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Central endothelin ET B receptor activation reduces blood pressure and catecholaminergic activity in the olfactory bulb of deoxycorticosterone acetate-salt hypertensive rats. Eur J Pharmacol 2020; 885:173543. [PMID: 32896551 DOI: 10.1016/j.ejphar.2020.173543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 09/01/2020] [Accepted: 09/03/2020] [Indexed: 11/23/2022]
Abstract
Endothelins regulate catecholaminergic activity in the olfactory bulb (OB) in normotensive and hypertensive animals. Administration of an endothelin ETA receptor antagonist decreases blood pressure in deoxycorticosterone acetate-salt (DOCA-salt) rats along with a reduction in tyrosine hydroxylase (TH) activity and expression. In the present work, we sought to establish the role of brain endothelin ETB receptor on blood pressure regulation and its relationship with the catecholaminergic system within the OB of DOCA-Salt rats. Sprague-Dawley male rats were divided into control and DOCA-Salt groups. Blood pressure, heart rate and TH activity as well as neuronal nitric oxide synthase (nNOS) expression were assessed following IRL-1620 (selective endothelin ETB receptor agonist) applied to be brain. IRL-1620 significantly reduced systolic, diastolic, and mean arterial pressure in DOCA-Salt hypertensive rats. It also decreased TH activity, TH total and phosphorylated forms expression as well as its mRNA in the OB of hypertensive animals. The expression of phospho-Ser1417-nNOS, which reflects nNOS activation, was significantly decreased in the of OB of DOCA-salt rats, but it was enhanced by IRL-1620. These findings suggest that DOCA-Salt hypertension depends on endogenous central endothelin ETA receptor activity, rather than on ETB, and that low endothelin ETB stimulation is essential for blood pressure elevation in this animal model. The effect of endothelin ETA receptor antagonism may also result from endothelin ETB receptor overstimulation. The present study shows that endothelin receptors are involved in the regulation of TH in the OB and that such changes are likely implicated in the hemodynamic control and sympathetic outflow.
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SCF-KIT signaling induces endothelin-3 synthesis and secretion: Thereby activates and regulates endothelin-B-receptor for generating temporally- and spatially-precise nitric oxide to modulate SCF- and or KIT-expressing cell functions. PLoS One 2017; 12:e0184154. [PMID: 28880927 PMCID: PMC5589172 DOI: 10.1371/journal.pone.0184154] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 08/19/2017] [Indexed: 01/11/2023] Open
Abstract
We demonstrate that SCF-KIT signaling induces synthesis and secretion of endothelin-3 (ET3) in human umbilical vein endothelial cells and melanoma cells in vitro, gastrointestinal stromal tumors, human sun-exposed skin, and myenteric plexus of human colon post-fasting in vivo. This is the first report of a physiological mechanism of ET3 induction. Integrating our finding with supporting data from literature leads us to discover a previously unreported pathway of nitric oxide (NO) generation derived from physiological endothelial NO synthase (eNOS) or neuronal NOS (nNOS) activation (referred to as the KIT-ET3-NO pathway). It involves: (1) SCF-expressing cells communicate with neighboring KIT-expressing cells directly or indirectly (cleaved soluble SCF). (2) SCF-KIT signaling induces timely local ET3 synthesis and secretion. (3) ET3 binds to ETBR on both sides of intercellular space. (4) ET3-binding-initiated-ETBR activation increases cytosolic Ca2+, activates cell-specific eNOS or nNOS. (5) Temporally- and spatially-precise NO generation. NO diffuses into neighboring cells, thus acts in both SCF- and KIT-expressing cells. (6) NO modulates diverse cell-specific functions by NO/cGMP pathway, controlling transcriptional factors, or other mechanisms. We demonstrate the critical physiological role of the KIT-ET3-NO pathway in fulfilling high demand (exceeding basal level) of endothelium-dependent NO generation for coping with atherosclerosis, pregnancy, and aging. The KIT-ET3-NO pathway most likely also play critical roles in other cell functions that involve dual requirement of SCF-KIT signaling and NO. New strategies (e.g. enhancing the KIT-ET3-NO pathway) to harness the benefit of endogenous eNOS and nNOS activation and precise NO generation for correcting pathophysiology and restoring functions warrant investigation.
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Szteyn K, Gomez R, Berg KA, Jeske NA. Divergence in endothelin-1- and bradykinin-activated store-operated calcium entry in afferent sensory neurons. ASN Neuro 2015; 7:7/2/1759091415578714. [PMID: 25873305 PMCID: PMC4397213 DOI: 10.1177/1759091415578714] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Endothelin-1 (ET-1) and bradykinin (BK) are endogenous peptides that signal through Gαq/11-protein coupled receptors (GPCRs) to produce nociceptor sensitization and pain. Both peptides activate phospholipase C to stimulate Ca2+ accumulation, diacylglycerol production, and protein kinase C activation and are rapidly desensitized via a G-protein receptor kinase 2-dependent mechanism. However, ET-1 produces a greater response and longer lasting nocifensive behavior than BK in multiple models, indicating a potentially divergent signaling mechanism in primary afferent sensory neurons. Using cultured sensory neurons, we demonstrate significant differences in both Ca2+ influx and Ca2+ release from intracellular stores following ET-1 and BK treatments. As intracellular store depletion may contribute to the regulation of other signaling cascades downstream of GPCRs, we concentrated our investigation on store-operated Ca2+ channels. Using pharmacological approaches, we identified transient receptor potential canonical channel 3 (TRPC3) as a dominant contributor to Ca2+ influx subsequent to ET-1 treatment. On the other hand, BK treatment stimulated Orai1 activation, with only minor input from TRPC3. Taken together, data presented here suggest that ET-1 signaling targets TRPC3, generating a prolonged Ca2+ signal that perpetuates nocifensive responses. In contrast, Orai1 dominates as the downstream target of BK receptor activation and results in transient intracellular Ca2+ increases and abridged nocifensive responses.
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Affiliation(s)
- Kalina Szteyn
- Department of Oral and Maxillofacial Surgery, University of Texas Health Science Center at San Antonio, TX, USA
| | - Ruben Gomez
- Department of Oral and Maxillofacial Surgery, University of Texas Health Science Center at San Antonio, TX, USA
| | - Kelly A Berg
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, TX, USA
| | - Nathaniel A Jeske
- Department of Oral and Maxillofacial Surgery, University of Texas Health Science Center at San Antonio, TX, USA Department of Pharmacology, University of Texas Health Science Center at San Antonio, TX, USA Department of Physiology, University of Texas Health Science Center at San Antonio, TX, USA
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Vatta MS, Bianciotti LG, Guil MJ, Hope SI. Regulation of the Norepinephrine Transporter by Endothelins. HORMONES AND TRANSPORT SYSTEMS 2015; 98:371-405. [DOI: 10.1016/bs.vh.2014.12.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Lehmann LH, Stanmore DA, Backs J. The role of endothelin-1 in the sympathetic nervous system in the heart. Life Sci 2014; 118:165-72. [PMID: 24632477 DOI: 10.1016/j.lfs.2014.03.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Revised: 02/10/2014] [Accepted: 03/01/2014] [Indexed: 12/15/2022]
Abstract
Endothelin-1 (ET1) is a peptide that was initially identified as a strong inductor of vascular contraction. In the last 25 years, there have been several biological processes identified in which ET1 seems to play a critical role. In particular, genetic studies have unveiled that ET1 is important for neuronal development, growth and function. Experimental studies identified ET1 as a regulator of the interaction between sympathetic neurons and cardiac myocytes. This might be of clinical importance since patients suffering from heart failure are characterized by disrupted norepinephrine homeostasis in the heart. This review summarizes the important findings on the role of ET1 for sympathetic neurons and norepinephrine homeostasis in the heart.
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Affiliation(s)
- Lorenz H Lehmann
- Research Unit Cardiac Epigenetics, Department of Cardiology, University of Heidelberg, and DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - David A Stanmore
- Research Unit Cardiac Epigenetics, Department of Cardiology, University of Heidelberg, and DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Johannes Backs
- Research Unit Cardiac Epigenetics, Department of Cardiology, University of Heidelberg, and DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, 69120 Heidelberg, Germany.
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Endothelin-1 and -3 induce choleresis in the rat through ETB receptors coupled to nitric oxide and vagovagal reflexes. Clin Sci (Lond) 2013; 125:521-32. [PMID: 23642207 DOI: 10.1042/cs20120633] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We have reported previously that centrally applied ET (endothelin)-1 and ET-3 induce either choleresis or cholestasis depending on the dose. In the present study, we sought to establish the role of these endothelins in the short-term peripheral regulation of bile secretion in the rat. Intravenously infused endothelins induced significant choleresis in a dose-dependent fashion, ET-1 being more potent than ET-3. Endothelins (with the exception of a higher dose of ET-1) did not affect BP (blood pressure), portal venous pressure or portal blood flow. ET-1 and ET-3 augmented the biliary excretion of bile salts, glutathione and electrolytes, suggesting enhanced bile acid-dependent and -independent bile flows. ET-induced choleresis was mediated by ET(B) receptors coupled to NO and inhibited by truncal vagotomy, atropine administration and capsaicin perivagal application, supporting the participation of vagovagal reflexes. RT (reverse transcription)-PCR and Western blot analysis revealed ETA and ET(B) receptor expression in the vagus nerve. Endothelins, through ET(B) receptors, augmented the hepatocyte plasma membrane expression of Ntcp (Na⁺/taurocholate co-transporting polypeptide; Slc10a1), Bsep (bile-salt export pump; Abcb11), Mrp2 (multidrug resistance protein-2; Abcc2) and Aqp8 (aquaporin 8). Endothelins also increased the mRNAs of these transporters. ET-1 and ET-3 induced choleresis mediated by ET(B) receptors coupled to NO release and vagovagal reflexes without involving haemodynamic changes. Endothelin-induced choleresis seems to be caused by increased plasma membrane translocation and transcriptional expression of key bile transporters. These findings indicate that endothelins are able to elicit haemodynamic-independent biological effects in the liver and suggest that these peptides may play a beneficial role in pathophysiological situations where bile secretion is impaired.
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Regulation of cardiac nitric oxide signaling by nuclear β-adrenergic and endothelin receptors. J Mol Cell Cardiol 2013; 62:58-68. [PMID: 23684854 DOI: 10.1016/j.yjmcc.2013.05.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 04/11/2013] [Accepted: 05/07/2013] [Indexed: 01/19/2023]
Abstract
At the cell surface, βARs and endothelin receptors can regulate nitric oxide (NO) production. β-adrenergic receptors (βARs) and type B endothelin receptors (ETB) are present in cardiac nuclear membranes and regulate transcription. The present study investigated the role of the NO pathway in the regulation of gene transcription by these nuclear G protein-coupled receptors. Nitric oxide production and transcription initiation were measured in nuclei isolated from the adult rat heart. The cell-permeable fluorescent dye 4,5-diaminofluorescein diacetate (DAF2 DA) was used to provide a direct assessment of nitric oxide release. Both isoproterenol and endothelin increased NO production in isolated nuclei. Furthermore, a β3AR-selective agonist, BRL 37344, increased NO synthesis whereas the β1AR-selective agonist xamoterol did not. Isoproterenol increased, whereas ET-1 reduced, de novo transcription. The NO synthase inhibitor l-NAME prevented isoproterenol from increasing either NO production or de novo transcription. l-NAME also blocked ET-1-induced NO-production but did not alter the suppression of transcription initiation by ET-1. Inhibition of the cGMP-dependent protein kinase (PKG) using KT5823 also blocked the ability of isoproterenol to increase transcription initiation. Furthermore, immunoblotting revealed eNOS, but not nNOS, in isolated nuclei. Finally, caged, cell-permeable isoproterenol and endothelin-1 analogs were used to selectively activate intracellular β-adrenergic and endothelin receptors in intact adult cardiomyocytes. Intracellular release of caged ET-1 or isoproterenol analogs increased NO production in intact adult cardiomyocytes. Hence, activation of the NO synthase/guanylyl cyclase/PKG pathway is necessary for nuclear β3ARs to increase de novo transcription. Furthermore, we have demonstrated the potential utility of caged receptor ligands in selectively modulating signaling via endogenous intracellular G protein-coupled receptors.
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Goto A, Sumiyama K, Kamioka Y, Nakasyo E, Ito K, Iwasaki M, Enomoto H, Matsuda M. GDNF and endothelin 3 regulate migration of enteric neural crest-derived cells via protein kinase A and Rac1. J Neurosci 2013; 33:4901-12. [PMID: 23486961 PMCID: PMC6618995 DOI: 10.1523/jneurosci.4828-12.2013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 01/22/2013] [Accepted: 01/25/2013] [Indexed: 11/21/2022] Open
Abstract
Enteric neural crest-derived cells (ENCCs) migrate from the anterior foregut in a rostrocaudal direction to colonize the entire gastrointestinal tract and to form the enteric nervous system. Genetic approaches have identified many signaling molecules regulating the migration of ENCCs; however, it remains elusive how the activities of the signaling molecules are regulated spatiotemporally during migration. In this study, transgenic mice expressing biosensors based on Förster resonance energy transfer were generated to video the activity changes of the signaling molecules in migrating ENCCs. In an organ culture of embryonic day 11.25 (E11.25) to E13 guts, ENCCs at the rostral wavefront migrated as a cellular chain faster than the following ENCCs that formed a network. The faster-migrating cells at the wavefront exhibited lower protein kinase A (PKA) activity than did the slower-migrating trailing cells. The activities of Rac1 and Cdc42 exhibited an inverse correlation with the PKA activity, and PKA activation decreased the Rac1 activity and migration velocity. PKA activity in ENCCs was correlated positively with the distribution of GDNF and inversely with the distribution of endothelin 3 (ET-3). Accordingly, PKA was activated by GDNF and inhibited by ET-3 in cultured ENCCs. Finally, although the JNK and ERK pathways were previously reported to control the migration of ENCCs, we did not find any correlation of JNK or ERK activity with the migration velocities. These results suggest that external cues regulate the migration of ENCCs by controlling PKA activity, but not ERK or JNK activity, and argue for the importance of live imaging of signaling molecule activities in developing organs.
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Affiliation(s)
- Akihiro Goto
- Laboratory of Bioimaging and Cell Signaling, Graduate School of Biostudies, and
| | - Kenta Sumiyama
- Division of Population Genetics, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Yuji Kamioka
- Department of Pathology and Biology of Diseases, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8315, Japan
| | - Eiji Nakasyo
- Life & Industrial Products Development Department 1, R&D Division, Olympus Corporation, Hachioji, Tokyo 192-8507, Japan, and
| | - Keisuke Ito
- Laboratory for Neuronal Differentiation and Regeneration, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
| | - Mitsuhiro Iwasaki
- Laboratory for Neuronal Differentiation and Regeneration, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
| | - Hideki Enomoto
- Laboratory for Neuronal Differentiation and Regeneration, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
| | - Michiyuki Matsuda
- Laboratory of Bioimaging and Cell Signaling, Graduate School of Biostudies, and
- Department of Pathology and Biology of Diseases, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8315, Japan
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Chatfield DA, Brahmbhatt DH, Sharp T, Perkes IE, Outrim JG, Menon DK. Juguloarterial endothelin-1 gradients after severe traumatic brain injury. Neurocrit Care 2011; 14:55-60. [PMID: 20652766 DOI: 10.1007/s12028-010-9413-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Endothelin-1 (ET-1) is a potent vasoconstrictor and is thought to be responsible for secondary ischemia and vasogenic edema after traumatic brain injury (TBI). Both CSF and plasma concentrations have been shown to be increased after TBI, but there is little evidence to confirm an intracranial site of production. METHODS Using paired arterial and jugular venous bulb sampling, we measured arterial and jugular levels of ET-1 and its precursor, big endothelin (Big ET), and calculated juguloarterial (JA) gradients for the first 5 days post-TBI. RESULTS Arterial levels of both Big ET and ET-1 were maximal on day 1 post-TBI, and decreased thereafter (P < 0.05). Arterial levels of Big ET and ET-1 showed correlation across all 5 days of the study (r(2) = 0.25, P < 0.001). While there was no significant JA gradient for Big ET, significant gradients were observed for ET-1 on days 1-4 post-TBI (P < 0.05). There was no correlation between JA gradients for Big ET and ET-1 (r(2) < 0.1, P > 0.9). These data suggest parenchymal production of ET-1 by brain tissue with spill over into the blood, rather than local intraluminal cleavage of Big ET in the cerebral vasculature. Systemic ET-1 levels and JA gradients of ET-1 were unrelated to the injury severity, APACHE II score, Marshall Grade, the presence of subarachnoid or subdural hemorrhage, or eventual outcome. CONCLUSIONS These findings confirm the synthesis of Big ET and its cleavage to ET-1 within the brain after TBI. More work is needed to elucidate the pathophysiological role and the outcome impact of ET-1 generation after TBI.
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Affiliation(s)
- Doris A Chatfield
- Division of Anaesthesia, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK
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Mondillo C. La histamina en el testículo: nuevas funciones a través de receptores clásicos H1 y H2. Rev Int Androl 2011. [DOI: 10.1016/s1698-031x(11)70014-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Kohan DE, Rossi NF, Inscho EW, Pollock DM. Regulation of blood pressure and salt homeostasis by endothelin. Physiol Rev 2011; 91:1-77. [PMID: 21248162 DOI: 10.1152/physrev.00060.2009] [Citation(s) in RCA: 276] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Endothelin (ET) peptides and their receptors are intimately involved in the physiological control of systemic blood pressure and body Na homeostasis, exerting these effects through alterations in a host of circulating and local factors. Hormonal systems affected by ET include natriuretic peptides, aldosterone, catecholamines, and angiotensin. ET also directly regulates cardiac output, central and peripheral nervous system activity, renal Na and water excretion, systemic vascular resistance, and venous capacitance. ET regulation of these systems is often complex, sometimes involving opposing actions depending on which receptor isoform is activated, which cells are affected, and what other prevailing factors exist. A detailed understanding of this system is important; disordered regulation of the ET system is strongly associated with hypertension and dysregulated extracellular fluid volume homeostasis. In addition, ET receptor antagonists are being increasingly used for the treatment of a variety of diseases; while demonstrating benefit, these agents also have adverse effects on fluid retention that may substantially limit their clinical utility. This review provides a detailed analysis of how the ET system is involved in the control of blood pressure and Na homeostasis, focusing primarily on physiological regulation with some discussion of the role of the ET system in hypertension.
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Affiliation(s)
- Donald E Kohan
- Division of Nephrology, University of Utah Health Sciences Center, Salt Lake City, Utah 84132, USA.
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Xu DY, Wu B, Li ZQ, Wang QP, Zhang Y, Xue F, Ji JF. Expression of endothelin receptor subtypes in the spiral ganglion neurons of the guinea pig. Int J Pediatr Otorhinolaryngol 2010; 74:164-7. [PMID: 19959247 DOI: 10.1016/j.ijporl.2009.11.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 10/27/2009] [Accepted: 11/01/2009] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Endothelin 1 has many biological activities including regulating the functions of auditory system. The present study aimed to investigate the expression of the endothelin receptors in spiral ganglion neurons and its significance in the auditory transmission. METHODS The cochleae of healthy guinea pigs were fixed, decalcified, embedded in paraffin and serially sectioned. The expression of endothelin receptor subunits, ET receptor A (ET-A) and ET receptor B (ET-B), was examined in the spiral ganglion neurons of guinea pig using immunohistochemical technique. RESULTS Different degrees of ET-A and ET-B positive reactivity appeared in all spiral ganglion neurons from the basal turn to the apical turn. CONCLUSIONS These findings support the suggestion that endothelin via the endothelin receptor may play a physiological role in the spiral ganglion neurons.
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Affiliation(s)
- Ding-Yuan Xu
- Department of Otorhinolaryngology, Jinling Hospital, Clinical School of Nanjing, University, 305 East Zhongshan Road, Nanjing 210002, China
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Ohkita M, Takaoka M, Matsumura Y. Drug discovery for overcoming chronic kidney disease (CKD): the endothelin ET B receptor/nitric oxide system functions as a protective factor in CKD. J Pharmacol Sci 2009; 109:7-13. [PMID: 19151534 DOI: 10.1254/jphs.08r10fm] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Accelerated cardiovascular disease (CVD) is a frequent complication of renal disease. Chronic kidney disease (CKD) develops hypertension and dyslipidemia, which in turn can contribute to the progression of renal failure. There is general agreement that endothelin-1 (ET-1), which acts through the two subtypes of receptor ET(A) and ET(B), plays important physiological roles in the regulation of normal cardiovascular function and that excessive ET-1 production is linked to CVD and CKD. Although selective ET(A) or nonselective ET(A)/ET(B) receptor antagonisms have been recognized as a potential strategy for treatment of several cardiovascular disease, it remains unclear which of the antagonisms is suitable for the individuals with CKD because upregulation of the nitric oxide (NO) system via ET(B) receptor is responsible for renal function such as natriuresis, diuresis, and glomerular hemodynamics. Our findings clearly indicate that the blockade of ET receptors, in particular ET(A)-receptor antagonism, not only produces a potential renoprotective effect in CKD but also reduces the risk of CVD. In contrast, pharmacological blockade or genetic deficiency of ET(B) receptor seems to aggravate CKD and CVD in several experimental models of rats. Moreover, preliminary evidence in patients with CKD also suggests that both selective ET(A)- and nonselective ET(A)/ET(B)-receptor blockade decreases blood pressure but that selective ET(A) blockade has additional desirable effects on renal hemodynamics. Thus, at least in CKD, these findings support the notion that ET(B) receptor-mediated actions produce a renoprotective effect and that nonselective ET(A)/ET(B)-receptors blockade seem to offer no advantage over selective ET(A) antagonism, and if anything may potentially reduce the benefits.
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Affiliation(s)
- Mamoru Ohkita
- Laboratory of Pathological and Molecular Pharmacology, Osaka University of Pharmaceutical Sciences, Japan
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Mondillo C, Pagotto RM, Piotrkowski B, Reche CG, Patrignani ZJ, Cymeryng CB, Pignataro OP. Involvement of nitric oxide synthase in the mechanism of histamine-induced inhibition of Leydig cell steroidogenesis via histamine receptor subtypes in Sprague-Dawley rats. Biol Reprod 2008; 80:144-52. [PMID: 18768916 DOI: 10.1095/biolreprod.108.069484] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
This study was conducted to shed light on the so far unexplored intracellular mechanisms underlying negative modulation of Leydig cell steroidogenesis by histamine (HA). Using the MA-10 cell line and highly purified rat Leydig cells as experimental models, we examined the effect of the amine on biochemical steps known to be modulated by HA or involved in LH/hCG action. In agreement with previous findings, HA at 10 microM showed a potent inhibitory effect on hCG-stimulated steroid synthesis, regardless of the gonadotropin concentration used. Moreover, HA decreased not only LH/hCG-induced cAMP production but also steroid synthesis stimulated by the permeable cAMP analog dibutyryl cAMP (db-cAMP). Considering the post-cAMP sites of HA action, it is shown herein that HA markedly inhibited db-cAMP-stimulated steroidogenic acute regulatory (STAR) protein expression, as well as steps catalyzed by P450-dependent enzymes, mainly the conversion of cholesterol to pregnenolone by cholesterol side-chain cleavage enzyme (CYP11A). The antisteroidogenic action of HA was blocked by addition of the phospholipase C (PLC) inhibitor U73122, and HA significantly augmented inositol triphosphate (IP3) production, suggesting a major role for the PLC/IP3 pathway in HA-induced inhibition of Leydig cell function. Finally, HA increased nitric oxide synthase (NOS) activity, and the NOS inhibitor NG-nitro-L-arginine methyl ester (L-NAME) markedly attenuated the effect of the amine on steroid synthesis. On the basis of our findings, HA antagonizes the gonadotropin action in Leydig cells at steps before and after cAMP formation. NOS activation is the main intracellular mechanism by which HA exerts its antisteroidogenic effects.
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Affiliation(s)
- Carolina Mondillo
- Laboratory of Molecular Endocrinology and Signal Transduction, Institute of Biology and Experimental Medicine-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), CP 1428, Buenos Aires, Argentina.
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Hope SI, Schmipp J, Rossi AH, Bianciotti LG, Vatta MS. Regulation of the neuronal norepinephrine transporter by endothelin-1 and -3 in the rat anterior and posterior hypothalamus. Neurochem Int 2008; 53:207-13. [PMID: 18682267 DOI: 10.1016/j.neuint.2008.07.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2008] [Revised: 05/27/2008] [Accepted: 07/10/2008] [Indexed: 11/18/2022]
Abstract
We previously reported that endothelin-1 and endothelin-3 modulate norepinephrine neuronal release and tyrosine hydroxylase activity and expression in the hypothalamus. In the present study we sought to establish the role of endothelin-1 and -3 in the regulation of norepinephrine uptake in the anterior and posterior hypothalamus. Results showed that in the anterior hypothalamus endothelin-3 increased neuronal norepinephrine uptake whereas endothelin-1 decreased it. Conversely, in the posterior hypothalamic region both endothelins diminished the neuronal uptake of the amine. Endothelins response was concentration dependent and maintained at all studied times. Endothelins also modified the kinetic and internalization of the NE neuronal transporter. In the anterior hypothalamic region endothelin-3 increased the V(max) and the B(max) whereas endothelin-1 decreased them. However, in the posterior hypothalamic region both endothelins diminished the V(max) as well as B(max). Neither endothelin-1 nor endothelin-3 modified neuronal norepinephrine transporter K(d) in the studied hypothalamic regions. These findings support that in the posterior hypothalamic region both endothelins diminished neuronal norepinephrine transporter activity by reducing the amine transporter expression on the plasmatic membrane. Conversely, in the anterior hypothalamic region endothelin-3 enhanced neuronal norepinephrine transporter activity by increasing the expression of the transporter on the presynaptic membrane, whereas endothelin-1 induced the opposite effect. Present results permit us to conclude that both endothelins play an important role in the regulation of norepinephrine neurotransmission at the presynaptic nerve endings in the hypothalamus.
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Affiliation(s)
- Sandra I Hope
- Cátedra de Fisiología e Instituto de Química y Metabolismo del Fármaco, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina
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Perfume G, Nabhen SL, Riquelme Barrera K, Otero MG, Bianciotti LG, Vatta MS. Long-term modulation of tyrosine hydroxylase activity and expression by endothelin-1 and -3 in the rat anterior and posterior hypothalamus. Am J Physiol Regul Integr Comp Physiol 2008; 294:R905-14. [DOI: 10.1152/ajpregu.00555.2007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Brain catecholamines are involved in the regulation of biological functions, including cardiovascular activity. The hypothalamus presents areas with high density of catecholaminergic neurons and the endothelin system. Two hypothalamic regions intimately related with the cardiovascular control are distinguished: the anterior (AHR) and posterior (PHR) hypothalamus, considered to be sympathoinhibitory and sympathoexcitatory regions, respectively. We previously reported that endothelins (ETs) are involved in the short-term tyrosine hydroxylase (TH) regulation in both the AHR and PHR. TH is crucial for catecholaminergic transmission and is tightly regulated by well-characterized mechanisms. In the present study, we sought to establish the effects and underlying mechanisms of ET-1 and ET-3 on TH long-term modulation. Results showed that in the AHR, ETs decreased TH activity through ETBreceptor activation coupled to the nitric oxide, phosphoinositide, and CaMK-II pathways. They also reduced total TH level and TH phosphorylated forms (Ser 19 and 40). Conversely, in the PHR, ETs increased TH activity through a G protein-coupled receptor, likely an atypical ET receptor or the ETCreceptor, which stimulated the phosphoinositide and adenylyl cyclase pathways, as well as CaMK-II. ETs also increased total TH level and the Ser 19, 31, and 40 phosphorylated sites of the enzyme. These findings support that ETs are involved in the long-term regulation of TH activity, leading to reduced sympathoinhibition in the AHR and increased sympathoexcitation in the PHR. Present and previous studies may partially explain the cardiovascular effects produced by ETs when applied to the brain.
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Endothelin and NOS1/nitric oxide signaling and regulation of sodium homeostasis. Curr Opin Nephrol Hypertens 2008; 17:70-5. [PMID: 18090673 DOI: 10.1097/mnh.0b013e3282f34b02] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW In general, the nitric oxide and endothelin signaling pathways in the kidney promote natriuresis. The basis for this statement will first be reviewed for each of these systems. Next, this review will outline the progression of data providing support for our hypothesis that an intra-renal mechanism of endothelin activation of ETB receptors stimulates NOS1 activity and nitric oxide production to promote sodium excretion. RECENT FINDINGS New information in recent years has provided considerable evidence that both nitric oxide and endothelin function to regulate sodium and water balance by the kidney. Furthermore, dysfunction of these pathways may play a role in salt-sensitivity and hypertension. While a strong picture has emerged to suggest these systems are important and powerful players in sodium homeostasis, many questions remain to be answered before we can apply these mechanisms to an understanding of clinical hypertension. SUMMARY Salt-sensitive hypertension contributes to the growing population of patients resistant to conventional antihypertensive therapy. Thus, a thorough understanding of the mechanisms related to the control of sodium excretion will allow a more focused approach for future therapeutic studies.
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Xu D, Tang Y, Liu S, Liu J. Expression and significance of endothelin 1 in spiral ganglion cells of guinea pig. Int J Pediatr Otorhinolaryngol 2008; 72:189-92. [PMID: 18022701 DOI: 10.1016/j.ijporl.2007.10.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2005] [Revised: 10/03/2007] [Accepted: 10/04/2007] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Endothelin 1 has many biological activities including actions in the nervous system. This study aimed to investigate the expression of the endothelin 1 in spiral ganglion cells of guinea pig and its significance in the auditory transmission. METHODS Healthy guinea pigs were sacrificed and cardiac perfused with saline followed by 4% paraformaldehyde. Temporal bones were removed and fixed, decalcified in 10% EDTA, embedded in paraffin block and serially sectioned in 5 microm thick slice. Rabbit anti-endothelin 1 polyclonal antibody was used as primary antibody to examine the expression of endothelin 1 in the spiral ganglion by immunohistochemistry. RESULTS Endothelin 1 expression was detected in spiral ganglion cells from the basal turn to the apical turn of the cochlea. CONCLUSIONS The endothelin 1 presents in spiral ganglions cells of the guinea pig and might play a role in the auditory transmission.
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Affiliation(s)
- Dingyuan Xu
- Department of Otorhinolaryngology, West China Hospital of Sichuan University, Chengdu 610041, China
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Perfume G, Morgazo C, Nabhen S, Batistone A, Hope SI, Bianciotti LG, Vatta MS. Short-term regulation of tyrosine hydroxylase activity and expression by endothelin-1 and endothelin-3 in the rat posterior hypothalamus. ACTA ACUST UNITED AC 2007; 142:69-77. [PMID: 17363078 DOI: 10.1016/j.regpep.2007.01.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2006] [Revised: 12/28/2006] [Accepted: 01/31/2007] [Indexed: 12/20/2022]
Abstract
Brain catecholamines are involved in several biological functions regulated by the hypothalamus. We have previously reported that endothelin-1 and -3 (ET-1 and ET-3) modulate norepinephrine release in the anterior and posterior hypothalamus. As tyrosine hydroxylase (TH) is the rate-limiting enzyme in catecholamine biosynthesis, the aim of the present work was to investigate the effects of ET-1 and ET-3 on TH activity, total enzyme level and the phosphorylated forms of TH in the rat posterior hypothalamus. Results showed that ET-1 and ET-3 diminished TH activity but the response was abolished by both selective ET(A) and ET(B) antagonists (BQ-610 and BQ-788, respectively). In addition ET(A) and ET(B) selective agonists (sarafotoxin S6b and IRL-1620, respectively) failed to affect TH activity. In order to investigate the intracellular signaling coupled to endothelins (ETs) response, nitric oxide (NO), phosphoinositide, cAMP/PKA and CaMK-II pathways were studied. Results showed that N(omega)-nitro-l-arginine methyl ester and 7-nitroindazole (NO synthase and neuronal NO synthase inhibitors, respectively), 1H-[1,2,4]-oxadiazolo[4,3-alpha]quinozalin-1-one and KT-5823 (soluble guanylyl cyclase, and PKG inhibitors, respectively) inhibited ETs effect on TH activity. Further, sodium nitroprusside and 8-bromoguanosine-3',5'-cyclic monophosphate (NO donor and cGMP analog, respectively) mimicked ETs response. ETs-induced reduction of TH activity was not affected by a PKA inhibitor but it was abolished by PLC, PKC and CaMK-II inhibitors as well as by an IP(3) receptor antagonist. On the other hand, both ETs did not modify TH total level but reduced the phosphorylation of serine residues of the enzyme at positions 19, 31 and 40. Present results suggest that ET-1 and ET-3 diminished TH activity through an atypical ET or ET(C) receptor coupled to the NO/cGMP/PKG, phosphoinositide and CaMK-II pathways. Furthermore, TH diminished activity may result from the reduction of the phosphorylated sites of the enzyme without changes in its total level. Taken jointly present and previous results support that ET-1 and ET-3 may play a relevant role in the modulation of catecholaminergic neurotransmission in the posterior hypothalamus of the rat.
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Affiliation(s)
- Guadalupe Perfume
- Cátedra de Fisiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina
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Mathison Y, del Garrido MR, Israel A. Multiple signaling pathways involved in the effect of endothelin type B receptor in rat median eminence. ACTA BIOLOGICA HUNGARICA 2007; 58:139-50. [PMID: 17585504 DOI: 10.1556/abiol.58.2007.2.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We assessed the possible link between endothelin receptor mediated phosphoinositide breakdown and NO/cGMP signaling pathways in rat arcuate nucleus-median eminence fragments (AN-ME), brain structures known to contain a rich plexus of nitric oxide synthase (NOS)-containing neurons and fibers, together with densely arranged endothelin ETB-receptors-like immunoreactive fibres. Our data show that ET-1, ET-3 and the ETB-receptors agonist, IRL 1620, increased inositol monophosphate (InsP1) accumulation, NOS activity and cGMP formation, in a similar degree. The stimulatory effect of ETs on InsP1 accumulation and cGMP formation was inhibited by the phospholipase C (PLC) inhibitor, neomycin, and the absence of extracellular calcium, suggesting that calcium is involved in endothelin receptor-induced PLC activation. The L-arginine analog, L-NAME, inhibited ET-1 or IRL1620-stimulated cGMP formation. The ETA receptor antagonists BQ 123, did not alter, while the ETB receptor antagonists BQ788 inhibited ETs-induced increase in the PI metabolism, NOS activity and cGMP generation. Our data indicate that in AN-ME, ETB receptor signals through receptor-mediated calcium dependent-stimulation of phosphoinositide breakdown and activation of NOS/cGMP signaling pathway.
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Affiliation(s)
- Yaira Mathison
- School of Medicine José María Vargas, Universidad Central de Venezuela, Caracas, Venezuela
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Xu Y, Krukoff TL. Adrenomedullin stimulates nitric oxide production from primary rat hypothalamic neurons: roles of calcium and phosphatases. Mol Pharmacol 2007; 72:112-20. [PMID: 17446268 DOI: 10.1124/mol.106.033761] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Adrenomedullin (ADM) in the brain plays important roles in the maintenance of homeostasis. Although in vivo evidence has suggested that nitric oxide (NO) mediates ADM's effects in the brain, mechanisms for ADM stimulation of NO production in neurons have not been identified. In the present study, primary hypothalamic neurons were used to characterize ADM-induced NO production and to study the underlying mechanisms. Using Calcium Orange/4-amino-5-methylamino-2',7'-difluorofluorescein fluorescence live cell imaging, we found that ADM (1 or 10 nM, 5 min) significantly elevated [Ca(2+)](i) and NO production in a concentration-dependent manner. Ca(2+) and NO responses induced by 10 nM ADM were abolished by pretreatment with 50 microM 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester (BAPTA-AM), an intracellular Ca(2+) chelator, or protein kinase A (PKA) inhibitors 5 microM N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide dihydrochloride (H-89) and 50 microM Rp-cAMP. Furthermore, the ADM-induced NO production was significantly attenuated by a protein phosphatase 1/2A inhibitor, okadaic acid (OA; 0.1 microM), or calcineurin inhibitors, tacrolimus (FK506) (1 microM) and cyclosporin A (CsA; 0.1 microM). Using Western blotting, we found that ADM significantly decreased phosphorylation of neuronal nitric-oxide synthase (nNOS) at serine 847. This dephosphorylation was inhibited by 0.1 microM OA, 1 microM FK506, 0.1 microM CsA, or 5 microM H-89, and attenuated by 50 microM BAPTA-AM. These results suggest that, in hypothalamic neurons, ADM elevates [Ca(2+)](i) via PKA-associated mechanisms. The PKA/Ca(2+) cascade leads to protein phosphatase (PP) 1/PP2A- and calcineurin-mediated dephosphorylation of nNOS. We hypothesize that the Ca(2+) increase and nNOS dephosphorylation contribute to activation of nNOS and production of NO in hypothalamic neurons.
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Affiliation(s)
- Yong Xu
- Department of Cell Biology, Center for Neuroscience, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada T6G 2H7
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Tang L, Luo B, Patel RP, Ling Y, Zhang J, Fallon MB. Modulation of pulmonary endothelial endothelin B receptor expression and signaling: implications for experimental hepatopulmonary syndrome. Am J Physiol Lung Cell Mol Physiol 2007; 292:L1467-72. [PMID: 17337507 PMCID: PMC2825024 DOI: 10.1152/ajplung.00446.2006] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The hepatopulmonary syndrome (HPS) results from intrapulmonary vasodilation in the setting of cirrhosis and portal hypertension. In experimental HPS, pulmonary endothelial endothelin B (ET(B)) receptor overexpression and increased circulating endothelin-1 (ET-1) contribute to vasodilation through enhanced endothelial nitric oxide synthase (eNOS)-derived nitric oxide (NO) production. In both experimental cirrhosis and prehepatic portal hypertension, ET(B) receptor overexpression correlates with increased vascular shear stress, a known modulator of ET(B) receptor expression. We investigated the mechanisms of pulmonary endothelial ET(B) receptor-mediated eNOS activation by ET-1 in vitro and in vivo. The effect of shear stress on ET(B) receptor expression was assessed in rat pulmonary microvascular endothelial cells (RPMVECs). The consequences of ET(B) receptor overexpression on ET-1-dependent ET(B) receptor-mediated eNOS activation were evaluated in RPMVECs and in prehepatic portal hypertensive animals exposed to exogenous ET-1. Laminar shear stress increased ET(B) receptor expression in RPMVECs without altering mRNA stability. Both shear-mediated and targeted overexpression of the ET(B) receptor enhanced ET-1-mediated ET(B) receptor-dependent eNOS activation in RPMVECs through Ca(2+)-mediated signaling pathways and independent of Akt activation. In prehepatic portal hypertensive animals relative to control, ET-1 administration also activated eNOS independent of Akt activation and triggered HPS. These findings support that increased pulmonary microvascular endothelial ET(B) receptor expression modulates ET-1-mediated eNOS activation, independent of Akt, and contributes to the development of HPS.
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Affiliation(s)
- Liping Tang
- Department of Internal Medicine and Liver Center, University of Alabama at Birmingham, Birmingham, Alabama 35294-0005, USA
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Morgazo C, Perfume G, Legaz G, di Nunzio A, Hope SI, Bianciotti LG, Vatta MS. Involvement of nitric oxide pathways in short term modulation of tyrosine hydroxylase activity by endothelins 1 and 3 in the rat anterior hypothalamus. Biochem Biophys Res Commun 2006; 334:796-802. [PMID: 16023617 DOI: 10.1016/j.bbrc.2005.06.168] [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: 05/30/2005] [Accepted: 06/28/2005] [Indexed: 11/24/2022]
Abstract
The ability of endothelins 1 and 3 (ET-1 and ET-3) to reduce neuronal norepinephrine release through ETB receptor activation involving nitric oxide (NO) pathways in the rat anterior hypothalamus region (AHR) was previously reported. In the present work, we studied the effects of ET-1 and -3 on tyrosine hydroxylase (TH) activity and the possible involvement of NO pathways. Results showed that ET-1 and -3 (10 nM) diminished TH activity in AHR and this effect was blocked by a selective ETB receptor antagonist (100 nM BQ-788), but not by a ET(A) receptor antagonist (BQ-610). To confirm these results, 1 microM IRL-1620 (ET(B) agonist) reduced TH activity whereas 300 nM sarafotoxin S6b falled to modify it. N(omega)-Nitro-L-arginine methyl ester (10 microM), 7-nitroindazole (10 microM), 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-ona (10 microM), KT5823 (2 microM), inhibitors of nitric oxide synthase, neuronal nitric oxide synthase, NO-sensitive-guanylyl cyclase, and protein kinase G, respectively, did not modify the reduction of TH activity produced by ETs. In addition, both 100 microM sodium nitroprusside and 50 microM 8-bromoguanosine-3',5'-cyclic monophosphate (NO donor and guanosine-3',5'-cyclic monophosphate analog, respectively) diminished TH activity. Present results showed that ET-1 and ET-3 diminished TH activity through the activation of ET(B) receptors involving the NO/guanosine-3',5'-cyclic monophosphate/protein kinase G pathway. Taken jointly present and previous results it can be concluded that both ETs play an important role as modulators of norepinephrine neurotransmission in the rat AHR.
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Affiliation(s)
- Carolina Morgazo
- Cátedra de Fisiología e Instituto de Química y Metabolismo del Fármaco (IQUIMEFA-CONICET), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina
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Fabricio ASC, Tringali G, Pozzoli G, Melo MC, Vercesi JA, Souza GEP, Navarra P. Interleukin-1 mediates endothelin-1-induced fever and prostaglandin production in the preoptic area of rats. Am J Physiol Regul Integr Comp Physiol 2006; 290:R1515-23. [PMID: 16455768 DOI: 10.1152/ajpregu.00604.2005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The intracerebroventricular injection of endothelin-1 (ET-1) induces fever and increases PG levels in the cerebrospinal fluid of rats. Likewise, the injection of IL-1 into the preoptic area (POA) of the rat hypothalamus causes both fever and increased PG production. In this study, we conducted in vivo and in vitro experiments in the rat to investigate 1) the hypothalamic region involved in ET-1-induced fever and PG biosynthesis and 2) whether hypothalamic IL-1 plays a role as a mediator of the above ET-1 activities. One hundred femtomoles of ET-1 increased body temperature when injected in the POA of conscious Wistar rats; this effect was significantly counteracted by the coinjection of 600 pmol IL-1 receptor antagonist (IL-1ra). In experiments on rat hypothalamic explants, 100 nM ET-1 caused a significant increase in PGE2 production and release from the whole hypothalamus and from the isolated POA, but not from the retrochiasmatic region, in 1-h incubations. Six nanomoles of IL-1ra or 10 nM of a cell-permeable interleukin-1 converting enzyme inhibitor completely counteracted the effect of ET-1 on PGE2 release from the POA. One hundred nanomoles ET-1 also caused a significant increase in IL-1beta immunoreactivity released into the bath solution of hypothalamic explants after 1 h of incubation, although during such time ET-1 failed to modify the gene expression of IL-1beta and other pyrogenic cytokines within the hypothalamus. In conclusion, our results show that ET-1 increases IL-1 production in the POA, and this effect appears to be correlated to ET-1-induced fever in vivo, as well as to PG production in vitro.
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Affiliation(s)
- Aline S C Fabricio
- Institute of Pharmacology, Catholic University Medical School, Largo F. Vito 1 - 00168 Rome, Italy
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Stricklett PK, Hughes AK, Kohan DE. Endothelin-1 stimulates NO production and inhibits cAMP accumulation in rat inner medullary collecting duct through independent pathways. Am J Physiol Renal Physiol 2005; 290:F1315-9. [PMID: 16380457 DOI: 10.1152/ajprenal.00450.2005] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Endothelin-1 (ET-1) inhibition of vasopressin (AVP)-stimulated cAMP accumulation in the collecting duct has been hypothesized to be mediated, at least in part, by nitric oxide (NO). To examine this, the effect of ET-1 on NO production by acutely isolated rat inner medullary collecting duct (IMCD) cell suspensions and the role of NO in mediating ET-1 effects on AVP-stimulated cAMP accumulation were studied. ET-1 dose dependently (first evident at 100 pM ET-1) increased IMCD NO production as determined by DAF-FM fluorescence. ET(B) receptor (BQ-788), but not ET(A) receptor (BQ-123), antagonism blocked this effect. Nonspecific NO synthase (NOS) inhibitors [N(G)-nitro-L-arginine methyl ester (L-NAME) or N(G)-monomethyl-L-arginine] or NOS-1 inhibitors (SMTC or VNIO) inhibited the ET-1 response, whereas NOS-2 or NOS-3 inhibitors (L-NAA or 1400W) were ineffective. ET-1 also increased cGMP accumulation. ET-1 caused a 35% reduction in AVP-stimulated cAMP levels; however, this response was not affected by L-NAME or SMTC. The addition of L-arginine, NADPH, tetrahydrobiopterin, or tempol (to reduce superoxide-dependent conversion of NO to peroxynitrate) did not affect the response. NO donors (SNAP or spermine NONOate), at concentrations that stimulated DAF-FM fluorescence and increased cGMP levels, did not alter AVP-stimulated cAMP accumulation in the IMCD cell suspensions. In conclusion, ET-1 stimulates IMCD NO production through activation of the ET(B) receptor and NOS-1. However, neither ET-1-mediated NO production nor NO donors inhibit AVP-stimulated cAMP accumulation, indicating that NO does not mediate ET-1 inhibition of cAMP production by the IMCD.
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Affiliation(s)
- Peter K Stricklett
- Division of Nephrology, Univ. of Utah Health Sciences Center, 1900 East, 30 North, Salt Lake City, UT 84132, USA
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Rodríguez MR, Sabbatini ME, Santella G, Dabas P, Villagra A, Vatta MS, Bianciotti LG. Endothelin-3 applied to the brain evokes opposite effects on bile secretion mediated by a central nitric oxide pathway. Peptides 2005; 26:1219-27. [PMID: 15949640 DOI: 10.1016/j.peptides.2005.02.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2004] [Revised: 01/27/2005] [Accepted: 02/01/2005] [Indexed: 11/22/2022]
Abstract
We sought to establish Endothelin (ET-3) role in the central regulation of bile secretion in the rat. The intracerebroventricular (icv) injection of ET-3 evoked a cholestatic or a choleretic effect depending on the administered dose. Lower doses increased bile flow and bicarbonate excretion, whereas higher doses decreased bile flow and bile acid output. ET-3 effects were dependent on brain nitric oxide and independent of the autonomic nervous system or hemodynamic variations. A selective ETB antagonist abolished the cholestatic effect, whereas the choleretic effect was totally inhibited by either ETA or ETB selective blockade. These results show that ET-3 applied to the brain modified through a nitric oxide pathway distinct bile flow fractions depending on the administered dose and give further insights into the complexity of brain-liver interaction.
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Affiliation(s)
- Myrian R Rodríguez
- Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, 1113 Buenos Aires, Argentina
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