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Luo Y, Tang Y, Xia Q, Liu J. The expression of endothelin type A and B receptors in the lateral wall of the mouse cochlea. Cell Mol Biol Lett 2007; 12:595-603. [PMID: 17607529 PMCID: PMC6275685 DOI: 10.2478/s11658-007-0027-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2007] [Accepted: 04/30/2007] [Indexed: 02/05/2023] Open
Abstract
Endothelin (ET), originally characterized as a vasoconstrictive peptide, has been found to have many different biological functions, including acting as a local hormonal regulator of pressure, fluid, ions and neurotransmitters in the inner ear. The objective of this study was to examine and quantify the mRNA expression of the endothelin type A and B receptors (ETAR and ETBR) in the strial vascularies (StV) and non-strial tissues (NSt) of the cochlear lateral wall using the real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR) technique. The mouse tissue samples were harvested and RNA was extracted. RT was performed to obtain cDNA, and then the mRNA expression of each gene was measured via real-time PCR. We found that both receptor subtypes were expressed in the cochlear lateral wall, with a predominance of ETAR over ETBR. We showed that the mRNA expression of the two receptor subtypes was higher in the StV with a 1.8 times higher level of ETAR and an 8.1 times higher level of ETBR mRNAs than in the adjacent NSt of the lateral wall tissue. This study shows the existence and the quantity of ET receptor subtypes in the StV and NSt of the mouse cochlea. Our results suggest that an endothelin-mediated response via two different receptors, ETAR and ETBR, may play an important role in the physiological functions of the cochlear lateral wall by maintaining the homeostatic environment of the cochlea.
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Affiliation(s)
- Yan Luo
- Department of Otorhinolaryngology, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Yuedi Tang
- Department of Otorhinolaryngology, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Qingjie Xia
- Department of Ophthalmology, Laboratory of Molecular Biology, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Jin Liu
- Department of Anesthesiology and Critical Care Medicine, West China Hospital of Sichuan University, Chengdu, Sichuan, China
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2
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Khan H, Naylor RJ, Tuladhar BR. Pharmacological characterization of endothelin receptors-mediated contraction in the mouse isolated proximal and distal colon. Br J Pharmacol 2006; 147:607-11. [PMID: 16432510 PMCID: PMC1751337 DOI: 10.1038/sj.bjp.0706657] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2005] [Revised: 10/20/2005] [Accepted: 12/13/2005] [Indexed: 01/23/2023] Open
Abstract
The study investigated the role of endothelin (ET) and the ET receptor subtypes ET(A) and ET(B) in mediating longitudinal contraction in the mouse proximal and distal colon. Cumulative concentration-response curves to a range of ET agonists (ET-1, ET-2, ET-3, (Ala(1,3,11,13)) ET and IRL 1620) were established by administering concentrations ranging from 0.01 nM to 0.3 microM. Concentration-response curves to ET-1, which exhibits a high affinity for both ET(A) and ET(B) receptor subtypes, were also established in the presence of the ET(A) antagonist BMS 182874 and the ET(B) antagonist IRL1038. The addition of the selective ET(A) receptor antagonist BMS 182874 caused a rightward shift of the concentration-response curve to ET-1 in both sections of the colon. The ET(B) receptor antagonist IRL1038 (0.3-1 microM) did not significantly effect the response to ET-1 in the proximal colon but caused a significant decrease in response towards higher concentrations ranges (>or=3 nM) in the distal colon. A comparison of the concentration-response curves to ET-1, ET-2 and ET-3 showed a rank order of potency ET-1>or=ET-2>>ET-3 in the proximal colon and ET-1>or=ET-2>or=ET-3 in the distal colon. The selective ET(B) receptor agonists, (Ala(1,3,11,13)) ET and IRL 1620 did not produce any response in the proximal sections of the colon but produced a smaller contraction in the distal segments. The data indicate that ET can contract the proximal tissues of the mouse colon predominantly via ET(A) receptors and in the distal tissues via ET(A) and ET(B) receptors.
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Affiliation(s)
- Humaira Khan
- School of Pharmacy, University of Bradford, Richmond Road, Bradford, W. Yorkshire BD7 1DP
| | - Robert J Naylor
- School of Pharmacy, University of Bradford, Richmond Road, Bradford, W. Yorkshire BD7 1DP
| | - Bishwa R Tuladhar
- School of Pharmacy, University of Bradford, Richmond Road, Bradford, W. Yorkshire BD7 1DP
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3
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Abstract
We investigated the effects of endothelin 3 (ET-3) on electrolyte transport in rat small intestine using a voltage clamp technique in Ussing's chamber. ET-3 diminished potential difference (PD) and short circuit current (Isc). ET-3 did not affect PD or Isc in low Na(+) and/or D-glucose-free medium. Phloridzine (an inhibitor of sodium-glucose cotransporter [SGLT1]) pretreatment abolished the effect of ET-3 on Isc. Methylene blue (a soluble guanylate cyclase inhibitor) or N-nitro-L-arginine methyl ester (a NOS inhibitor) pretreatment delayed the effect of ET-3 on PD and Isc. ET-3 enhanced NOS activity on enterocytes and systemic NO production. Then, ET-3 could inhibit SGLT1 with the participation of NO.
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Affiliation(s)
- L V González Bosc
- Cátedra de Biología Celular e Histología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires. Junín 956, 1er piso (1113), Buenos Aires, Argentina.
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4
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Egidy G, Juillerat-Jeanneret L, Korth P, Bosman FT, Pinet F. The endothelin system in normal human colon. Am J Physiol Gastrointest Liver Physiol 2000; 279:G211-22. [PMID: 10898765 DOI: 10.1152/ajpgi.2000.279.1.g211] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Endothelin (ET)-1 is a potent vasoconstrictor and mitogenic peptide that has a variety of biological effects in noncardiovascular tissues. The precise cellular distribution of the ET-1 system in the wall of the normal human colon was studied to identify the physiological role of ET in the gut. In situ hybridization revealed ET-converting enzyme-1 (ECE-1) mRNA in all vessels, the colon epithelium, and macrophages. Prepro-ET-1 (PPET-1) mRNA had a similar distribution except for a scattered signal in mucosal microvessels. ET(A) and ET(B) receptor mRNAs were mainly in the lamina propria, pericryptal myofibroblasts, microvessels, and mononuclear cells, with ET(A) mRNA more abundant than ET(B) mRNA. (125)I-ET-1 binding showed ET(B) along the crypts and in nerve fibers descending from the ganglionic plexus that contained PPET-1, ECE-1, and ET(B) transcripts, whereas glia contained ET(A) receptors. The finding of the entire ET system in the normal mucosa suggests its implication in some characteristic functions of the colon and its secretion as both a neuroactive and a vasoactive peptide.
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Affiliation(s)
- G Egidy
- Institut National de la Santé et de la Recherche Médicale, Collège de France, Paris, France
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5
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Abstract
The intestinal tract is a target organ for atrial natriuretic peptide (ANP), characterized by various biologic activities, immunoreactivity, as well as specific binding sites for ANP. A review of previous studies reveals that ANP is an important regulator of water and nutrient intake, which acts via multiple signaling pathways including activation of guanylyl cyclase to produce its biologic responses. As a regulator, the peptide locally controls hydrosaline balance and acute systemic effects. Therefore, ANP could also act as a local mediator or paracrine effector of intestinal function.
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Affiliation(s)
- L V González Bosc
- Cátedra de Biología Celular e Histología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires. Junin 956, 1er piso (1113), Buenos Aires, Argentina.
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6
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Reddix RA, Mullet D, Fertel R, Cooke HJ. Endogenous nitric oxide inhibits endothelin-1-induced chloride secretion in guinea pig colon. Nitric Oxide 1998; 2:28-36. [PMID: 9706740 DOI: 10.1006/niox.1998.0168] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Segments of guinea pig distal colon, stripped of the external muscle layers, were set up in flux chambers for measurement of short-circuit current (Isc) indicative of active, electrogenic ion transport. During neural blockade with tetrodotoxin, the nitric oxide scavenger, hemoglobin, and the nitric oxide synthase inhibitor, N omega-nitro-L-arginine (L-NNA), reduced Isc. The reduction in Isc in response to hemoglobin was reversed by L-arginine and blockers of chloride secretion, including bumetanide and diphenylamine-2-carboxylic acid, but not by the potassium channel blockers, barium and tetraethylammonium, nor by amiloride, an epithelial sodium channel blocker. The hemoglobin-induced reduction in Isc was not affected by blockade of prostaglandin synthesis with piroxicam. During neural blockade, the nitric oxide donors, sodium nitroprusside and NONOate, increased Isc which was abolished by piroxicam. Endothelin-1 (ET-1) also evoked an increase in Isc that was unaffected by amiloride and was inhibitable by bumetanide, chloride-free solutions, tetrodotoxin, piroxicam, and the ETA receptor antagonist, BQ123. The ETB receptor agonist, [Ala1,3,11,15]-endothelin-1, had no appreciable effect on Isc. Hemoglobin and L-NNA enhanced the ET-1-induced Isc response by about twofold without affecting prostaglandin E2 release or its secretory response. The results suggest that endogenous nitric oxide stimulates a low level of chloride secretion that is independent of prostaglandins, unlike nitric oxide donors which increase chloride secretion by releasing prostaglandins. In addition, endogenous nitric oxide suppresses ET-1-evoked chloride secretion by mechanisms that are unrelated to the release of prostaglandin E2 or its ability to stimulate epithelial cells. Endogenous nitric oxide may play an important role in modulating chloride secretion during ischemic challenge when endothelin levels are high.
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Affiliation(s)
- R A Reddix
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University, New Orleans 70112, USA
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7
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Kuhn M, Fuchs M, Beck FX, Martin S, Jähne J, Klempnauer J, Kaever V, Rechkemmer G, Forssmann WG. Endothelin-1 potently stimulates chloride secretion and inhibits Na(+)-glucose absorption in human intestine in vitro. J Physiol 1997; 499 ( Pt 2):391-402. [PMID: 9080369 PMCID: PMC1159314 DOI: 10.1113/jphysiol.1997.sp021936] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
1. Serosally added synthetic endothelin-1 (ET-1) increased short-circuit current (Isc) across isolated muscle-stripped human colonic mucosa in vitro. Bumetanide inhibited Isc responses, indicating that ET-1 stimulates electrogenic Cl- secretion. 2. In isolated human jejunal mucosa, ET-1 exhibited a concentration-dependent dual action. At low concentrations it induced rapid increases in Isc and these were inhibited by bumetanide. At a higher concentration (0.1 microM), ET-1 provoked a drastic and progressive decrease in Isc below the baseline value. 3. Pretreatment with phlorizin or omission of glucose from the Krebs-Ringer solution at the apical (luminal) side of the jejunal mucosa prevented the decreases in Isc evoked by ET-1, suggesting that the peptide inhibits the glucose-coupled electrogenic Na+ absorption. Indeed, flux experiments with D-[14C]glucose demonstrated that ET-1 decreases jejunal glucose absorption by approximately 80% within 30 min. 4. Electron microprobe analyses of cryosections of human jejunum showed that ET-1 (0.1 microM) evokes a significant decrease in intracellular Na+ concentrations of villus (not crypt) epithelial cells, suggesting that the peptide attenuates apical Na(+)-glucose entry by reducing the activity of the Na(+)-glucose cotransporter, SGLT1. 5. In the presence of tetrodotoxin (TTX), ET-1-induced Cl- secretion was significantly reduced, in both human jejunal and colonic mucosa. However, the inhibitory effect on jejunal Na(+)-glucose absorption was not affected by TTX. 6. ET-1 increases electrogenic Cl- secretion across human intestinal mucosa in vitro. This effect is mediated in part via the activation of enteric nerves. Responses of the human jejunal mucosa to high ET-1 concentrations exhibit a second component, namely the rapid inhibition of electrogenic Na(+)-glucose absorption, which might be mediated by an inhibition of the transport activity of SGLT1. This effect is independent from neuronal mediators. Our results suggest different cellular action sites for ET-1 in human small and large intestine.
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Affiliation(s)
- M Kuhn
- Lower Saxony Institute for Peptide Research, Hannover, Germany
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8
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Nussdorfer GG, Rossi GP, Belloni AS. The role of endothelins in the paracrine control of the secretion and growth of the adrenal cortex. INTERNATIONAL REVIEW OF CYTOLOGY 1997; 171:267-308. [PMID: 9066130 DOI: 10.1016/s0074-7696(08)62590-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Endothelins (ETs) are a family of vasoactive peptides (ET-1, ET-2, and ET-3) mainly secreted by vascular endothelium and widely distributed in the various body systems, where they play major autocrine/paracrine regulatory functions, acting via two subtypes of receptors (ETA and ETB): Adrenal cortex synthesizes and releases ETS and expresses both ETA and ETB. Zona glomerulosa possesses both ETA and ETB, whereas zona fasciculata/reticularis is almost exclusively provided with ETB. ETS exert a strong mineralocorticoid and a less intense glucocorticoid secretagogue action, mainly via ETB receptors. ETS also appear to enhance the growth and steroidogenic capacity of zona glomerulosa and to stimulate its proliferative activity. This trophic action of ETS is likely to be mediated mainly by ETA receptors. The intraadrenal release of ETS undergoes a multiple regulation, with the rise in blood flow rate and the local release of nitric oxide being the main stimulatory factors. Data are also available that indicate that ETS may also have a role in the pathophysiology of primary aldosteronism caused by adrenal adenomas and carcinomas.
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9
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Hogaboam CM, Muller MJ, Collins SM, Hunt RH. An orally active non-selective endothelin receptor antagonist, bosentan, markedly reduces injury in a rat model of colitis. Eur J Pharmacol 1996; 309:261-9. [PMID: 8874149 DOI: 10.1016/0014-2999(96)00276-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Activation of endothelial cells by vasoactive mediators, such as endothelins, may be an early, strategically important step in the initiation of inflammation in the intestine. In view of recent evidence that inflammatory bowel disease is associated with elevated intestinal concentrations of endothelins and upregulated expression of endothelin receptors on vascular endothelium in intestine, endothelins may become therapeutic targets in inflammatory bowel disease. The recent availability of an orally active, mixed endothelin receptor antagonist, bosentan, allowed us to examine the role of endothelins in a rat model of colitis. Colitis was induced by intra-rectal administration of trinitrobenzene sulphonic acid. In each treatment group, rats were treated with bosentan (10-60 mg/kg p.o.) 24 and 2 h prior to (pre-dose) or 1 h after the induction (post-induction) of colitis and all animals were treated every 24 h thereafter for 5 days. On day 6, stool consistency and the presence of adhesions in the peritoneal cavity were accessed. Colonic tissue samples were removed for determination of macroscopic and microscopic tissue injury, and myeloperoxidase activity. Colitis was typified by tissue ulceration in the distal colon and a corresponding 35-fold increase in myeloperoxidase activity compared to non-inflamed controls. Daily treatment with bosentan dose-dependently reduced colonic damage and myeloperoxidase activity when bosentan was given prior to induction of colitis. In the pre-dose group, the greatest beneficial effect of bosentan was observed at 60 mg/kg; colonic damage and granulocyte infiltration were attenuated by > 80%. A partial therapeutic effect of bosentan was also observed at 60 mg/kg when the pre-treatment regimen was excluded. These findings demonstrate that an orally active, mixed endothelin receptor antagonist has marked protective and therapeutic effects in an animal model of colitis.
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Affiliation(s)
- C M Hogaboam
- Department of Medicine, McMaster University, Hamilton, ON, Canada
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10
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Kajita H, Kotera T, Shirakata Y, Ueda S, Okuma M, Oda-Ohmae K, Takimoto M, Urade Y, Okada Y. A maxi Cl- channel coupled to endothelin B receptors in the basolateral membrane of guinea-pig parietal cells. J Physiol 1995; 488 ( Pt 1):65-75. [PMID: 8568666 PMCID: PMC1156701 DOI: 10.1113/jphysiol.1995.sp020946] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
1. To study endothelin (ET) receptors in guinea-pig stomach, ET-binding assays and in vitro autoradiography were performed on fundic cell suspensions and on sections of the fundus, respectively. ETA and ETB receptor subtypes were found to coexist in the parietal cells. 2. Endothelin 1 (ET-1) added to the (basolateral) bathing solution was found to activate noisy whole-cell Cl- currents within about 1 min in both single, isolated parietal cells and those within gastric glands obtained from the fundus. 3. ET-1-induced Cl- currents were rapidly blocked by a Cl- channel blocker (NPPB) added to the (basolateral) bathing solution in a concentration-dependent manner with a half-maximum inhibition concentration of 33 microM. 4. The anion selectivity sequence of the ET-1-induced conductance was I- > Br- > Cl- > F-, corresponding to Eisenman's sequence I. 5. Changes in extracellular pH between 5 and 8 did not affect the ET-1-induced activation of Cl- currents. 6. Similar activating effects were also observed with ET-3 and a specific ETB receptor agonist (IRL1620). An ETB receptor antagonist (IRL1720) prevented the ET-1 effect, whereas an ETA-selective antagonist (FR139317 or BQ123) failed to antagonize the ET-1 effect. 7. In the whole-cell mode, unitary Cl- channel events could be observed in association with ET-1-activated macroscopic currents. The single-channel conductances were around 200 and 350 pS at negative and positive membrane potentials, respectively. 8. It is concluded that gastric parietal cells of guinea-pig possess pH-insensitive 'maxi' Cl- channels coupled to ETB receptors in the basolateral membrane.
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Affiliation(s)
- H Kajita
- Department of Internal Medicine, Faculty of Medicine, Kyoto University, Japan
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11
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Eaker E, Sallustio J, Kohler J, Visner G. Endothelin-1 expression in myenteric neurons cultured from rat small intestine. REGULATORY PEPTIDES 1995; 55:167-77. [PMID: 7754103 DOI: 10.1016/0167-0115(94)00103-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Endothelin is a potent vasoactive peptide. More recently, endothelin-1 (ET-1) has been found in neural tissues such as spinal cord, brain and peripheral ganglion cells. Inagaki (Gastroenterology 101 (1991) 47) reported evidence of ET-1-like immunoreactivity in enteric neurons, but there are no reports of ET-1 peptide or mRNA expression specifically in myenteric neurons. Using a primary culture of myenteric neurons, we set out to evaluate ET-1 peptide and mRNA expression. Myenteric neurons were cultured using a dissection and enzyme dispersion technique. ET-1 reactivity was localized to neurons and ET-1 levels from cells and media were assayed by radioimmunoassay under a variety of media conditions or with depolarizing buffer or veratridine (75 microM). Prepro ET-1 mRNA expression was determined by Northern analysis of total RNA utilizing a rat ET-1 cDNA. ET-1 immunoreactivity was observed almost exclusively in myenteric neurons. Cells contained 0.78 pg/micrograms protein and did not vary with variations in media conditions. Basal release/secretion into media occurred but was not enhanced by depolarizing media or veratridine. High levels of ET-1 mRNA expression were identified. These results of high level constitutive expression of ET-1 linked with previous reports of ET-1 modulation of cholinergic intestinal smooth muscle contraction suggest a neuromodulatory role.
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MESH Headings
- Animals
- Animals, Newborn
- Autoradiography
- Blotting, Northern
- Cells, Cultured
- Chromatography, High Pressure Liquid
- Endothelins/biosynthesis
- Endothelins/genetics
- Fibroblasts/cytology
- Fibroblasts/metabolism
- Immunohistochemistry
- Intestine, Small/cytology
- Intestine, Small/innervation
- Intestine, Small/metabolism
- Microscopy, Fluorescence
- Muscle Contraction/physiology
- Muscle, Smooth/physiology
- Myenteric Plexus/cytology
- Myenteric Plexus/metabolism
- Neuroglia/cytology
- Neuroglia/metabolism
- Neurons/cytology
- Neurons/metabolism
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Radioimmunoassay
- Rats
- Rats, Sprague-Dawley
- Veratridine/chemistry
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Affiliation(s)
- E Eaker
- Department of Medicine, College of Medicine, University of Florida, Gainesville, USA
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12
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Rae GA, Calixto JB, D'Orléans-Juste P. Effects and mechanisms of action of endothelins on non-vascular smooth muscle of the respiratory, gastrointestinal and urogenital tracts. REGULATORY PEPTIDES 1995; 55:1-46. [PMID: 7724825 DOI: 10.1016/0167-0115(94)00098-i] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- G A Rae
- Department of Pharmacology, Universidade Federal de Santa Catarina, Florianópolis, Brazil
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13
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Mehta RS, Hartle DK. Effects of total fasting or chronic food restriction on plasma endothelin levels in rats. Physiol Behav 1994; 56:407-10. [PMID: 7938257 DOI: 10.1016/0031-9384(94)90214-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We tested the effects of 24- and 48-h fasting and 40% calorie restriction stresses on plasma endothelin (ET)-1,2 levels in male Sprague-Dawley rats. Plasma ET-1,2 levels in pg/ml were lower in 24-h fasted rats (15.48 +/- 3.49), 48-h fasted rats (5.28 +/- 4.32), and in chronically food-deprived rats (R) (10.49 +/- 6.28) compared to ad lib-fed (AL) rats (21.23 +/- 9.38). The R rats were pair-fed 40% fewer calories than AL rats. We conclude that calorie restriction or total food deprivation stress decreases plasma ET-1,2 levels, unlike many other forms of physiological stress that have been shown to increase plasma ET-1,2 levels.
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Affiliation(s)
- R S Mehta
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Georgia, Athens 30602-2356
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14
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Wilson C, Hargreaves RB. Inhibition of the pharmacological effects of endothelin. PROGRESS IN MEDICINAL CHEMISTRY 1994; 31:371-410. [PMID: 8029479 DOI: 10.1016/s0079-6468(08)70025-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- C Wilson
- ZENECA Pharmaceuticals, Cardiovascular Research Department, Alderley Park, Macclesfield, Cheshire, U.K
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15
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Kiyohara T, Okuno M, Nakanishi T, Shinomura Y, Matsuzawa Y. Effect of endothelin 1 on ion transport in isolated rat colon. Gastroenterology 1993; 104:1328-36. [PMID: 8482447 DOI: 10.1016/0016-5085(93)90341-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Endothelin may play a significant role in the regulation of gastrointestinal function because it has a variety of biological activities and because endothelin-like immunoreactivity as well as its specific binding sites have been found in the gastrointestinal tract. This study investigated the secretory effect and mechanism of action of endothelin 1 in mammalian large intestine. METHODS Distal colonic segments from Sprague-Dawley rats were stripped of their muscle layers and mounted in Ussing chambers. The effects of endothelin 1 on short-circuit current in rat colonic mucosa were studied in the absence or presence of specific inhibitors. Transmural unidirectional 22Na+ and 36Cl- fluxes and endothelin 1-induced prostacyclin release were also measured. RESULTS Serosal addition of endothelin 1 evoked a sustained increase in short-circuit current that was significantly reduced by tetrodotoxin or atropine, and virtually abolished by a selective endothelin A receptor antagonist (BQ-123), furosemide, piroxicam, d,I-verapamil, or removal of serosal calcium. Hexamethonium, amiloride, diphenhydramine, or a specific platelet-activating factor antagonist (CV-6209) did not influence the response to endothelin 1. Endothelin 1 significantly decreased net sodium and net chloride absorption and induced a marked increase in prostacyclin release from the serosal surface of stripped colonic mucosa. CONCLUSIONS Endothelin 1 has a secretory effect in rat colon. Its action seems to be mediated by cyclo-oxygenase products and enteric nerves via the activation of an endothelin A receptor.
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Affiliation(s)
- T Kiyohara
- Second Department of Internal Medicine, Osaka University Medical School, Japan
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16
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Smith PL. Effects of the neuroimmune mediators, peptidoleukotrienes, endothelin, and interleukin-1 on intestinal ion transport. Ann N Y Acad Sci 1992; 664:260-74. [PMID: 1456656 DOI: 10.1111/j.1749-6632.1992.tb39766.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- P L Smith
- Department of Drug Delivery, SmithKline Beecham, King of Prussia, Pennsylvania 19406
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17
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Roden M, Plass H, Vierhapper H, Turnheim K. Endothelin-1 stimulates chloride and potassium secretion in rabbit descending colon. Pflugers Arch 1992; 421:163-7. [PMID: 1326745 DOI: 10.1007/bf00374823] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The vasoactive peptide endothelin-1 (ET-1) which is present in high concentrations in the colon, causes concentration-dependent electrogenic Cl- secretion in rabbit descending colon. This effect is half-maximal at 0.11 mumol/l. Like other secretagogues, ET-1 also stimulates K+ secretion. The secretory effect of ET-1 is associated with increased release of prostaglandin E2 from the serosal surface of the mucosa. ET-1-induced Cl- secretion is completely inhibited by the loop diuretic bumetanide and by indomethacin and quinacrine, inhibitors of prostaglandin synthesis. Neuronal mechanisms do not seem to be involved, as tetrodotoxin did not affect the secretory response to ET-1 significantly. On the other hand, neither the catalytic activity nor the transport function of the Na+/K(+)-ATPase of rabbit colon epithelium is affected by endothelin-1 (ET-1) in concentrations up to 10 mumol/l. It is concluded that ET-1 causes Cl- and K+ secretion by stimulating phospholipase A2 and release of prostaglandins, whereas Na+ transport is not altered.
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Affiliation(s)
- M Roden
- Pharmakologisches Institut, Universität Wien, Austria
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