. Can J Physiol Pharmacol 2020; 98:691-699. [PMID: 32365302 DOI: 10.1139/cjpp-2019-0522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Endokinin A/B (EKA/B), the common C-terminal decapeptide in endokinins A and B, is a preferred ligand of the NK1 receptor and regulates pain and itch. The study focused on the effects of EKA/B on rat gastric motility in vivo and in vitro. Gastric emptying was measured to evaluate gastric motility in vivo. Intragastric pressure and the contraction of gastric muscle strips were measured to evaluate gastric motility in vitro. Moreover, various neural blocking agents and neurokinin receptor antagonists were applied to explore the mechanisms. TAC4 and TACR1 mRNAs were expressed throughout rat stomach. EKA/B promoted gastric emptying by intraperitoneal injection in vivo. Correspondingly, EKA/B also increased intragastric pressure in vitro. Additionally, EKA/B contracted the gastric muscle strips from the fundus but not from the corpus or antrum. Further studies revealed that the contraction induced by EKA/B on muscle strips from the fundus could be significantly reduced by NK1 receptor antagonist SR140333 but not by NK2 receptor antagonist, NK3 receptor antagonist, or the neural blocking agents used. Our results suggested that EKA/B might stimulate gastric motility mainly through the direct activation of myogenic NK1 receptors located in the fundus.
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Affiliation(s)
- Jing Zhang
- Institute of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tianshui South Road, Lanzhou 730000, People's Republic of China
| | - Chan Ma
- Institute of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tianshui South Road, Lanzhou 730000, People's Republic of China
| | - Ruijia Wang
- Institute of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tianshui South Road, Lanzhou 730000, People's Republic of China
| | - Chunbo He
- Institute of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tianshui South Road, Lanzhou 730000, People's Republic of China
| | - Hailan Li
- Institute of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tianshui South Road, Lanzhou 730000, People's Republic of China
| | - Shouliang Dong
- Institute of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tianshui South Road, Lanzhou 730000, People's Republic of China.,Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Lanzhou University, 222 Tianshui South Road, Lanzhou 730000, People's Republic of China
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Humes DJ, Simpson J, Smith J, Sutton P, Zaitoun A, Bush D, Bennett A, Scholefield JH, Spiller RC. Visceral hypersensitivity in symptomatic diverticular disease and the role of neuropeptides and low grade inflammation. Neurogastroenterol Motil 2012; 24:318-e163. [PMID: 22276853 DOI: 10.1111/j.1365-2982.2011.01863.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND Recurrent abdominal pain is reported by a third of patients with diverticulosis, particularly those with previous episodes of acute diverticulitis. The current understanding of the etiology of this pain is poor. Our aim was to assess visceral sensitivity in patients with diverticular disease and its association with markers of previous inflammation and neuropeptides. METHODS Patients with asymptomatic and symptomatic diverticular disease underwent a flexible sigmoidoscopy and biopsy followed 5-10 days later by visceral sensitivity testing with barostat-mediated rectal distension. Inflammation was assessed by staining of serotonin (5HT) and CD3 positive cells. mRNA levels of tumor necrosis factor alpha (TNF α) and interleukin-6 (IL-6) were quantitated using RT-PCR. Neuropeptide expression was assessed from percentage area staining with substance P (SP) and mRNA levels of the neurokinin 1 & 2 receptors (NK1 & NK2), and galanin 1 receptor (GALR1). KEY RESULTS Thirteen asymptomatic and 12 symptomatic patients were recruited. The symptomatic patients had a lower first reported threshold to pain (28.4 mmHg i.q.r 25.0-36.0) than the asymptomatic patients (47 mmHg i.q.r 36.0-52.5, P < 0.001). Symptomatic patients had a higher median overall pain rating for the stimuli than the asymptomatic patients (P < 0.02). Symptomatic patients had greater median relative expression of NK1 and TNF alpha mRNA compared with asymptomatic patients. There was a significant correlation between barostat VAS pain scores and NK 1 expression (Figure 4, r(2) 0.54, P < 0.02). CONCLUSIONS & INFERENCES Patients with symptomatic diverticular disease exhibit visceral hypersensitivity, and this may be mediated by ongoing low grade inflammation and upregulation of tachykinins.
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Affiliation(s)
- D J Humes
- Nottingham Digestive Disease Centre and Biomedical Research Unit, Nottingham University Hospital NHS Trust, Nottingham, UK.
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Regulation of basal tone, relaxation and contraction of the lower oesophageal sphincter. Relevance to drug discovery for oesophageal disorders. Br J Pharmacol 2007; 153:858-69. [PMID: 17994108 DOI: 10.1038/sj.bjp.0707572] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The lower oesophageal sphincter (LOS) is a specialized region of the oesophageal circular smooth muscle that allows the passage of a swallowed bolus to the stomach and prevents the reflux of gastric contents into the oesophagus. The anatomical arrangement of the LOS includes semicircular clasp fibres adjacent to the lesser gastric curvature and sling fibres following the greater gastric curvature. Such anatomical arrangement together with an asymmetric intrinsic innervation and distinct proportion of neurotransmitters in both regions produces an asymmetric pressure profile. The LOS tone is myogenic in origin and depends on smooth muscle properties that lead to opening of L-type Ca(2+) channels; however it can be modulated by enteric motor neurons, the parasympathetic and sympathetic extrinsic nervous system and several neurohumoral substances. Nitric oxide synthesized by neuronal NOS is the main inhibitory neurotransmitter involved in LOS relaxation. Different putative neurotransmitters have been proposed to play a role together with NO. So far, only ATP or related purines have shown to be co-transmitters with NO. Acetylcholine and tachykinins are involved in the LOS contraction acting through acetylcholine M(3) and tachykinin NK(2) receptors. Nitric oxide can also be involved in the regulation of LOS contraction. The understanding of the mechanisms that originate and modulate LOS tone, relaxation and contraction and the characterization of neurotransmitters and receptors involved in LOS function are important to develop new pharmacological tools to treat primary oesophageal motor disorders and gastro-oesophageal reflux disease.
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Forsgren S, Danielson P, Alfredson H. Vascular NK-1 receptor occurrence in normal and chronic painful Achilles and patellar tendons: studies on chemically unfixed as well as fixed specimens. ACTA ACUST UNITED AC 2005; 126:173-81. [PMID: 15664664 DOI: 10.1016/j.regpep.2004.09.008] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2004] [Revised: 08/31/2004] [Accepted: 09/19/2004] [Indexed: 11/17/2022]
Abstract
It is not known as to whether the Achilles and patellar tendons contain neurokinin-1 (NK-1) receptors. This is a drawback when considering the fact that pain symptoms are frequent in these and as recent studies show that the pain symptoms might be cured via interference with blood vessel function. In the present study, the human Achilles and patellar tendons were examined concerning immunohistochemical expression of the NK-1 receptor. Chemically unfixed and fixed specimens, TRITC and PAP stainings and a battery of NK-1 receptor antibodies, including antibodies against the C-terminus and the N-terminal region, were utilized. NK-1 receptor immunoreaction could be detected in inner parts of the walls of large blood vessels and in the walls of small blood vessels. To some extent, NK-1 immunoreaction was also detectable in small nerve fascicles and in tenocytes. It was found to be of utmost importance to apply both chemically unfixed and fixed specimens. The use of chemically unfixed tissue was found advantageous in order to depict the immunoreactions in the blood vessel walls. The observations represent new findings and are of relevance as substance P (SP) is known to be of importance where neurogenic angiogenesis contributes to diseases and as SP on the whole has profound effects concerning blood vessel regulation.
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Affiliation(s)
- Sture Forsgren
- Department of Integrative Medical Biology, Section for Anatomy, Umeå University, SE-901 87 Umeå, Sweden.
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Persson-Sjögren S, Lejon K, Holmberg D, Forsgren S. Expression of the NK-1 receptor on islet cells and invading immune cells in the non-obese diabetic mouse. J Autoimmun 2005; 24:269-79. [PMID: 15869864 DOI: 10.1016/j.jaut.2005.02.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2004] [Revised: 02/28/2005] [Accepted: 02/28/2005] [Indexed: 11/20/2022]
Abstract
The underlying mechanistic causes of immune cell infiltration in the islets of Langerhans and beta cell failure in the non-obese diabetic (NOD) mouse is still to be completely revealed. Substance P (SP) is a substance known to have pro-inflammatory, endocrine, neuromodulatory and trophic effects, and its preferred receptor, the neurokinin receptor 1 (NK-1 R), is reported to be involved in extravasation of granulocytes and in inflammation and tissue derangement. Therefore, we have investigated the expression of NK-1 R during development of insulitis in the NOD mouse. We show that the magnitude of immunoreactivity scoring NK-1 R expression in the islets was increased in the 12-week-old NOD mouse. Expression of NK-1 R co-localized with expression of glucagon. In line with this expression pattern, we did not detect any effect of SP on glucose-induced insulin release. NK-1 R expression was particularly observed in islet cells in association with the clusters of immune cells. Expression of NK-1 R was also demonstrated in a fraction of the infiltrating B and T lymphocytes, as well as on infiltrating macrophages and dendritic cells. The observations show that the level of NK-1 R expression is increased in 12-week-old NOD mice, being correlated with the occurrence of islet mononuclear infiltration. Our data suggest that SP may act as a chemoattractant, contributing to the pathogenic mononuclear infiltration process in the NOD mouse. On the whole, the observations suggest that SP and the NK-1 R to certain extents are involved in the changes that occur during the development of insulitis in the NOD mouse.
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Affiliation(s)
- Solveig Persson-Sjögren
- Section for Histology and Cell Biology, Department of Integrative Medical Biology, Umeå University, SE-901 87 Umeå, Sweden.
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Jönsson M, Norrgård O, Forsgren S. Substance P and the neurokinin-1 receptor in relation to eosinophilia in ulcerative colitis. Peptides 2005; 26:799-814. [PMID: 15808910 DOI: 10.1016/j.peptides.2004.12.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2004] [Revised: 12/20/2004] [Accepted: 12/20/2004] [Indexed: 11/15/2022]
Abstract
Substance P (SP) has been implicated in the pathophysiology of ulcerative colitis (UC) and it has been suggested that blocking of its effect would be advantageous in this disease. Eosinophils have also been implicated in the pathophysiology of UC. In the present study, specimens from the sigmoid colon of UC patients were investigated by the use of antisera against SP and the neurokinin-1 receptor (NK-1R) and staining for demonstration of eosinophils. The degrees of SP innervation and NK-1R immunoreaction, as well as the levels of eosinophil infiltration, varied between different patients. Interestingly, NK-1R immunoreaction in the epithelium was often seen to be the most marked where there were numerous eosinophils in the underlying mucosa and where the mucosa showed a marked morphologic derangement. The observations suggest that there are marked fluctuations in effects of SP and eosinophils during the disease. The infiltrating eosinophils may be involved in the destruction of the mucosal tissue. Furthermore, for the majority of cases where there is marked derangement of the mucosa, it is apparent that there is an upregulation of the NK-1 receptor in the epithelium in parallel with the infiltration of the eosinophils.
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Affiliation(s)
- Maria Jönsson
- Department of Integrative Medical Biology, Section of Anatomy, Umeå University, SE-90187 Umeå, Sweden.
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Yip L, Leung HCH, Kwok YN. Role of adenosine A1 receptor in the regulation of gastrin release. J Pharmacol Exp Ther 2004; 310:477-87. [PMID: 15044554 DOI: 10.1124/jpet.104.066654] [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: 12/15/2022] Open
Abstract
Adenosine has been demonstrated to inhibit gastric acid secretion. In the rat stomach, this inhibitory effect may be mediated indirectly by the inhibition of gastrin release. Results show that the A(1) receptor agonist N(6)-cyclopentyladenosine (CPA) suppressed immunoreactive gastrin (IRG) release in a concentration-dependent manner. CPA significantly inhibited IRG release at 0.001 microM and maximally inhibited IRG release at 1 microM. At concentrations of 0.001 to 0.1 microM, the A(2A) receptor-selective agonist 2-p-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxamidoadenosine and A(3) receptor-selective agonist 1-deoxy-1-[6-[[(3-iodophenyl)methyl]amino]-9H-purin-9-yl]-N-methyl-beta-d-ribofuranuronamide, had no effect on IRG release, suggesting the involvement of A(1) receptors. In agreement, the A(1) receptor-selective antagonist 8-cyclopentyl-1,3-dipropylxanthine abolished adenosine-induced inhibition of IRG release. Results of immunohistochemistry experiments reveal the presence of A(1) receptor immunoreactivity on mucosal G-cells and D-cells, and the gastric plexi, but not parietal cells, suggesting that adenosine may act directly on G-cells or indirectly on the gastric plexi to modulate IRG release. The structure of the mucosal A(1) receptor was found to be identical to that in the rat brain. Alternative splicing within the coding region of this receptor did not occur. A real-time reverse transcription-polymerase chain reaction assay was developed to measure gastric A(1) receptor gene expression. The highest level of gastric A(1) receptor mRNA was found in the corporeal muscle. However, this level was significantly lower in comparison with the striatum. In conclusion, this study shows that adenosine may suppress IRG release, at least in part, by activating A(1) receptors localized on G-cells and may consequently result in an inhibition of gastric acid secretion.
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Affiliation(s)
- Linda Yip
- Department of Physiology, University of British Columbia, 2146 Health Sciences Mall, Vancouver, BC, Canada V6T 1Z3
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Yip L, Kwok YN. Role of adenosine A2A receptor in the regulation of gastric somatostatin release. J Pharmacol Exp Ther 2004; 309:804-15. [PMID: 14742743 DOI: 10.1124/jpet.103.061986] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Adenosine has been demonstrated to inhibit gastric acid secretion. In the rat stomach, this inhibitory effect may be mediated indirectly by increasing the release of somatostatin-like immunoreactivity (SLI). Results show that adenosine analogs augmented SLI release in the isolated vascularly perfused rat stomach. The rank order of potency of the analogs in stimulating SLI release was 2-p-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxamidoadenosine (CGS 21680) approximately 5'-N-ethylcarboxamidoadenosine > 2-chloroadenosine > R-(-)-N(6)-(2-phenylisopropyl)adenosine >1-deoxy-1-[6-[[(3-iodophenyl)methyl]amino]-9H-purin-9-yl]-N-methyl-beta-d-ribofuranuronamide > N(6)-cyclopentyladenosine approximately N(6)-cyclohexyladenosine > S-(+)-N(6)-(2-phenylisopropyl) adenosine, suggesting the involvement of the A(2A) receptor. In agreement, 4-(2-[7-amino-2-(2-furyl)[1,2,4]triazolo[2,3-a] [1,3,5]triazin-5-ylamino]ethyl)phenol (ZM 241385), an A(2A) receptor antagonist, was shown to abolish the adenosine- and CGS 21680-stimulated SLI release. Immunohistochemical studies reveal the presence of A(2A) receptor immunoreactivity on the gastric plexi and mucosal D-cells, but not on parietal cells and G-cells, suggesting that adenosine may act directly on D-cells or indirectly on the gastric plexi to augment SLI release. The present study also demonstrates that the structure of the mucosal A(2A) receptor is identical to that in the rat brain, and that alternative splicing of this gene does not occur. A real-time reverse transcription-polymerase chain reaction assay has also been established to quantify the levels of A(2A) receptor mRNA. Results show that gastric tissues contained significantly lower levels of A(2A) receptor mRNA compared with the striatum. The lowest level was detected in the mucosa. In conclusion, adenosine may act on A(2A) receptors to augment SLI release and consequently control gastric acid secretion.
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Affiliation(s)
- Linda Yip
- Department of Physiology, University of British Columbia, Vancouver, Canada
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Kuramoto H, Oomori Y, Murabayashi H, Kadowaki M, Karaki SI, Kuwahara A. Localization of neurokinin 1 receptor (NK1R) immunoreactivity in rat esophagus. J Comp Neurol 2004; 478:11-21. [PMID: 15334646 DOI: 10.1002/cne.20169] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The aim of the present immunohistochemical study was to investigate the localization of neurokinin 1 receptor (NK1R) in rat esophagus and examine the relationship between NK1Rs and intrinsic cholinergic, nitrergic, or substance P (SP) neurons. NK1R immunoreactivity (IR) was observed on the nerve cell bodies in the myenteric ganglia throughout the esophagus, but not on striated muscles and smooth muscle cells of the muscularis mucosae. The frequency of occurrence of NK1R neurons was highest in the cervical esophagus and lowest in the lower thoracic esophagus. Considerable immunoreactivity was seen on the nerve cell surfaces and was also present in the cytoplasm of cell somas and in the initial part of the axons, but not in any other nerve fibers or terminals. Dogiel type I-like morphology was observed in some of the NK1R neurons; however, the majority exhibited polymorphic morphology. Double immunolabeling indicated that a majority (77%) of the NK1R neurons were immunoreactive for choline acetyltransferase (ChAT), while a minority (23%) were immunoreactive for nitric oxide synthase (NOS)-IR. Most of the NK1R neurons (92%) were innervated by the SP nerve fibers. Triple immunolabeling indicated that 70% of the NK1R neurons were associated with intrinsic SP nerve fibers (without CGRP-IR), 59% were associated with extrinsic SP nerve fibers (with CGRP-IR), and 35% were associated with both intrinsic and extrinsic SP nerve fibers. These results suggest that SP/tachykinin released from the SP nerve fibers of intrinsic and/or extrinsic origin activates the predominantly intrinsic cholinergic neurons via NK1Rs to influence neuronal transmission or motility in rat esophagus.
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Affiliation(s)
- Hirofumi Kuramoto
- Department of Applied Biology, Kyoto Institute of Technology, Kyoto 606-8585, Japan.
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