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Ahmad A, Sattar MA, Rathore HA, Khan SA, Lazhari MI, Afzal S, Hashmi F, Abdullah NA, Johns EJ. A critical review of pharmacological significance of Hydrogen Sulfide in hypertension. Indian J Pharmacol 2016; 47:243-7. [PMID: 26069359 PMCID: PMC4450547 DOI: 10.4103/0253-7613.157106] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 12/08/2013] [Accepted: 04/20/2015] [Indexed: 11/04/2022] Open
Abstract
In the family of gas transmitters, hydrogen sulfide (H2S) is yet not adequately researched. Known for its rotten egg smell and adverse effects on the brain, lungs, and kidneys for more than 300 years, the vasorelaxant effects of H2S on blood vessel was first observed in 1997. Since then, research continued to explore the possible therapeutic effects of H2S in hypertension, inflammation, pancreatitis, different types of shock, diabetes, and heart failure. However, a considerable amount of efforts are yet needed to elucidate the mechanisms involved in the therapeutic effects of H2S, such as nitric oxide-dependent or independent vasodilation in hypertension and regression of left ventricular hypertrophy. More than a decade of good repute among researchers, H2S research has certain results that need to be clarified or reevaluated. H2S produces its response by multiple modes of action, such as opening the ATP-sensitive potassium channel, angiotensin-converting enzyme inhibition, and calcium channel blockade. H2S is endogenously produced from two sulfur-containing amino acids L-cysteine and L-methionine by the two enzymes cystathionine γ lyase and cystathionine β synthase. Recently, the third enzyme, 3-mercaptopyruvate sulfur transferase, along with cysteine aminotransferase, which is similar to aspartate aminotransferase, has been found to produce H2S in the brain. The H2S has interested researchers, and a great deal of information is being generated every year. This review aims to provide an update on the developments in the research of H2S in hypertension amid the ambiguity in defining the exact role of H2S in hypertension because of insufficient number of research results on this area. This critical review on the role of H2S in hypertension will clarify the gray areas and highlight its future prospects.
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Affiliation(s)
- Ashfaq Ahmad
- Department of Physiology, School of Pharmaceutical Sciences, University Sains Malaysia, Penang 11800, Malaysia
| | - Munavvar A Sattar
- Department of Physiology, School of Pharmaceutical Sciences, University Sains Malaysia, Penang 11800, Malaysia
| | - Hassaan A Rathore
- Department of Physiology, School of Pharmaceutical Sciences, University Sains Malaysia, Penang 11800, Malaysia
| | - Safia Akhtar Khan
- Department of Physiology, School of Pharmaceutical Sciences, University Sains Malaysia, Penang 11800, Malaysia
| | - M I Lazhari
- Department of Physiology, School of Pharmaceutical Sciences, University Sains Malaysia, Penang 11800, Malaysia
| | - Sheryar Afzal
- Department of Physiology, School of Pharmaceutical Sciences, University Sains Malaysia, Penang 11800, Malaysia
| | - F Hashmi
- Department of Physiology, School of Pharmaceutical Sciences, University Sains Malaysia, Penang 11800, Malaysia
| | - Nor A Abdullah
- Department of Pharmacology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Edward J Johns
- Department of Physiology, University College Cork, Cork, Ireland
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Torres Filho IP, Torres LN, Pittman RN. Early physiologic responses to hemorrhagic hypotension. Transl Res 2010; 155:78-88. [PMID: 20129488 PMCID: PMC2900811 DOI: 10.1016/j.trsl.2009.09.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2009] [Revised: 08/26/2009] [Accepted: 09/01/2009] [Indexed: 01/08/2023]
Abstract
The identification of early indicators of hemorrhagic hypotension (HH) severity may support early therapeutic approaches and bring insights into possible mechanistic implications. However, few systematic investigations of physiologic variables during early stages of hemorrhage are available. We hypothesized that, in certain subjects, early physiologic responses to blood loss are associated with the ability to survive hemorrhage levels that are lethal to subjects that do not present the same responses. Therefore, we examine the relevance of specific systemic changes during and after the bleeding phase of HH. Stepwise hemorrhage, representing prehospital situations, was performed in 44 rats, and measurements were made after each step. Heart and respiratory rates, arterial and venous blood pressures, gases, acid-base status, glucose, lactate, electrolytes, hemoglobin, O(2) saturation, tidal volume, and minute volume were measured before, during, and after bleeding 40% of the total blood volume. Fifty percent of rats survived 100 min (survivors, S) or longer; others were considered nonsurvivors (NS). Our findings were as follows: (1) S and NS subjected to a similar hemorrhage challenge showed significantly different responses during nonlethal levels of bleeding; (2) survivors showed higher blood pressure and ventilation than NS; (3) although pH was lower in NS at later stages, changes in bicarbonate and base excess occurred already during the hemorrhage phase and were higher in NS; and (4) plasma K(+) levels and glucose extraction were higher in NS. We conclude that cardiorespiratory and metabolic responses, essential for the survival at HH, can differentiate between S and NS even before a lethal bleeding was reached.
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Affiliation(s)
- Ivo P Torres Filho
- Department of Physiology and Biophysic, Virginia Commonwealth University Reanimation Engineering Shock Center (VCURES), Virginia Commonwealth University Health System, Richmond, VA 23298-0551, USA.
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Rocha Filho JA, Nani RS, D'Albuquerque LAC, Holms CA, Rocha JPS, Sá Malbouisson LM, Machado MCC, Carmona MJC, Auler Júnior JOC. Hyperkalemia accompanies hemorrhagic shock and correlates with mortality. Clinics (Sao Paulo) 2009; 64:591-7. [PMID: 19578665 PMCID: PMC2705155 DOI: 10.1590/s1807-59322009000600016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2009] [Accepted: 04/02/2009] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE This study was designed to evaluate the effects of terlipressin versus fluid resuscitation with normal saline, hypertonic saline or hypertonic-hyperoncotic hydroxyethyl starch, on hemodynamics, metabolics, blood loss and short-term survival in hemorrhagic shock. METHOD Twenty-nine pigs were subjected to severe liver injury and treated 30 min later with either: (1) 2 mg terlipressin in a bolus, (2) placebo-treated controls, (3) 4 mL/kg 7.5% hypertonic NaCl, (4) 4 mL/kg 7.2% hypertonic-hyperoncotic hydroxyethyl starch 200/0.5, or (5) normal saline at three times lost blood volume. RESULTS The overall mortality rate was 69%. Blood loss was significantly higher in the hypertonic-hyperoncotic hydroxyethyl starch and normal saline groups than in the terlipressin, hypertonic NaCl and placebo-treated controls groups (p<0.005). Hyperkalemia (K>5 mmol/L) before any treatment occurred in 66% of the patients (80% among non-survivors vs. 22% among survivors, p=0.019). Post-resuscitation hyperkalemia occurred in 86.66% of non-survivors vs. 0% of survivors (p<0.001). Hyperkalemia was the first sign of an unsuccessful outcome for the usual resuscitative procedure and was not related to arterial acidemia. Successfully resuscitated animals showed a significant decrease in serum potassium levels relative to the baseline value. CONCLUSION Hyperkalemia accompanies hemorrhagic shock and, in addition to providing an early sign of the acute ischemic insult severity, may be responsible for cardiac arrest related to hemorrhagic shock.
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Affiliation(s)
- Joel Avancini Rocha Filho
- Department of Anesthesiology, Hospital das Clinicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil.
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Zakaria ER, Li N, Garrison RN. Mechanisms of direct peritoneal resuscitation-mediated splanchnic hyperperfusion following hemorrhagic shock. Shock 2007; 27:436-42. [PMID: 17414428 PMCID: PMC2121218 DOI: 10.1097/01.shk.0000245017.86117.4e] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Conventional resuscitation (CR) from hemorrhagic shock causes a persistent and progressive splanchnic vasoconstriction and hypoperfusion despite hemodynamic restoration with intravenous fluid therapy. Adjunctive direct peritoneal resuscitation (DPR) with a clinical peritoneal dialysis solution instilled into the peritoneal cavity has been shown to restore splanchnic tissue perfusion, down-regulate the gut-derived exaggerated systemic inflammatory response, promote early fluid mobilization, and improve overall outcome. This study was conducted to define the molecular mechanisms of DPR-induced gut hyperperfusion after hemorrhagic shock. Male rats were bled to 50% baseline mean arterial pressure and resuscitated with the shed blood plus two volumes of saline (CR). In vivo videomicroscopy and Doppler velocimetry were used to assess terminal ileal microvascular diameters and blood flow. Direct peritoneal resuscitation animals received CR and topical application of a clinical glucose-based peritoneal dialysis solution (Delflex). Inhibitors, glibenclamide (K(+)ATP channels), N-monomethyl-L-arginine (L-NMMA) (nitric oxide synthase), 8-cyclopentyl-1,3-diprophylxanthine (DPCPX) (A1 adenosine receptor), tetrabutylammonium (K(+)Ca2+ channels), and mefenamic acid (cyclooxygenase) were topically applied (individually or in combination) with DPR according to protocol; BQ-123 (endothelin A receptor antagonist) and BQ-788 (endothelin B receptor antagonist) were used topically with CR to define the mechanism of post-CR vasoconstriction and hypoperfusion. Conventional resuscitation caused a persistent progressive intestinal vasoconstriction and hypoperfusion that can be abolished with endothelin antagonists. In contrast, adjunctive DPR caused an instantaneous sustained vasodilation and hyperperfusion. Glibenclamide or L-NMMA partially attenuated DPR-induced vasodilation, whereas the addition of DPCPX to the two inhibitors eliminated the dilation. Cyclooxygenase and K(+)Ca2+channels were not active in DPR-mediated microvascular effects. In conclusion, DPR improves splanchnic tissue perfusion by endothelium-dependent mechanisms mediated by activations of glibenclamide-sensitive K(+) channels (KATP), adenosine A1 receptor subtype activation, and nitric oxide release. Direct peritoneal resuscitation preserves endothelial dilatory functions, thereby overriding any endothelium-derived constrictor response triggered by hemorrhagic shock and CR.
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Affiliation(s)
- El Rasheid Zakaria
- Department of Physiology, Health Sciences Center , University of Louisville, Kentucky 40292, USA.
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Friesenecker BE, Tsai AG, Martini J, Ulmer H, Wenzel V, Hasibeder WR, Intaglietta M, Dünser MW. Arteriolar vasoconstrictive response: comparing the effects of arginine vasopressin and norepinephrine. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2006; 10:R75. [PMID: 16696866 PMCID: PMC1550934 DOI: 10.1186/cc4922] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2006] [Revised: 04/11/2006] [Accepted: 04/19/2006] [Indexed: 10/26/2022]
Abstract
INTRODUCTION This study was designed to examine differences in the arteriolar vasoconstrictive response between arginine vasopressin (AVP) and norepinephrine (NE) on the microcirculatory level in the hamster window chamber model in unanesthetized, normotonic hamsters using intravital microscopy. It is known from patients with advanced vasodilatory shock that AVP exerts strong additional vasoconstriction when incremental dosage increases of NE have no further effect on mean arterial blood pressure (MAP). METHODS In a prospective controlled experimental study, eleven awake, male golden Syrian hamsters were instrumented with a viewing window inserted into the dorsal skinfold. NE (2 microg/kg/minute) and AVP (0.0001 IU/kg/minute, equivalent to 4 IU/h in a 70 kg patient) were continuously infused to achieve a similar increase in MAP. According to their position within the arteriolar network, arterioles were grouped into five types: A0 (branch off small artery) to A4 (branch off A3 arteriole). RESULTS Reduction of arteriolar diameter (NE, -31 +/- 12% versus AVP, -49 +/- 7%; p = 0.002), cross sectional area (NE, -49 +/- 17% versus AVP, -73 +/- 7%; p = 0.002), and arteriolar blood flow (NE, -62 +/- 13% versus AVP, -80 +/- 6%; p = 0.004) in A0 arterioles was significantly more pronounced in AVP animals. There was no difference in red blood cell velocities in A0 arterioles between groups. The reduction of diameter, cross sectional area, red blood cell velocity, and arteriolar blood flow in A1 to A4 arterioles was comparable in AVP and NE animals. CONCLUSION Within the microvascular network, AVP exerted significantly stronger vasoconstriction on large A0 arterioles than NE under physiological conditions. This observation may partly explain why AVP is such a potent vasopressor hormone and can increase systemic vascular resistance even in advanced vasodilatory shock unresponsive to increases in standard catecholamine therapy.
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Affiliation(s)
- Barbara E Friesenecker
- Division of General and Surgical Intensive Care Medicine, Department of Anesthesiology and Critical Care Medicine, Innsbruck Medical University, Innsbruck, Austria
| | - Amy G Tsai
- Department of Bioengineering, University of California, San Diego, CA, USA
| | - Judith Martini
- Department of Bioengineering, University of California, San Diego, CA, USA
| | - Hanno Ulmer
- Institute of Biostatistics and Documentation, Medical University Innsbruck, Innsbruck, Austria
| | - Volker Wenzel
- Division of Anesthesiology, Department of Anesthesiology and Critical Care Medicine, Innsbruck Medical University, Innsbruck, Austria
| | - Walter R Hasibeder
- Department of Anesthesiology and Critical Care Medicine, Krankenhaus der Barmherzigen Schwestern, Ried im Innkreis, Austria
| | - Marcos Intaglietta
- Department of Bioengineering, University of California, San Diego, CA, USA
| | - Martin W Dünser
- Department of Intensive Care Medicine, University Hospital of Bern, Bern, Switzerland
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Cao C, Lee-Kwon W, Silldorff EP, Pallone TL. KATP channel conductance of descending vasa recta pericytes. Am J Physiol Renal Physiol 2005; 289:F1235-45. [PMID: 16048905 DOI: 10.1152/ajprenal.00111.2005] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Using nystatin-perforated patch-clamp and whole cell recording, we tested the hypothesis that K(ATP) channels contribute to resting conductance of rat descending vasa recta (DVR) pericytes and are modulated by vasoconstrictors. The K(ATP) blocker glybenclamide (Glb; 10 microM) depolarized pericytes and inhibited outward currents of cells held at -40 mV. K(ATP) openers pinacidil (Pnc; 10 microM) and P-1075 (1 microM) hyperpolarized pericytes and transiently augmented outward currents. All effects of Pnc and P-1075 were fully reversed by Glb. Inward currents of pericytes held at -60 mV in symmetrical 140 mM K(+) were markedly augmented by Pnc and fully reversed by Glb. Ramp depolarizations in symmetrical K(+), performed in Pnc and Pnc + Glb, yielded a Pnc-induced, Glb-sensitive K(ATP) difference current that lacked rectification and reversed at 0 mV. Immunostaining identified both K(IR)6.1, K(IR)6.2 inward rectifier subunits and sulfonurea receptor subtype 2B. ANG II (1 and 10 nM) and endothelin-1 (10 nM) but not vasopressin (100 nM) significantly lowered holding current at -40 mV and abolished Pnc-stimulated outward currents. We conclude that DVR pericytes express K(ATP) channels that make a significant contribution to basal K(+) conductance and are inhibited by ANG II and endothelin-1.
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Affiliation(s)
- Chunhua Cao
- Division of Nephrology, Department of Medicine, University of Maryland, Baltimore, 21201, USA
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Mok YYP, Mohammed Atan MSB, Ping CY, Jing WZ, Bhatia M, Moochhala S, Moore PK. Role of hydrogen sulphide in haemorrhagic shock in the rat: protective effect of inhibitors of hydrogen sulphide biosynthesis. Br J Pharmacol 2004; 143:881-9. [PMID: 15504752 PMCID: PMC1575944 DOI: 10.1038/sj.bjp.0706014] [Citation(s) in RCA: 192] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Haemorrhagic shock (60 min) in the anaesthetized rat resulted in a prolonged fall in the mean arterial blood pressure (MAP) and heart rate (HR). Pre-treatment (30 min before shock) or post-treatment (60 min after shock) with inhibitors of cystathionine gamma lyase (CSE; converts cysteine into hydrogen sulphide (H(2)S)), dl-propargylglycine or beta-cyanoalanine (50 mg kg(-1), i.v.), or glibenclamide (40 mg kg(-1), i.p.), produced a rapid, partial restoration in MAP and HR. Neither saline nor DMSO affected MAP or HR. Plasma H(2)S concentration was elevated 60 min after blood withdrawal (37.5+/-1.3 microM, n=18 c.f. 28.9+/-1.4 microM, n=15, P<0.05). The conversion of cysteine to H(2)S by liver (but not kidney) homogenates prepared from animals killed 60 min after withdrawal of blood was significantly increased (52.1+/-1.6 c.f. 39.8+/-4.1 nmol mg protein(-1), n=8, P<0.05), as was liver CSE mRNA (2.7 x). Both PAG (IC(50), 55.0+/-3.2 microM) and BCA (IC(50), 6.5+/-1.2 microM) inhibited liver H(2)S synthesizing activity in vitro. Pre-treatment of animals with PAG or BCA (50 mg kg(-1), i.p.) but not glibenclamide (40 mg kg(-1), i.p., K(ATP) channel inhibitor) abolished the rise in plasma H(2)S in animals exposed to 60 min haemorrhagic shock and prevented the augmented biosynthesis of H(2)S from cysteine in liver. These results demonstrate that H(2)S plays a role in haemorrhagic shock in the rat. CSE inhibitors may provide a novel approach to the treatment of haemorrhagic shock.
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Affiliation(s)
- Ying-Yuan Pamela Mok
- Department of Pharmacology, National University of Singapore, Block MD2, 18 Medical Drive, 117597, Singapore
| | | | - Cheong Yoke Ping
- Department of Pharmacology, National University of Singapore, Block MD2, 18 Medical Drive, 117597, Singapore
| | - Wang Zhong Jing
- Department of Pharmacology, National University of Singapore, Block MD2, 18 Medical Drive, 117597, Singapore
| | - Madhav Bhatia
- Department of Pharmacology, National University of Singapore, Block MD2, 18 Medical Drive, 117597, Singapore
| | - Shabbir Moochhala
- Centre for Biomedical Sciences, DSO National Laboratories, 27 Medical Drive, 117510, Singapore
| | - Philip K Moore
- Department of Pharmacology, National University of Singapore, Block MD2, 18 Medical Drive, 117597, Singapore
- Author for correspondence:
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Asfar P, Iványi Z, Bracht H, Hauser B, Pittner A, Vassilev D, Nalos M, Leverve XM, Brückner UB, Radermacher P, Fröba G. HMR1402, a potassium ATP channel blocker during hyperdynamic porcine endotoxemia: effects on hepato-splanchnic oxygen exchange and metabolism. Intensive Care Med 2004; 30:957-64. [PMID: 15045166 DOI: 10.1007/s00134-004-2258-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2003] [Accepted: 02/25/2004] [Indexed: 10/26/2022]
Abstract
OBJECTIVE To assess the effects of the potassium ATP (KATP) channel blocker HMR1402 (HMR) on systemic and hepato-splanchnic hemodynamics, oxygen exchange and metabolism during hyperdynamic porcine endotoxemia. DESIGN Prospective, randomized, controlled study with repeated measures. SETTING. Animal laboratory. SUBJECTS Eighteen pigs allocated to receive endotoxin alone (control group, CON, n=10) or endotoxin and HMR (6 mg/kg h(-1), n=8). INTERVENTIONS Anesthetized, mechanically ventilated, and instrumented pigs receiving continuous i.v. endotoxin were resuscitated with hetastarch to maintain mean arterial pressure (MAP) >60 mmHg. Twelve hours after starting the endotoxin infusion, they received HMR or its vehicle for another 12 h. RESULTS HMR transiently increased MAP by about 15 mmHg, but this effect was only present during the first 1 h of infusion. The HMR decreased cardiac output due to a fall in heart rate, and thereby reduced liver blood flow. While liver O(2) delivery and uptake remained unchanged, HMR induced hyperlactatemia [from 1.5 (1.1; 2.0), 1.4 (1.2; 1.8), and 1.2 (0.8; 2.0) to 3.1 (1.4; 3.2), 3.2 (1.6; 6.5), and 3.0 (1.0; 5.5) mmol/l in the arterial, portal and hepatic venous samples, respectively] and further increased arterial [from 8 (3; 13) to 23 (11; 57); p<0.05], portal [from 9 (4; 14) to 23 (14; 39); p<0.05] and hepatic vein [from 7 (0; 15) to 30 (8; 174), p<0.05] lactate/pyruvate ratios indicating impaired cytosolic redox state. CONCLUSION The short-term beneficial hemodynamic effects of KATP channel blockers have to be weighted with the detrimental effect on mitochondrial respiration.
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Affiliation(s)
- Pierre Asfar
- Sektion Anästhesiologische Pathophysiologie und Verfahrensentwicklung, Parkstrasse 11, 89073 Ulm, Germany
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Holmes CL, Landry DW, Granton JT. Science Review: Vasopressin and the cardiovascular system part 2 - clinical physiology. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2003; 8:15-23. [PMID: 14975041 PMCID: PMC420051 DOI: 10.1186/cc2338] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Vasopressin is emerging as a rational therapy for vasodilatory shock states. In part 1 of the review we discussed the structure and function of the various vasopressin receptors. In part 2 we discuss vascular smooth muscle contraction pathways with an emphasis on the effects of vasopressin on ATP-sensitive K+ channels, nitric oxide pathways, and interaction with adrenergic agents. We explore the complex and contradictory studies of vasopressin on cardiac inotropy and coronary vascular tone. Finally, we summarize the clinical studies of vasopressin in shock states, which to date have been relatively small and have focused on physiologic outcomes. Because of potential adverse effects of vasopressin, clinical use of vasopressin in vasodilatory shock should await a randomized controlled trial of the effect of vasopressin's effect on outcomes such as organ failure and mortality.
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Affiliation(s)
- Cheryl L Holmes
- Staff intensivist, Department of Medicine, Division of Critical Care, Kelowna General Hospital, Kelowna BC, Canada
| | - Donald W Landry
- Associate Professor, Department of Medicine, Columbia University, New York, New York, USA
| | - John T Granton
- Assistant Professor of Medicine, Faculty of Medicine, and Program Director, Critical Care Medicine, University of Toronto, and Consultant in Pulmonary and Critical Care Medicine, Director Pulmonary Hypertension Program, University Health Network, Toronto, Ontario, Canada
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Abstract
Ion channels exist in all cells and are enormously varied in structure, function and regulation. Some progress has been made in understanding the role that ion channels play in the control of blood pressure, but the discipline is still in its infancy. Ion channels provide many different targets for intervention in disorders of blood pressure and exciting advances have been made in this field. It is possible that new drugs, as well as antisense nucleotide technology or gene therapy directed towards ion channels, may form a new class of treatments for high and low blood pressure in the future.
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Affiliation(s)
- E H Baker
- Department of Pharmacology and Clinical Pharmacology, St George's Hospital Medical School, London, UK.
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Morales D, Madigan J, Cullinane S, Chen J, Heath M, Oz M, Oliver JA, Landry DW. Reversal by vasopressin of intractable hypotension in the late phase of hemorrhagic shock. Circulation 1999; 100:226-9. [PMID: 10411844 DOI: 10.1161/01.cir.100.3.226] [Citation(s) in RCA: 173] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Hypovolemic shock of marked severity and duration may progress to cardiovascular collapse unresponsive to volume replacement and drug intervention. On the basis of clinical observations, we investigated the action of vasopressin in an animal model of this condition. METHODS AND RESULTS In 7 dogs, prolonged hemorrhagic shock (mean arterial pressure [MAP] of approximately 40 mm Hg) was induced by exsanguination into a reservoir. After approximately 30 minutes, progressive reinfusion was needed to maintain MAP at approximately 40 mm Hg, and by approximately 1 hour, despite complete restoration of blood volume, the administration of norepinephrine approximately 3 micrograms . kg(-1). min(-1) was required to maintain this pressure. At this moment, administration of vasopressin 1 to 4 mU. kg(-1). min(-1) increased MAP from 39+/-6 to 128+/-9 mm Hg (P<0.001), primarily because of peripheral vasoconstriction. In 3 dogs subjected to similar prolonged hemorrhagic shock, angiotensin II 180 ng. kg(-1). min(-1) had only a marginal effect on MAP (45+/-12 to 49+/-15 mm Hg). Plasma vasopressin was markedly elevated during acute hemorrhage but fell from 319+/-66 to 29+/-9 pg/mL before administration of vasopressin (P<0.01). CONCLUSIONS Vasopressin is a uniquely effective pressor in the irreversible phase of hemorrhagic shock unresponsive to volume replacement and catecholamine vasopressors. Vasopressin deficiency may contribute to the pathogenesis of this condition.
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Affiliation(s)
- D Morales
- Departments of Medicine, Surgery, and Anesthesiology, Columbia University College of Physicians and Surgeons, 630 W 168th St, New York, NY 10032, USA
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