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Grundy L, Wyndaele JJ, Hashitani H, Vahabi B, Wein A, Abrams P, Chakrabarty B, Fry CH. How does the lower urinary tract contribute to bladder sensation? ICI-RS 2023. Neurourol Urodyn 2023. [PMID: 37902296 DOI: 10.1002/nau.25316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Accepted: 10/17/2023] [Indexed: 10/31/2023]
Abstract
AIM Bladder sensation is critical for coordinating voluntary micturition to maintain healthy bladder function. Sensations are initiated by the activation of sensory afferents that innervate throughout the bladder wall. However, the physiological complexity that underlies the initiation of bladder sensory signaling in health and disease remains poorly understood. This review summarises the latest knowledge of the mechanisms underlying the generation of bladder sensation and identifies key areas for future research. METHODS Experts in bladder sensory signaling reviewed the literature on how the lower urinary tract contributes to bladder sensation and identified key research areas for discussion at the 10th International Consultation on Incontinence-Research Society. RESULTS The importance of bladder sensory signals in maintaining healthy bladder function is well established. However, better therapeutic management of bladder disorders with exaggerated bladder sensation, including overactive bladder syndrome (OAB) and interstitial cystitis/bladder pain syndrome (IC/BPS) is limited by a lack of knowledge in a number of key research areas including; the contribution of different nerves (pudendal, pelvic, hypogastric) to filling sensations in health and disease; the relative contribution of stretch sensitive (muscular) and stretch-insensitive (mucosal) afferents to bladder sensation in health and disease; the direct and indirect contributions of the muscularis mucosae to bladder contraction and sensation; and the impact of manipulating urothelial release factors on bladder sensation. CONCLUSION Disturbances in bladder sensory signaling can have severe consequences for bladder sensation and function including the development of OAB and IC/BPS. Advancing therapeutic treatments for OAB and IC/BPS requires a deeper understanding of the mechanisms underlying the generation of bladder sensation, and key areas for future research have been identified.
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Affiliation(s)
- Luke Grundy
- Neurourology Research Group, Flinders Health and Medical Research Institute, Flinders University, South Australia, Australia
| | | | - Hikaru Hashitani
- Department of Cell Physiology, Nagoya City University, Nagoya, Japan
| | - Bahareh Vahabi
- School of Applied Sciences, University of the West of England, Bristol, UK
| | - Alan Wein
- Perelman School of Medicine, Penn Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Desai Sethi Institute of Urology, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Paul Abrams
- Bristol Urological Institute, Southmead Hospital Bristol, Bristol, UK
| | - Basu Chakrabarty
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, UK
| | - Christopher H Fry
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, UK
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2
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De Jonge B, Pardon B, Goossens E, Van Immerseel F, Vereecke N, Pas ML, Callens J, Caliskan N, Roels S, Chiers K. Hemorrhagic bowel syndrome in dairy cattle: Gross, histological, and microbiological characterization. Vet Pathol 2023; 60:235-244. [PMID: 36601786 DOI: 10.1177/03009858221143402] [Citation(s) in RCA: 1] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Hemorrhagic bowel syndrome (HBS) is a sporadic and fatal disease of predominantly lactating dairy cattle, characterized by segmental hemorrhage and luminal clot formation in the small intestine. Although, Clostridium perfringens and Aspergillus fumigatus have been associated with HBS, the pathogenesis and cause are currently unknown. In this study, 18 naturally occurring cases of HBS (7 necropsied immediately following euthanasia, 11 with 12-48 hour postmortem intervals) were investigated to characterize the pathology and the intestinal microbiome. Hemorrhagic bowel syndrome was characterized by a single small-intestinal, intramucosal hematoma with dissection of the lamina muscularis mucosae. In most cases necropsied immediately after euthanasia (4/7), the intestinal mucosa proximal to the hematoma contained 9 to 14, dispersed, solitary or clustered, erosions or lacerations measuring 4 to 45 mm. In 77% (37/48) of these mucosal lesions, microscopic splitting of the lamina muscularis mucosae comparable to the hematoma was present. These findings suggest the intramucosal hematoma to originate from small mucosal erosions through dissecting hemorrhage within the lamina muscularis mucosae. No invasive fungal growth was observed in any tissue. Bacteriological cultivation and nanopore sequencing showed a polymicrobial population at the hematoma and unaffected intestine, with mostly mild presence of C perfringens at selective culture. Gross and microscopic lesions, as well as the culture and sequencing results, were not in support of involvement of C perfringens or A fumigatus in the pathogenesis of HBS.
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Affiliation(s)
| | | | | | | | - Nick Vereecke
- Ghent University, Merelbeke, Belgium.,PathoSense BV, Lier, Belgium
| | | | | | | | - Stefan Roels
- Animal Health Service Flanders, Torhout, Belgium
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3
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Mihai IM, Olteanu GE, Herman D, Anderco D, Iacob M, Nataras B, Cumpanas AA, Bardan R, Dema A. Analysis of Tumor Depth Invasion With Anti-Smoothelin Antibody in Equivocal Transurethral Resection of Urinary Bladder Tumor Surgical Specimens. Int J Surg Pathol 2020; 29:54-63. [PMID: 33090031 DOI: 10.1177/1066896920967762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE To examine the expression and value of the smoothelin marker in control cases, to standardize the working method, and to analyze its application in pathologic staging process of problematic transurethral resection of bladder tumor (TURBT) cases. MATERIAL AND METHODS Immunohistochemical (IHC) staining was performed on tumor-free bladder wall sections, tumor-free large bowel sections, TURBTs with unequivocal tumor stage, and TURBTs with equivocal stage. The IHC staining of muscularis mucosa (MM), muscularis propria (MP), and blood vessels was evaluated semiquantitatively. RESULTS Smoothelin IHC staining pattern ranged from negative (30% to 67% cases) to 2+ (0% to 15% cases) in MM and from 1+ (10% to 50% cases) to 3+ (9% to 48% cases) in MP. When compared on the same slide, the smoothelin expression of MP showed a stronger staining intensity than the one of the MM in all the analyzed cases. Blood vessel muscle cells stained in a constant intensity as the MM (r = 0.9808; r = 0.9604). Smoothelin determined restaging of 33% of the problematic TURBT cases. CONCLUSION Smoothelin is an IHC marker that shows differential staining between coexistent MM and MP; however, variations in staining intensity and pattern may occur, aspects that can be influenced by different technique variables. We recommend using this marker as a diagnostic tool in problematic TURBT cases only when there is sufficient experience in control cases with this antibody.
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Affiliation(s)
- Ioana Maria Mihai
- Department of Microscopic Morphology - Pathology, "Victor Babeș" University of Medicine and Pharmacy, Timisoara, Romania
| | - Gheorghe-Emilian Olteanu
- Department of Microscopic Morphology - Pathology, "Victor Babeș" University of Medicine and Pharmacy, Timisoara, Romania
- Centre for Gene and Cellular Therapies in Cancer-Oncogen, Timisoara, Romania
| | - Diana Herman
- Emergency County Hospital "Pius Brînzeu," Timisoara, Romania
| | - Denisa Anderco
- Emergency County Hospital "Pius Brînzeu," Timisoara, Romania
| | - Mihaela Iacob
- Emergency County Hospital "Pius Brînzeu," Timisoara, Romania
| | - Bianca Nataras
- Emergency County Hospital "Pius Brînzeu," Timisoara, Romania
| | - Alin Adrian Cumpanas
- Emergency County Hospital "Pius Brînzeu," Timisoara, Romania
- Department of Urology - "Victor Babeș" University of Medicine and Pharmacy, Timisoara, Romania
| | - Razvan Bardan
- Emergency County Hospital "Pius Brînzeu," Timisoara, Romania
- Department of Urology - "Victor Babeș" University of Medicine and Pharmacy, Timisoara, Romania
| | - Alis Dema
- Department of Microscopic Morphology - Pathology, "Victor Babeș" University of Medicine and Pharmacy, Timisoara, Romania
- Emergency County Hospital "Pius Brînzeu," Timisoara, Romania
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4
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Lim I, Mitsui R, Kameda M, Sellers DJ, Chess-Williams R, Hashitani H. Comparative effects of angiotensin II on the contractility of muscularis mucosae and detrusor in the pig urinary bladder. Neurourol Urodyn 2020; 40:102-111. [PMID: 33074588 DOI: 10.1002/nau.24548] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/05/2020] [Accepted: 10/07/2020] [Indexed: 01/20/2023]
Abstract
To explore contractile actions of angiotensin II (ATII) on the muscularis mucosae (MM) of the bladder, ATII-induced contractions were compared between MM and the detrusor smooth muscle (DSM) of the pig bladder by isometric tension recordings. Effects of ATII on spontaneous Ca2+ transients in MM were visualized using Cal-520 fluorescence. ATII receptor type 1 (ATR1) expression in MM and DSM was also examined by immunohistochemistry. ATII (1 nM-1 μM) caused phasic contractions of MM in a concentration-dependent manner, while ATII (10 nM-10 μM) had no or marginal effects on DSM contractility. ATII (100 nM)-induced MM contractions had an amplitude of approximately 70% of carbachol (1 μM)-induced or 90% of U46619 (100 nM)-induced contractions. Candesartan (10 nM), an ATR1 blocker, prevented the contractile effects of ATII (1 nM) in MM, while ATR1 immunofluorescence was greater in MM than DSM. ATII (10-100 pM) increased the frequency but not the amplitude of spontaneous Ca2+ transients in MM. Both urothelium-intact and -denuded MM strips developed comparable spontaneous phasic contractions, but ATII, carbachol and U46619-induced contractions were significantly larger in urothelium-denuded than urothelium-intact MM strips. In conclusion, the MM appears to have a much greater sensitivity to ATII compared with DSM that could well sense circulating ATII, suggesting that MM may be the predominant target of contractile actions induced by ATII in the bladder while the urothelium appears to inhibit MM contractility.
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Affiliation(s)
- Iris Lim
- Center for Urology, Faculty of Health Sciences & Medicine, Bond University, Gold Coast, Queensland, Australia
| | - Retsu Mitsui
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Masashi Kameda
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Donna Jayne Sellers
- Center for Urology, Faculty of Health Sciences & Medicine, Bond University, Gold Coast, Queensland, Australia
| | - Russ Chess-Williams
- Center for Urology, Faculty of Health Sciences & Medicine, Bond University, Gold Coast, Queensland, Australia
| | - Hikaru Hashitani
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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5
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Miyachi H, Kudo SE, Ichimasa K, Hisayuki T, Oikawa H, Matsudaira S, Kouyama Y, Kimura YJ, Misawa M, Mori Y, Ogata N, Kudo T, Kodama K, Hayashi T, Wakamura K, Katagiri A, Baba T, Hidaka E, Ishida F, Kohashi K, Hamatani S. Management of T1 colorectal cancers after endoscopic treatment based on the risk stratification of lymph node metastasis. J Gastroenterol Hepatol 2016; 31:1126-32. [PMID: 26641025 DOI: 10.1111/jgh.13257] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [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] [Received: 08/03/2015] [Revised: 11/13/2015] [Accepted: 11/30/2015] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND AIM Recent advances in endoscopic technology have allowed many T1 colorectal carcinomas to be resected endoscopically with negative margins. However, the criteria for curative endoscopic resection remain unclear. We aimed to identify risk factors for nodal metastasis in T1 carcinoma patients and hence establish the indication for additional surgery with lymph node dissection. METHODS Initial or additional surgery with nodal dissection was performed in 653 T1 carcinoma cases. Clinicopathological factors were retrospectively analyzed with respect to nodal metastasis. The status of the muscularis mucosae (MM grade) was defined as grade 1 (maintenance) or grade 2 (fragmentation or disappearance). The lesions were then stratified based on the risk of nodal metastasis. RESULTS Muscularis mucosae grade was associated with nodal metastasis (P = 0.026), and no patients with MM grade 1 lesions had nodal metastasis. Significant risk factors for nodal metastasis in patients with MM grade 2 lesions were attribution of women (P = 0.006), lymphovascular infiltration (P < 0.001), tumor budding (P = 0.045), and poorly differentiated adenocarcinoma or mucinous carcinoma (P = 0.007). Nodal metastasis occurred in 1.06% of lesions without any of these pathological factors, but in 10.3% and 20.1% of lesions with at least one factor in male and female patients, respectively. There was good inter-observer agreement for MM grade evaluation, with a kappa value of 0.67. CONCLUSIONS Stratification using MM grade, pathological factors, and patient sex provided more appropriate indication for additional surgery with lymph node dissection after endoscopic treatment for T1 colorectal carcinomas.
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Affiliation(s)
- Hideyuki Miyachi
- Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan
| | - Shin-Ei Kudo
- Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan
| | - Katsuro Ichimasa
- Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan
| | - Tomokazu Hisayuki
- Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan
| | - Hiromasa Oikawa
- Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan
| | - Shingo Matsudaira
- Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan
| | - Yuta Kouyama
- Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan
| | - Yui Jennifer Kimura
- Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan
| | - Masashi Misawa
- Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan
| | - Yuichi Mori
- Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan
| | - Noriyuki Ogata
- Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan
| | - Toyoki Kudo
- Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan
| | - Kenta Kodama
- Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan
| | - Takemasa Hayashi
- Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan
| | - Kunihiko Wakamura
- Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan
| | - Atsushi Katagiri
- Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan
| | - Toshiyuki Baba
- Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan
| | - Eiji Hidaka
- Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan
| | - Fumio Ishida
- Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan
| | - Kenichi Kohashi
- Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Shigeharu Hamatani
- Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan.,Department of Pathology, The Jikei University School of Medicine, Tokyo, Japan
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6
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Bombardi C, Grandis A, Gardini A, Sorteni C, Clavenzani P, Chiocchetti R. Expression of β2 adrenoceptors within enteric neurons of the horse ileum. Res Vet Sci 2013; 95:837-45. [PMID: 23941962 DOI: 10.1016/j.rvsc.2013.07.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 05/10/2013] [Accepted: 07/08/2013] [Indexed: 12/31/2022]
Abstract
The activity of the gastrointestinal tract is regulated through the activation of adrenergic receptors (ARs). Since data concerning the distribution of ARs in the horse intestine is virtually absent, we investigated the distribution of β2-AR in the horse ileum using double-immunofluorescence. The β2-AR-immunoreactivity (IR) was observed in most (95%) neurons located in submucosal plexus (SMP) and in few (8%) neurons of the myenteric plexus (MP). Tyrosine hydroxylase (TH)-IR fibers were observed close to neurons expressing β2-AR-IR. Since β2-AR is virtually expressed in most neurons located in the horse SMP and in a lower percentage of neurons in the MP, it is reasonable to retain that this adrenergic receptor could regulate the activity of both secretomotor neurons and motor neurons innervating muscle layers and blood vessels. The high density of TH-IR fibers near β2-AR-IR enteric neurons indicates that the excitability of these cells could be directly modulated by the sympathetic system.
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Affiliation(s)
- Cristiano Bombardi
- Department of Veterinary Medical Science, University of Bologna, 40064 Ozzano dell'Emilia, Bologna, Italy.
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7
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Abstract
The subepithelial intestinal myofibroblast is an important cell orchestrating many diverse functions in the intestine and is involved in growth and repair, tumorigenesis, inflammation, and fibrosis. The myofibroblast is but one of several α-smooth muscle actin-positive (α-SMA(+)) mesenchymal cells present within the intestinal lamina propria, including vascular pericytes, bone marrow-derived stem cells (mesenchymal stem cells or hematopoietic stem cells), muscularis mucosae, and the lymphatic pericytes (colon) and organized smooth muscle (small intestine) associated with the lymphatic lacteals. These other mesenchymal cells perform many of the functions previously attributed to subepithelial myofibroblasts. This review discusses the definition of a myofibroblast and reconsiders whether the α-SMA(+) subepithelial cells in the intestine are myofibroblasts or other types of mesenchymal cells, i.e., pericytes. Current information about specific, or not so specific, molecular markers of lamina propria mesenchymal cells is reviewed, as well as the origins of intestinal myofibroblasts and pericytes in the intestinal lamina propria and their replenishment after injury. Current concepts and research on stem cell therapy for intestinal inflammation are summarized. Information about the stem cell origin of intestinal stromal cells may inform future stem cell therapies to treat human inflammatory bowel disease (IBD).
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Affiliation(s)
| | | | | | - D. W. Powell
- Departments of 1Internal Medicine and ,2Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas
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8
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Abstract
The mesenchymal elements of the intestinal lamina propria reviewed here are the myofibroblasts, fibroblasts, mural cells (pericytes) of the vasculature, bone marrow-derived stromal stem cells, smooth muscle of the muscularis mucosae, and smooth muscle surrounding the lymphatic lacteals. These cells share similar marker molecules, origins, and coordinated biological functions previously ascribed solely to subepithelial myofibroblasts. We review the functional anatomy of intestinal mesenchymal cells and describe what is known about their origin in the embryo and their replacement in adults. As part of their putative role in intestinal mucosal morphogenesis, we consider the intestinal stem cell niche. Lastly, we review emerging information about myofibroblasts as nonprofessional immune cells that may be important as an alarm system for the gut and as a participant in peripheral immune tolerance.
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Affiliation(s)
- D.W. Powell
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555-0764
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555-0764
| | - I.V. Pinchuk
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555-0764
| | - J.I. Saada
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555-0764
| | - Xin Chen
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California 94143
| | - R.C. Mifflin
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555-0764
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Abstract
1. The tachykinin receptor present in the guinea-pig oesophageal mucosa that mediates contractile responses of the muscularis mucosae has been characterized, using functional in vitro experiments. 2. The NK(1) receptor-selective agonist, [Sar(9)(O(2))Met(11)]SP and the NK(3) receptor-selective agonists, [MePhe(7)]-NKB and senktide, produced no response at submicromolar concentrations. The NK(2) receptor-selective agonists, [Nle(10)]-NKA(4 - 10), and GR 64,349 produced concentration-dependent contractile effects with pD(2) values of 8.20+/-0.16 and 8.30+/-0.15, respectively. 3. The concentration-response curve to the non-selective agonist, NKA (pD(2)=8.13+/-0.04) was shifted significantly rightwards only by the NK(2) receptor-selective antagonist, GR 159,897 and was unaffected by the NK(1) receptor-selective antagonist, SR 140,333 and the NK(3) receptor-selective antagonist, SB 222,200. 4. The NK(2) receptor-selective antagonist, GR 159,897, exhibited an apparent competitive antagonism against the NK(2) receptor-selective agonist, GR 64,349 (apparent pK(B) value=9.29+/-0.16) and against the non-selective agonist, NKA (apparent pK(B) value=8.71+/-0.19). 5. The NK(2) receptor-selective antagonist, SR 48,968 exhibited a non-competitive antagonism against the NK(2) receptor-selective agonist, [Nle(10)]-NKA(4 - 10). The pK(B) value was 10.84+/-0.19.6. It is concluded that the guinea-pig isolated oesophageal mucosa is a useful preparation for studying the effects of NK(2) receptor-selective agonists and antagonists as the contractile responses to various tachykinins are mediated solely by NK(2) receptors.
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Affiliation(s)
- K P Kerr
- Department of Pharmaceutical Biology and Pharmacology, Victorian College of Pharmacy, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
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10
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Uchida K, Yuzuki R, Kamikawa Y. Pharmacological characterization of endothelin-induced contraction in the guinea-pig oesophageal muscularis mucosae. Br J Pharmacol 1998; 125:849-57. [PMID: 9831924 PMCID: PMC1571009 DOI: 10.1038/sj.bjp.0702140] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1. In the oesophageal muscularis mucosae, we examined the effects of endothelin-1 (ET-1), endothelin-2 (ET-2), endothelin-3 (ET-3) and sarafotoxin S6c (SX6c) as agonists, and FR139317, BQ-123 and RES-701-1 as endothelin receptor antagonists. 2. All of the endothelins produced tonic contractions which were frequently superimposed on rhythmic motility in a concentration-dependent manner. The order of potency (-log EC50) was ET-1 (8.61)=SX6c (8.65)>ET-2 (8.40)>ET-3 (8.18). 3. FR139317 (1-3 microM) and BQ-123 (1 microM) caused parallel rightward shifts of the concentration-response curve to ET-1, but at higher concentrations caused no further shift. RES-701-1 (3 microM) caused a rightward shift of the concentration-response curve to ET-1, while RES-701-1 (10 microM) had no additional effect. RES-701-1 (0.1-1 microM) concentration-dependently caused a rightward shift of the concentration-response curve to SX6c. The contraction to ET-1 (10 nM) in preparations desensitized to the actions of SX6c was greatly inhibited by pretreatment with FR139317 (10 microM). 4. Modulation of the Ca2+ concentration in the Krebs solution caused the concentration-response curve to ET-1 or SX6c to shift to the right and downward as external Ca2+ concentrations decreased. Verapamil (30 microM) abolished rhythmic motility induced by ET-1 or SX6c. Ni2+ (0.1 mM) weakly inhibited ET-1- or SX6c-induced tonic contraction. SK&F 96365 (60 microM) completely inhibited ET-1-induced contractions. 5. We conclude that there are two types of ET-receptors, excitatory ET(A)- and ET(B)-receptors in the oesophageal muscularis mucosae. These receptors mediate tonic contractions predominantly by opening receptor-operated Ca2+ channels (ROCs) and partly by opening T-type Ca2+ channels, and mediate rhythmic motility by opening L-type Ca2+ channels.
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Affiliation(s)
- K Uchida
- Department of Pharmacology, Dokkyo University School of Medicine, Mibu, Tochigi, Japan
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