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Henze D, Menzel M, Soukup J, Scharf A, Holz C, Németh N, Hanisch F, Clausen T. Endothelin-1 and cerebral blood flow in a porcine model. J Clin Neurosci 2007; 14:650-7. [PMID: 17532501 DOI: 10.1016/j.jocn.2006.05.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Accepted: 05/30/2006] [Indexed: 11/28/2022]
Abstract
The purpose of the study was to investigate whether provoked changes of cerebral perfusion pressure and arterial carbon dioxide tension are able to influence the cerebral metabolism of endothelin-1 (ET-1) in a porcine model. Brain tissue oxygen tension, regional cerebral blood flow and mean arterial blood pressure were monitored in 10 healthy pigs during induced hyperventilation (HV), hypertension (HrT) and hypotension (HoT). ET-1 was determined in the arterial and cerebrovenous blood. Microdialysis samples (lactate, glucose and pyruvate) were taken from brain and subcutaneous tissue. A significant decrease (p<0.05) of the arterial ET-1 (1.46+/-0.33 fmol/mL) compared to the baseline (2.18+/-0.36 fmol/mL) was observed after the HoT-period. We detected a positive correlation between cerebrovenous ET-1 and extracellular cerebral glucose (0.68; p<0.05) after the baseline as well as a negative correlation of -0.81 (p<0.005) between the cerebrovenous ET-1 level and the extracellular cerebral lactate after the HoT-period. These data imply that with increasingly pathological changes of the cerebral metabolism endothelin becomes progressively more important in the regulation of cerebral vascular tone.
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Affiliation(s)
- Dirk Henze
- Department of Anaesthesiology and Intensive Care Medicine, Martin-Luther-University Halle-Wittenberg, Dryanderstr. 4-7, 06108 Halle (Saale), Germany.
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Beck C, Schwarte LA, Schindler AW, Scheeren TWL, Picker O. Endogenous nitric oxide reduces the efficacy of the endothelin system to maintain blood pressure during high epidural anaesthesia in conscious dogs. Eur J Anaesthesiol 2007; 24:689-96. [PMID: 17437657 DOI: 10.1017/s0265021507000142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND OBJECTIVE During high epidural anaesthesia, endothelin only contributes minimally to blood pressure stabilization. This phenomenon could result from the inhibitory action of nitric oxide on the endothelin system. To clarify this, we studied the interaction between nitric oxide and endothelin during high epidural anaesthesia in conscious dogs, in comparison to the interaction of nitric oxide and vasopressin. METHODS Six animals were used in 45 individual experiments randomly arranged as follows: N-omega-nitro-arginine-methylester 0.3-10 mg kg-1 under physiological conditions or during high epidural anaesthesia (lidocaine 1%) and N-omega-nitro-arginine-methylester (l-NAME) 0.3-10 mg kg-1 after preceding endothelin (Tezosentan(R)) or vasopressin (beta-mercapto-beta,beta-cyclo-penta-methylene-propionyl-O-Me-Tyr-Arg-vasopressin) receptor blockade under physiological conditions or during high epidural anaesthesia. During control experiments normal saline was injected either intravenously (n = 5) or into the epidural space (n = 4). RESULTS N-omega-nitro-arginine-methylester increased mean arterial pressure dose-dependently in all groups. However, this effect was substantially reduced in the presence of the endothelin receptor antagonist compared to N-omega-nitro-arginine-methylester alone, both under control conditions (7 +/- 3 vs. 21 +/- 3 mmHg; P < 0.05) and during high epidural anaesthesia (17 +/- 3 vs. 30 +/- 1 mmHg; P < 0.05). Blockade of vasopressin showed no similar relationship with N-omega-nitro-arginine-methylester. CONCLUSIONS The diminished increase in mean arterial pressure after injection of N-omega-nitro-arginine-methylester only during endothelin receptor blockade indicates that endogenous nitric oxide inhibits the action of endothelin during high epidural anaesthesia and might thus explain the reduced efficacy of endothelin in maintaining blood pressure during high epidural anaesthesia.
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Affiliation(s)
- C Beck
- University Hospital of Duesseldorf, Department of Anaesthesiology, Germany
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Picker O, Schwarte LA, Roth HJ, Greve J, Scheeren TWL. Comparison of the role of endothelin, vasopressin and angiotensin in arterial pressure regulation during sevoflurane anaesthesia in dogs. Br J Anaesth 2004; 92:102-8. [PMID: 14665561 DOI: 10.1093/bja/aeh025] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND In this study we aimed to clarify the role of endothelin in arterial pressure regulation during anaesthesia with increasing concentrations of sevoflurane (1-3 MAC) and compare it with those of vasopressin and angiotensin. METHODS After an awake control period, on different days, six dogs underwent each of the following four interventions: sevoflurane anaesthesia alone (1-3 MAC), sevoflurane after block of either endothelin receptors using tezosentan (3 mg kg(-1) followed by 3 mg kg(-1) h(-1)), vasopressin V(1a) receptors using [d(CH(2))(5)Tyr(Me(2))]AVP (40 micro g kg(--1)) or angiotensin receptors using losartan (6 mg kg(-1) h(-1)). Plasma concentrations of endothelin, big endothelin, vasopressin and renin were measured. Effects of sevoflurane in the presence and absence of the respective receptor block were analysed and compared using analysis of variance for repeated measures (ANOVA followed by Fisher's PLSD (protected least significant difference) (P<0.05)). RESULTS Mean arterial pressure decreased in a dose-dependent manner with sevoflurane during all interventions. At 1 MAC, this decrease was greatest during angiotensin receptor block (mean (SEM), -41 (3) mm Hg), intermediate during vasopressin and endothelin receptor block (-31 (4) and -30 (2) mm Hg respectively), and least during sevoflurane alone (-24 (3) mm Hg). The course of systemic vascular resistance mirrored the course of arterial pressure, while cardiac output did not differ between groups. Plasma concentrations of endothelin, big endothelin and renin did not change during any intervention, whereas vasopressin concentration increased from approximately 0.5 to 40 ng litre(-1) at 3 MAC as arterial pressure decreased in all groups. CONCLUSIONS At 1 MAC, angiotensin attenuated the decrease in arterial pressure during sevoflurane anaesthesia more than endothelin and vasopressin. However, at higher MAC only vasopressin was specifically activated to partly compensate for the arterial pressure decrease.
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Affiliation(s)
- O Picker
- Department of Anaesthesiology, Universitätsklinikum Düsseldorf, Moorenstrasse 5, D-40225 Düsseldorf, Germany.
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Magder S, Cernacek P. Role of endothelins in septic, cardiogenic, and hemorrhagic shock. Can J Physiol Pharmacol 2003; 81:635-43. [PMID: 12839274 DOI: 10.1139/y03-050] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Shock is a condition where blood flow is inadequate for tissue needs. In all forms of shock, the concentrations of endothelins (ETs) are elevated, and they are especially high in septic shock. The rise in ETs plasma levels may initially have some positive homeostatic effects, for ETs can help restore normal vascular tone. However, high levels of ETs compromise the appropriate matching of flow to tissue needs and contribute to the pathophysiology of shock. Attempts at regulating the effects of ETs by the use of pharmacological blockers is made complicated by important interactions between the ETA and ETB receptors and potentially different effects on different tissues. We conclude that antagonism of ET receptors is unlikely to be helpful for cardiogenic or hemorrhagic shock. Furthermore, selective blockade is unlikely to be helpful. However, moderate doses of a mixed ET receptor antagonist may be of use for the management of septic patients.
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Affiliation(s)
- S Magder
- McGill University Health Center, McGill University, Divisions of Critical Care and Clinical Biochemistry, Royal Victoria Hospital, 687 Pine Ave. W., Montreal, QC H3A 1A1, Canada.
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Picker O, Schindler AW, Scheeren TW. Endogenous endothelin and vasopressin support blood pressure during epidural anesthesia in conscious dogs. Anesth Analg 2001; 93:1580-6, table of contents. [PMID: 11726449 DOI: 10.1097/00000539-200112000-00054] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
UNLABELLED We studied whether endogenous endothelin, like endogenous vasopressin, helps to maintain blood pressure during high epidural anesthesia when efferent sympathetic drive is diminished. On different days, six awake dogs underwent each of the following five interventions: blockade of vasopressin V(1a) receptors using [d(CH(2))(5)Tyr(Me(2))]AVP, (40 microg/kg) or endothelin receptors using tezosentan (3 mg/kg followed by 3 mg. kg(-1). h(-1)) with or without epidural anesthesia (1% lidocaine, intraindividual dose did not differ between experiments), and epidural saline (n = 5). The effects of endothelin- or vasopressin-receptor blockade were analyzed (means +/- SEM) and compared by an analysis of variance for repeated measures (paired Student's t-test, alpha-adjusted, P < 0.05). Vasopressin-receptor blockade decreased blood pressure (10 +/- 2 mm Hg) only in the presence of epidural anesthesia, whereas endothelin-receptor blockade reduced blood pressure both in the presence and absence of epidural anesthesia (12 +/- 3 versus 10 +/- 1 mm Hg). During baseline and each intervention, plasma concentrations of vasopressin and big-endothelin were measured and compared by a Wilcoxon's rank sum test; P < 0.05. Vasopressin concentrations increased during epidural anesthesia and after additional endothelin receptor blockade, but big-endothelin concentrations remained unchanged during each intervention. We conclude that vasopressin acts as a reserve system, as it stabilizes blood pressure specifically during epidural anesthesia, whereas the unchanged concentrations of big-endothelin indicate that the endothelin system is not specifically activated to support blood pressure during epidural anesthesia. IMPLICATIONS We studied in awake dogs whether endogenous endothelin, like endogenous vasopressin, helps to maintain blood pressure during resting conditions and epidural anesthesia. Only vasopressin was specifically activated to support blood pressure during epidural anesthesia, whereas endothelin supported blood pressure to the same extent during epidural anesthesia and during resting conditions.
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Affiliation(s)
- O Picker
- Department of Anesthesiology, Heinrich-Heine-University, Duesseldorf, Germany.
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Takamura M, Parent R, Cernacek P, Lavallée M. Influence of dual ET(A)/ET(B)-receptor blockade on coronary responses to treadmill exercise in dogs. J Appl Physiol (1985) 2000; 89:2041-8. [PMID: 11053360 DOI: 10.1152/jappl.2000.89.5.2041] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We hypothesized that endothelin (ET) release during exercise may be triggered by alpha-adrenergic-receptor activation and thereby influence coronary hemodynamics and O(2) metabolism in dogs. Exercise resulted in coronary blood flow increases (to 1.88+/-0.26 from 1.10+/- 0.12 ml x min(-1) x g(-1)) and in a fall (P<0.01) in coronary sinus O(2) saturation (17.4+/-1.5 to 9.6+/-0.7 vol%), whereas myocardial O(2) consumption (MVO(2)) increased (109+/-13% from 145+/-16 microl O(2) min(-1) x g(-1)). Tezosentan, a dual ET(A)/ET(B)-receptor blocker, slightly reduced mean arterial pressure (MAP) and increased heart rate throughout exercise. The relationship between coronary sinus O(2) saturation and MVO(2) was shifted upward (P<0.05) after tezosentan administration; i.e., as MVO(2) increased during exercise, coronary sinus O(2) saturation was disproportionately higher after ET-receptor blockade. After propranolol, tezosentan resulted in significant decreases (P<0.05) in left ventricular pressure, the first derivative of left ventricular pressure over time, and MAP during exercise. As MVO(2) increased during exercise, coronary sinus O(2) saturation levels after tezosentan became superimposable over those observed before ET-receptor blockade. Thus dual blockade of ET(A)/ET(B) receptors alters coronary hemodynamics and O(2) metabolism during exercise, but ET activity failed to increase beyond baseline levels.
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Affiliation(s)
- M Takamura
- Department of Medicine, Institut de Cardiologie de Montréal, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada H1T 1C8
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Cernacek P, Franchi L, Dupuis J, Rouleau JL, Levy M. Radioreceptor assay of an endothelin A receptor antagonist in plasma and urine. Clin Chem 1998. [DOI: 10.1093/clinchem/44.8.1666] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Abstract
Orally active nonpeptide antagonists of endothelin (ET) receptors may prove beneficial in the treatment of cardiovascular and renal disease. The pharmacodynamics and pharmacokinetics of these drugs are not sufficiently known, and practical methods for their analysis have not been developed. We describe a simple, sensitive, and reproducible radioreceptor assay (RRA) for LU135252, a selective antagonist of the ETA receptor, using porcine aortic smooth muscle membranes as the acceptor and 125I-endothelin-1 as the ligand. With methanol extraction of plasma and urine samples, recovery of LU135252 ranged from 79% to 91% at 60–1000 nmol/L. The logit-log transformed calibration curves constructed with LU135252 added to plasma or to urine were linear (r = 0.993 ± 0.005, n = 11) in the range from 18.7 to 2400 nmol/L. The detection limit with plasma- and urine-based calibration curves was 19 nmol/L. The interassay coefficient of variation was 12.6% at 70 nmol/L (n = 9) and 6.5% at 590 nmol/L (n = 9). Endothelin-1 did not interfere in the RRA at pathophysiologically and clinically relevant concentrations [up to 15 pmol/L (40 pg/mL)]. When LU135252 was added to plasma, the signal was completely stable after storage for 1 week at 4 °C, although there was a modest loss of the signal after 24 h at room temperature. The practical performance of this RRA was then tested in plasma samples obtained from (a) rats after a single oral administration of LU135252, (b) from coronary-ligated rats chronically treated with LU135252, and (c) in plasma and urine samples obtained from dogs during intrarenal infusion of LU135252.
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Affiliation(s)
- Peter Cernacek
- Montreal Heart Institute, Department of Laboratory Medicine, 5000 Belanger Street East, Montreal, Quebec, H1T 1C8 Canada
| | - Luigi Franchi
- Departments of Medicine, McGill University, Montreal, Quebec, H1T 1C8 Canada
| | - Jocelyn Dupuis
- Montreal Heart Institute, Department of Laboratory Medicine, 5000 Belanger Street East, Montreal, Quebec, H1T 1C8 Canada
| | - Jean-Lucien Rouleau
- Montreal Heart Institute, Department of Laboratory Medicine, 5000 Belanger Street East, Montreal, Quebec, H1T 1C8 Canada
| | - Mortimer Levy
- Departments of Medicine, McGill University, Montreal, Quebec, H1T 1C8 Canada
- Departments of Physiology, McGill University, Montreal, Quebec, H1T 1C8 Canada
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Martinet JP, Legault L, Cernacek P, Roy L, Dufresne MP, Spahr L, Fenyves D, Pomier-Layrargues G. Changes in plasma endothelin-1 and Big endothelin-1 induced by transjugular intrahepatic portosystemic shunts in patients with cirrhosis and refractory ascites. J Hepatol 1996; 25:700-6. [PMID: 8938548 DOI: 10.1016/s0168-8278(96)80241-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND/AIMS Endothelin-1 (ET-1) is a potent vasoconstrictor that may be involved in the pathogenesis of splanchnic and renal hemodynamic changes associated with portal hypertension. The aim of this study was to measure the concentration of ET-1 and of its precursor Big endothelin-1 (Big ET-1) in the systemic circulation as well as in the splanchnic and renal venous beds and to evaluate changes after the relief of portal hypertension following transjugular intrahepatic portosystemic shunt placement. METHODS Plasma concentrations of ET-1 and of Big ET-1 were measured in the vena cava, renal vein, hepatic vein and portal vein in ten patients with cirrhosis and refractory ascites before and 1-2 months after transjugular intrahepatic portosystemic shunt. The porto-caval gradient, creatinine clearance, plasma aldosterone and renin activity, as well as daily urinary sodium excretion were measured at the same time. RESULTS The plasma concentration of ET-1 and Big ET-1, respectively, in peripheral blood of normal volunteers were 0.28 +/- 03 and 3.95 +/- 0.34 pg/ml; the concentrations of both peptides were higher in patients with cirrhosis, both in vena cava (0.61 +/- 0.14 and 10.01 +/- 1.47 pg/ml), hepatic vein (0.62 +/- 0.13 and 13.93 +/- 1.77 pg/ml), portal vein (1.21 +/- 0.12 and 17.84 +/- 1.98 pg/ml) and renal vein (0.76 +/- 0.12 and 14.21 +/- 1.55 pg/ml). Moreover ET-1 and Big ET-1 concentrations were more elevated in the portal vein than in the vena cava (+98% and +70%) and slightly higher in the renal vein as compared to the vena cava (+25% and +42%). After transjugular intrahepatic portosystemic shunt, a rise in creatinine clearance and urinary sodium excretion (+49%; and +53%) was observed together with a marked reduction in plasma aldosterone and renin activity (-59% and -49%). ET-1 and Big ET-1 concentrations remained unchanged in the vena cava whereas a significant reduction of ET-1 and Big ET-1 occurred both in the portal vein (-43% and -44%) and in the renal vein (-53% and -29%). Portal vein and renal vein concentrations of both peptides became similar to vena cava levels. CONCLUSIONS Splanchnic and renal hemodynamic changes occurring in patients with cirrhosis and refractory ascites could be related to the production of ET-1 by splanchnic and renal vascular beds. This was abolished by transjugular intrahepatic portosystemic shunt, which could explain the exacerbation of systemic vasodilation and the improvement in renal perfusion observed after the procedure.
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Affiliation(s)
- J P Martinet
- Kidney Unit, Saint-Luc Hospital, Montréal, Québec, Canada
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Hinson JP, Kapas S, Cameron LA. Differential effects of endogenous and exogenous nitric oxide on the release of endothelin-1 from the intact perfused rat adrenal gland in situ. FEBS Lett 1996; 379:7-10. [PMID: 8566233 DOI: 10.1016/0014-5793(95)01467-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Studies using an inhibitor of nitric oxide (NO) synthesis have suggested that endogenous NO may have a role in regulating endothelin release. We investigated the effect of endogenous and exogenous nitric oxide (NO) on the release of irET-1. L-NAME stimulated, but L-arginine inhibited irET-1 release. Perfusing sodium nitroprusside (SNP), however, did not inhibit irET-1 secretion. CyclicGMP, the second messenger for NO action, was stimulated by SNP but not by L-arginine. These data demonstrate that endogenous NO inhibits of irET-1, in a manner which is independent of cGMP, and suggest that this action may contribute to the vasodilatory effect of NO.
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Affiliation(s)
- J P Hinson
- Department of Biochemistry, Faculty of Basic Medical Sciences, Queen Mary and Westfield College, London, UK.
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