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Zatz R, De Nucci G. Endothelium-Derived Dopamine and 6-Nitrodopamine in the Cardiovascular System. Physiology (Bethesda) 2024; 39:44-59. [PMID: 37874898 PMCID: PMC11283902 DOI: 10.1152/physiol.00020.2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/09/2023] [Accepted: 10/20/2023] [Indexed: 10/26/2023] Open
Abstract
The review deals with the release of endothelium-derived dopamine and 6-nitrodopamine (6-ND) and its effects on isolated vascular tissues and isolated hearts. Basal release of both dopamine and 6-ND is present in human isolated umbilical cord vessels, human popliteal vessels, nonhuman primate vessels, and reptilia aortas. The 6-ND basal release was significantly reduced when the tissues were treated with Nω-nitro-l-arginine methyl ester and virtually abolished when the endothelium was mechanically removed. 6-Nitrodopamine is a potent vasodilator, and the mechanism of action responsible for this effect is the antagonism of dopamine D2-like receptors. As a vasodilator, 6-ND constitutes a novel mechanism by which nitric oxide modulates vascular tone. The basal release of 6-ND was substantially decreased in endothelial nitric oxide synthase knockout (eNOS-/-) mice and not altered in neuronal nitric oxide synthase knockout (nNOS-/-) mice, indicating a nonneurogenic source for 6-ND in the heart. Indeed, in rat isolated right atrium, the release of 6-ND was not affected when the atria were treated with tetrodotoxin. In the rat isolated right atrium, 6-ND is the most potent endogenous positive chronotropic agent, and in Langendorff's heart preparation, it is the most potent endogenous positive inotropic agent. The positive chronotropic and inotropic effects of 6-ND are antagonized by β1-adrenoceptor antagonists at concentrations that do not affect the effects induced by noradrenaline, adrenaline, and dopamine, indicating that blockade of the 6-ND receptor is the major modulator of heart chronotropism and inotropism. The review proposes that endothelium-derived catecholamines may constitute a major mechanism for control of vascular tone and heart functions, in contrast to the overrated role attributed to the autonomic nervous system.
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Affiliation(s)
- Roberto Zatz
- Renal Division, Department of Clinical Medicine, Faculty of Medicine, University of São Paulo, São Paulo, Brazil
| | - Gilberto De Nucci
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
- Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo (ICB-USP), São Paulo, Brazil
- Department of Pharmacology, Faculty of Medicine, São Leopoldo Mandic, Campinas, São Paulo, Brazil
- Department of Pharmacology, Faculty of Medicine, Metropolitan University of Santos, Santos, São Paulo, Brazil
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Britto-Júnior J, Fernandes Jacintho F, Campos R, Pinheiro DHA, Figueiredo Murari GM, de Souza VB, Schenka AA, Mónica FZ, Moreno RA, Antunes E, De Nucci G. The basal release of endothelium-derived catecholamines regulates the contractions of Chelonoidis carbonaria aorta caused by electrical-field stimulation. Biol Open 2021; 10:bio.057042. [PMID: 33277238 PMCID: PMC7847266 DOI: 10.1242/bio.057042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The contractions of Chelonoidis carbonaria aortic rings induced by electrical field stimulation (EFS) are not inhibited by blockade of the voltage-gated sodium channels by tetrodotoxin but almost abolished by the α1/α2-adrenoceptor antagonist phentolamine. The objective of this study was to identify the mediator(s) responsible for the EFS-induced contractions of Chelonoidis carbonaria aortic rings. Each ring was suspended between two wire hooks and mounted in isolated 10 ml organ chambers filled with oxygenated and heated Krebs-Henseleit's solution. Dopamine, noradrenaline and adrenaline concentrations were analysed by liquid chromatography coupled to tandem mass spectrometry. The contractions caused by dopamine and EFS were done in absence and presence of the nitric oxide (NO) synthesis inhibitor L-NAME, the NO-sensitive guanylyl cyclase inhibitor ODQ, the D1-like receptor antagonist SCH-23390, the D2-like receptor antagonists risperidone, quetiapine, haloperidol, and the tyrosine hydroxylase inhibitors salsolinol and 3-iodo-L-tyrosine. Basal concentrations of dopamine, noradrenaline and adrenaline were detected in Krebs-Henseleit solution containing the aortic rings. The catecholamine concentrations were significantly reduced in endothelium-denuded aortic rings. L-NAME and ODQ significantly potentiated the dopamine-induced contractions. The D2-like receptor antagonists inhibited the EFS-induced contractions of the aortic rings treated with L-NAME, whereas SCH 23390 had no effect. Similar results were observed in the contractions induced by dopamine in L-NAME treated aortic rings. These results indicate that catecholamines released by endothelium regulate the EFS-induced contractions. This may constitute a suitable mechanism by which reptilia modulate specific organ blood flow distribution. This paper has an associated First Person interview with the first author of the article. Summary:Chelonoidis carbonaria aortic rings release endothelium-derived catecholamines that modulate vascular smooth muscle reactivity.
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Affiliation(s)
- José Britto-Júnior
- Faculty of Medical Sciences, Department of Pharmacology, University of Campinas (UNICAMP), Campinas 13083-894, Brazil
| | - Felipe Fernandes Jacintho
- Faculty of Medical Sciences, Department of Pharmacology, University of Campinas (UNICAMP), Campinas 13083-894, Brazil
| | - Rafael Campos
- Department of Physiology, Superior Institute of Biomedical Sciences, Ceará State University (UECE), Fortaleza 60714-903, Brazil
| | - David Halen Araújo Pinheiro
- Faculty of Medical Sciences, Department of Pharmacology, University of Campinas (UNICAMP), Campinas 13083-894, Brazil
| | - Guilherme M Figueiredo Murari
- Faculty of Medical Sciences, Department of Pharmacology, University of Campinas (UNICAMP), Campinas 13083-894, Brazil
| | - Valéria B de Souza
- Faculty of Medical Sciences, Department of Pharmacology, University of Campinas (UNICAMP), Campinas 13083-894, Brazil
| | - André A Schenka
- Faculty of Medical Sciences, Department of Pharmacology, University of Campinas (UNICAMP), Campinas 13083-894, Brazil
| | - Fabíola Z Mónica
- Faculty of Medical Sciences, Department of Pharmacology, University of Campinas (UNICAMP), Campinas 13083-894, Brazil
| | - Ronilson Agnaldo Moreno
- Faculty of Medical Sciences, Department of Pharmacology, University of Campinas (UNICAMP), Campinas 13083-894, Brazil
| | - Edson Antunes
- Faculty of Medical Sciences, Department of Pharmacology, University of Campinas (UNICAMP), Campinas 13083-894, Brazil
| | - Gilberto De Nucci
- Faculty of Medical Sciences, Department of Pharmacology, University of Campinas (UNICAMP), Campinas 13083-894, Brazil.,Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-060, Brazil
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Nygaard S, Christensen AH, Rolid K, Nytrøen K, Gullestad L, Fiane A, Thaulow E, Døhlen G, Godang K, Saul JP, Wyller VBB. Autonomic cardiovascular control changes in recent heart transplant recipients lead to physiological limitations in response to orthostatic challenge and isometric exercise. Eur J Appl Physiol 2019; 119:2225-2236. [PMID: 31407088 PMCID: PMC6763412 DOI: 10.1007/s00421-019-04207-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Accepted: 08/06/2019] [Indexed: 12/27/2022]
Abstract
PURPOSE Heart transplantation causes denervation of the donor heart, but the consequences for cardiovascular homeostasis remain to be fully understood. The present study investigated cardiovascular autonomic control at supine rest, during orthostatic challenge and during isometric exercise in heart transplant recipients (HTxR). METHODS A total of 50 HTxRs were investigated 7-12 weeks after transplant surgery and compared with 50 healthy control subjects. Continuous, noninvasive recordings of cardiovascular variables were carried out at supine rest, during 15 min of 60° head-up tilt and during 1 min of 30% of maximal voluntary handgrip. Plasma and urine catecholamines were assayed, and symptoms were charted. RESULTS At supine rest, heart rate, blood pressures and total peripheral resistance were higher, and stroke volume and end diastolic volume were lower in the HTxR group. During tilt, heart rate, blood pressures and total peripheral resistance increased less, and stroke volume and end diastolic volume decreased less. During handgrip, heart rate and cardiac output increased less, and stroke volume and end diastolic volume decreased less. Orthostatic symptoms were similar across the groups, but the HTxRs complained more of pale and cold hands. CONCLUSION HTxRs are characterized by elevated blood pressures and total peripheral resistance at supine rest as well as attenuated blood pressures and total peripheral resistance responses during orthostatic challenge, possibly caused by low-pressure cardiopulmonary baroreceptor denervation. In addition, HTxRs show attenuated cardiac output response during isometric exercise due to efferent sympathetic denervation. These physiological limitations might have negative functional consequences.
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Affiliation(s)
- Sissel Nygaard
- Department of Pediatric Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway.,Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Anders Haugom Christensen
- Department of Pediatric Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway.,Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Katrine Rolid
- Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Kari Nytrøen
- Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Lars Gullestad
- Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway.,KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway.,Center for Heart Failure Research, Oslo University Hospital, Oslo, Norway
| | - Arnt Fiane
- Department of Cardiothoracic Surgery, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Erik Thaulow
- Department of Pediatric Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Gaute Døhlen
- Department of Pediatric Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Kristin Godang
- Section of Specialized Endocrinology, Department of Endocrinology, Oslo University Hospital, Oslo, Norway
| | - J Philip Saul
- Department of Pediatrics, West Virginia University, Morgantown, USA
| | - Vegard Bruun Bratholm Wyller
- Faculty of Medicine, University of Oslo, Oslo, Norway. .,Department of Paediatrics, Akershus University Hospital, 1478, Lørenskog, Norway.
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Zawadka-Kunikowska M, Słomko J, Tafil-Klawe M, Klawe JJ, Cudnoch-Jędrzejewska A, Newton JL, Zalewski P. Role of peripheral vascular resistance as an indicator of cardiovascular abnormalities in patients with Parkinson's disease. Clin Exp Pharmacol Physiol 2017; 44:1089-1098. [PMID: 28681408 DOI: 10.1111/1440-1681.12809] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 06/21/2017] [Accepted: 06/22/2017] [Indexed: 11/26/2022]
Abstract
The aim of this study was to evaluate cardiovascular autonomic modulation in response to an orthostatic stress in healthy subjects and Parkinson's disease (PD). The study included 47 controls and 56 PD patients divided into groups (vasoconstrictor PD, vasodilator PD, control) according to vasodilation/vasoconstriction response during 70° head up tilt test. Using impedance cardiography (ICG) and electrocardiography (ECG) we measured stroke volume, cardiac output, left ventricular work index, left ventricular ejection time, acceleration index, index of contractility, Heather index, thoracic fluid content, total peripheral resistance, total arterial compliance. We also analyzed heart rate variability (HRV), using spectral analysis and continuous blood pressure (contBP). At rest, the vasodilator PD group showed significantly higher values of total peripheral resistance and lower values of stroke volume and cardiac output, compared to the vasoconstrictor PD and the control groups. A post-tilt drop in ∆ (change rest - tilt) systolic blood pressure, ∆mean blood pressure, ∆total peripheral resistance and ∆Heather index, and a significantly lower increase in ∆diastolic blood pressure was observed in subjects from the vasodilator PD group compared to the vasoconstrictor PD and the control groups. No statistically significant differences were observed for HRV parameters between the vasoconstrictor and vasodilator PD groups, P > .05. Longer duration and higher disease stage of PD correlated with a reduction in post-tilt systolic blood pressure changes in vasodilator group. Positive inotropy of the cardiac muscle represents a significant factor preventing orthostatic hypotension in PD subjects with a concurrent drop in peripheral vascular resistance during orthostatic stress.
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Affiliation(s)
- Monika Zawadka-Kunikowska
- Department of Hygiene, Epidemiology and Ergonomy, Faculty of Health Sciences, Ludwik Rydygier Collegium Medicum in Bydgoszcz Nicolaus Copernicus University in Torun, Bydgoszcz, Poland
| | - Joanna Słomko
- Department of Hygiene, Epidemiology and Ergonomy, Faculty of Health Sciences, Ludwik Rydygier Collegium Medicum in Bydgoszcz Nicolaus Copernicus University in Torun, Bydgoszcz, Poland
| | - Małgorzata Tafil-Klawe
- Department of Human Physiology, Faculty of Medicine, Ludwik Rydygier Collegium Medicum in Bydgoszcz Nicolaus Copernicus University in Torun, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Bydgoszcz, Poland
| | - Jacek J Klawe
- Department of Hygiene, Epidemiology and Ergonomy, Faculty of Health Sciences, Ludwik Rydygier Collegium Medicum in Bydgoszcz Nicolaus Copernicus University in Torun, Bydgoszcz, Poland
| | - Agnieszka Cudnoch-Jędrzejewska
- Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
| | - Julia L Newton
- Institute of Cellular Medicine, The Medical School, Newcastle University, Newcastle-upon-Tyne, UK
| | - Paweł Zalewski
- Department of Hygiene, Epidemiology and Ergonomy, Faculty of Health Sciences, Ludwik Rydygier Collegium Medicum in Bydgoszcz Nicolaus Copernicus University in Torun, Bydgoszcz, Poland
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Awad M, Czer LSC, Hou M, Golshani SS, Goltche M, De Robertis M, Kittleson M, Patel J, Azarbal B, Kransdorf E, Esmailian F, Trento A, Kobashigawa JA. Early Denervation and Later Reinnervation of the Heart Following Cardiac Transplantation: A Review. J Am Heart Assoc 2016; 5:JAHA.116.004070. [PMID: 27802930 PMCID: PMC5210323 DOI: 10.1161/jaha.116.004070] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Morcos Awad
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Lawrence S C Czer
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Margaret Hou
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Sarah S Golshani
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Michael Goltche
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | | | - Michelle Kittleson
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Jignesh Patel
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Babak Azarbal
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Evan Kransdorf
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Fardad Esmailian
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Alfredo Trento
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Jon A Kobashigawa
- Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA
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6
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Nakamura T, Hirayama M, Hara T, Mizutani Y, Suzuki J, Watanabe H, Sobue G. Role of cardiac sympathetic nerves in preventing orthostatic hypotension in Parkinson's disease. Parkinsonism Relat Disord 2014; 20:409-14. [PMID: 24462345 DOI: 10.1016/j.parkreldis.2014.01.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 12/22/2013] [Accepted: 01/04/2014] [Indexed: 01/15/2023]
Abstract
PURPOSE Cardiac sympathetic denervation is associated with orthostatic hypotension (OH) in Parkinson's disease (PD); however, the physiological role of cardiac sympathetic nerves has yet to be elucidated. To clarify the role of the heart in orthostatic stress, we evaluated whether cardiac sympathetic nerves can alter cardiac activity and systolic blood pressure (BP) in association with elevations or depressions of total peripheral resistance during the head-up tilt test. METHODS Ninety-five PD patients and 17 normal controls were enrolled. Using impedance cardiography, we measured total peripheral resistance, stroke volume, heart rate, and systolic BP during the head-up tilt test. Cardiac denervation was defined as a heart-to-mediastinum ratio <1.7 for cardiac (123)I-metaiodobenzylguanidine uptake on delayed images. RESULTS At 60° tilt, total peripheral resistance decreased from the initial value in 49 PD patients. Among these, 36 patients exhibited cardiac denervation with severe reductions in systolic BP but little change in stroke volume; among these patients 22 had OH. The remaining 13 patients without cardiac denervation exhibited significant increases in stroke volume and well-preserved systolic BP with no OH. On the other hand, 46 patients had elevations in total peripheral resistance and reduced stroke volume, but little change in systolic BP, regardless of the presence or absence of cardiac denervation. Only one of these patients experienced OH. CONCLUSION Under orthostatic stress, cardiac sympathetic denervation with failure to increase total peripheral resistance leads to large reductions in systolic BP. However, patients without cardiac denervation exhibited a positive inotropic response against vasodilatation, which may prevent OH.
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Affiliation(s)
- Tomohiko Nakamura
- Department of Neurology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan; Department of Laboratory Medicine, Nagoya University Hospital, Nagoya, Japan
| | - Masaaki Hirayama
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Takashi Hara
- Department of Neurology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan; Department of Neurology, Chutoen General Medical Center, Shizuoka, Japan
| | - Yasuaki Mizutani
- Department of Neurology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Junichiro Suzuki
- Department of Neurology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Hirohisa Watanabe
- Department of Neurology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Gen Sobue
- Department of Neurology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
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Fortrat JO, Lemarie C, Bellard E, Victor J. Do we need a reflex tachycardia to stand up? PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2005; 28:962-7. [PMID: 16176536 DOI: 10.1111/j.1540-8159.2005.00216.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Sophisticated atrio-ventricular pacing models are designed to integrate the pacemaker into cardiovascular autonomic control to react appropriately to the cardiovascular demands. Such an approach might be beneficial for patients with vasovagal responses to counterbalance the upright fall in arterial blood pressure by a pacing rate increase. We hypothesized that this approach would improve the cardiovascular response to standing in comparison with a regular pacing mode. METHODS Two 5-minute tilt tests were performed in a random order in 5 patients with a pacemaker (CLS-INOS(2)) for sinus node disease and atrio-ventricular block. One tilt test was performed in fixed pacing rate (DDD), the other one was performed in close loop stimulation (CLS), which allowed an upright rate-rise pacing. Heart rate, systolic blood pressure, and cardiac output (modelflow) were recorded on a beat-by-beat basis. RESULTS Changes of systolic blood pressure and cardiac output in response to upright posture were not significantly different between DDD and CLS modes (2.7 +/- 13.2 vs 10.1 +/- 12.9 mmHg and -0.8 +/- 0.3 vs -1.1 +/- 0.4 L/min, respectively). But upright posture led to a tachycardia of more than 30 bpm in 3 patients in CLS mode and to a fall in systolic blood pressure greater than 20 mmHg in 3 patients in CLS mode and only in one patient in DDD mode. CONCLUSION Systolic blood pressure and cardiac output are not improved by the upright tachycardia and upright blood pressure response is actually worsened when an upright rate-rise pacing is used. Thus, it appears that tachycardia alone cannot compensate for an upright fall in blood pressure.
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Affiliation(s)
- Jacques-Olivier Fortrat
- Laboratoire de Physiologie, Faculté de Médecine, Centre Hospitalo-Universitaire, Faculté de Médecine, 49045 Angers Cedex, France.
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Weisbrod CJ, Arnolda LF, McKitrick DJ, O'Driscoll G, Potter K, Green DJ. Vasomotor responses to decreased venous return: effects of cardiac deafferentation in humans. J Physiol 2004; 560:919-27. [PMID: 15331679 PMCID: PMC1665271 DOI: 10.1113/jphysiol.2004.069732] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
We compared haemodynamic and peripheral vasomotor responses to lower body negative pressure (LBNP) in cardiac transplant recipients who had undergone bicaval anastomoses, involving right atrial deafferentation (-RA), and the conventional procedure in which some atrial baroreceptor afferents remain intact (+RA). We measured mean forearm blood flow (FBF) responses using Doppler/ultrasound during three randomised trials involving 0 (baseline), -20 and -40 mmHg LBNP in 15 transplant recipients (9 -RA, 6 +RA) and in eight healthy matched controls. A significant effect of LBNP on FBF existed between control and transplant groups (P < 0.05; two-way ANOVA). Mild LBNP (-20 mmHg), significantly decreased FBF by 29.7 +/- 10.0% relative to baseline in +RA subjects (P < 0.05), whereas the 17.7 +/- 10.3% decrease in -RA subjects was not significant. In response to -40 mmHg LBNP, FBF significantly decreased in control (42.4 +/- 4.6%, P < 0.05) and +RA subjects (33.3 +/- 11.4%, P < 0.05) with no significant change in the -RA group. The response of systolic blood pressure (SBP) to -40 mmHg significantly differed between groups (P < 0.05): -RA subjects decreased significantly (P < 0.05) whilst the decrease in SBP in +RA subjects did not achieve significance and control subjects exhibited an increase. The heart rate increase from baseline to -40 mmHg was significantly attenuated in -RA relative to controls and the +RA group (P < 0.05). The present study demonstrates that atrial deafferentation impairs reflex vasomotor control of the circulation in response to low- and high-level LBNP, indicating that atrial deafferentation may contribute to abnormal arterial pressure regulation.
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Affiliation(s)
- Cara J Weisbrod
- School of Human Movement and Exercise Science, University of Western Australia, Perth, Australia 6009
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9
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Shoemaker JK, Hogeman CS, Khan M, Kimmerly DS, Sinoway LI. Gender affects sympathetic and hemodynamic response to postural stress. Am J Physiol Heart Circ Physiol 2001; 281:H2028-35. [PMID: 11668064 DOI: 10.1152/ajpheart.2001.281.5.h2028] [Citation(s) in RCA: 172] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We tested the hypothesis that differences in sympathetic reflex responses to head-up tilt (HUT) between males (n = 9) and females (n = 8) were associated with decrements in postural vasomotor responses in women. Muscle sympathetic nerve activity (MSNA; microneurography), heart rate, stroke volume (SV; Doppler), and blood pressure (Finapres) were measured during a progressive HUT protocol (5 min at each of supine, 20 degrees, 40 degrees, and 60 degrees ). MSNA and hemodynamic responses were also measured during the cold pressor test (CPT) to examine nonbaroreflex neurovascular control. SV was normalized to body surface area (SV(i)) to calculate the index of cardiac output (Q(i)), and total peripheral resistance (TPR). During HUT, heart rate increased more in females versus males (P < 0.001) and SV(i) and Q(i) decreased similarly in both groups. Mean arterial pressure (MAP) increased to a lesser extent in females versus males in the HUT (P < 0.01) but increases in TPR during HUT were similar. MSNA burst frequency was lower in females versus males in supine (P < 0.03) but increased similarly during HUT. Average amplitude/burst increased in 60 degrees HUT for males but not females. Both males and females demonstrated an increase in MAP as well as MSNA burst frequency, mean burst amplitude, and total MSNA during the CPT. However, compared with females, males demonstrated a greater neural response (DeltaTotal MSNA) due to a larger increase in mean burst amplitude (P < 0.05). Therefore, these data point to gender-specific autonomic responses to cardiovascular stress. The different MSNA response to postural stress between genders may contribute importantly to decrements in blood pressure control during HUT in females.
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Affiliation(s)
- J K Shoemaker
- Neurovascular Research Laboratory, School of Kinesiology, University of Western Ontario, London, Ontario, Canada, N6A 3K7.
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10
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Takahashi T, Kakita A, Sakamoto I, Takahashi Y, Hayashi K, Tadokoro F, Yamashina S. Immunohistochemical and electron microscopic study of extrinsic hepatic reinnervation following orthotopic liver transplantation in rats. LIVER 2001; 21:300-8. [PMID: 11589766 DOI: 10.1034/j.1600-0676.2001.210502.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND/AIMS Because little has been known about the morphological and functional consequences of liver transplantation on hepatic autonomic nerves, we examined the time-course of extrinsic hepatic innervation at the level of the porta hepatis of liver allografts. METHODS Orthotopic liver transplantation was performed using male Lewis rats. Crosscut tissue specimens were obtained postoperatively for up to 6 months from the porta hepatis of transplanted livers, and processed for immunohistochemical staining for protein gene product 9.5 (PGP 9.5) and growth-associated protein 43 (GAP-43), and for transmission electron microscopy (TEM). RESULTS Extrinsic nerve fibers at the porta hepatis stained positively for PGP 9.5 throughout the entire study period. In contrast, the immunoreactivity of GAP-43 was negative at postoperative day (POD) 1 and 2. GAP-43-positive nerves were first observed to appear in the porta hepatis at POD 3. The immunoreactivity of GAP-43 remained positive thereafter until 3 months post-OLT, and became negative in all the specimens at 4 months post-OLT. Transmission electron microscopy demonstrated a small number of regenerating axons existing among many degenerating axons at POD 3. At 3 months post-OLT, most regenerating axons had been fully ensheathed by the cytoplasm of Schwann cells, although their density remained at a lower level compared with normal. CONCLUSION The results of this study suggest that liver allografts become extrinsically reinnervated, with the regenerating axons reaching the hepatic hilus 3 days after transplantation. The process of extrinsic hepatic reinnervation is considered to almost terminate 4 months after transplantation in rats.
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Affiliation(s)
- T Takahashi
- Department of Surgery, Kitasato University School of Medicine, Kanagawa, Japan.
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11
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Doering LV, Dracup K, Moser DK, Czer LS, Peter CT. Evidence of time-dependent autonomic reinnervation after heart transplantation. Nurs Res 1999; 48:308-16. [PMID: 10571498 DOI: 10.1097/00006199-199911000-00006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Confirming the clinical significance of reinnervation is important in understanding and anticipating how heart rate (HR) responses of transplant recipients to physiologic stress differs early and late after transplant from that of normal individuals. OBJECTIVES To evaluate the functional significance of cardiac reinnervation early and late after heart transplantation. METHODS Handgrip and deep breathing tests, passive 80 degrees head-up tilt, and heart rate (HR) responsiveness of 33 transplant recipients (n = 16 at < 5 months and n = 17 at > 1 year after transplant) were compared with those of 16 age- and sex-matched control participants. RESULTS HR responses to handgrip and passive tilt were absent early after transplant. HR acceleration normalized but was blunted late after transplant. These findings are consistent with late (>1 year) sympathetic reinnervation in transplant recipients. CONCLUSIONS When caring for transplant recipients, nurses should consider the time elapsed since transplant in evaluating HR responsiveness to common procedures and interventions.
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Affiliation(s)
- L V Doering
- UCLA School of Nursing, Los Angeles, CA 90095-6918, USA
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Smit AA, Halliwill JR, Low PA, Wieling W. Pathophysiological basis of orthostatic hypotension in autonomic failure. J Physiol 1999; 519 Pt 1:1-10. [PMID: 10432334 PMCID: PMC2269496 DOI: 10.1111/j.1469-7793.1999.0001o.x] [Citation(s) in RCA: 225] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/1998] [Accepted: 06/16/1999] [Indexed: 11/30/2022] Open
Abstract
In patients with autonomic failure orthostatic hypotension results from an impaired capacity to increase vascular resistance during standing. This fundamental defect leads to increased downward pooling of venous blood and a consequent reduction in stroke volume and cardiac output that exaggerates the orthostatic fall in blood pressure. The location of excessive venous blood pooling has not been established so far, but present data suggest that the abdominal compartment and perhaps leg skin vasculature are the most likely candidates. To improve the orthostatic tolerance in patients with autonomic failure, protective measures that reduce excessive orthostatic blood pooling have been developed and evaluated. These measures include physical counter-manoeuvres and abdominal compression.
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Affiliation(s)
- A A Smit
- Department of Internal Medicine, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
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Cooke WH, Hoag JB, Crossman AA, Kuusela TA, Tahvanainen KU, Eckberg DL. Human responses to upright tilt: a window on central autonomic integration. J Physiol 1999; 517 ( Pt 2):617-28. [PMID: 10332107 PMCID: PMC2269357 DOI: 10.1111/j.1469-7793.1999.0617t.x] [Citation(s) in RCA: 344] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/1998] [Accepted: 03/04/1999] [Indexed: 11/30/2022] Open
Abstract
1. We examined interactions between haemodynamic and autonomic neural oscillations during passive upright tilt, to gain better insight into human autonomic regulatory mechanisms. 2. We recorded the electrocardiogram, finger photoplethysmographic arterial pressure, respiration and peroneal nerve muscle sympathetic activity in nine healthy young adults. Subjects breathed in time with a metronome at 12 breaths min-1 (0.2 Hz) for 5 min each, in supine, and 20, 40, 60, 70 and 80 deg head-up positions. We performed fast Fourier transform (and autoregressive) power spectral analyses and integrated low-frequency (0.05-0.15 Hz) and respiratory-frequency (0. 15-0.5 Hz) spectral powers. 3. Integrated areas of muscle sympathetic bursts and their low- and respiratory-frequency spectral powers increased directly and significantly with the tilt angle. The centre frequency of low-frequency sympathetic oscillations was constant before and during tilt. Sympathetic bursts occurred more commonly during expiration than inspiration at low tilt angles, but occurred equally in expiration and inspiration at high tilt angles. 4. Systolic and diastolic pressures and their low- and respiratory-frequency spectral powers increased, and R-R intervals and their respiratory-frequency spectral power decreased progressively with the tilt angle. Low-frequency R-R interval spectral power did not change. 5. The cross-spectral phase angle between systolic pressures and R-R intervals remained constant and consistently negative at the low frequency, but shifted progressively from positive to negative at the respiratory frequency during tilt. The arterial baroreflex modulus, calculated from low-frequency cross-spectra, decreased at high tilt angles. 6. Our results document changes of baroreflex responses during upright tilt, which may reflect leftward movement of subjects on their arterial pressure sympathetic and vagal response relations. The intensity, but not the centre frequency of low-frequency cardiovascular rhythms, is modulated by the level of arterial baroreceptor input. Tilt reduces respiratory gating of sympathetic and vagal motoneurone responsiveness to stimulatory inputs for different reasons; during tilt, sympathetic stimulation increases to a level that overwhelms the respiratory gate, and vagal stimulation decreases to a level below that necessary for maximal respiratory gating to occur.
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Affiliation(s)
- W H Cooke
- Department of Medicine and Physiology, Hunter Holmes McGuire Department of Veterans Affairs Medical Center and Medical College of Virginia at Virginia Commonwealth University, Richmond, VA 23249, USA.
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Stanford SC, Mikhail G, Salmon P, Gettins D, Zielinski S, Pepper JR. Psychological stress does not affect plasma catecholamines in subjects with cardiovascular disorder. Pharmacol Biochem Behav 1997; 58:1167-74. [PMID: 9408229 DOI: 10.1016/s0091-3057(97)00335-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Whereas the effects of cardiac transplantation on the catecholamine response to physical exercise have been studied previously, the impact on psychological stress is unknown. Here, the arterial catecholamine response to the Stroop test of patients with an orthotopic heart transplant (OHT) was compared with that in subjects who had received a coronary artery bypass graft (CABG) or who were in heart failure and destined for a heart transplant (HF). Subjects were tested whilst sitting and their usual drug therapy was maintained. The Stroop test increased subjects' subjective tension but did not affect arterial concentrations of adrenaline or noradrenaline in any group of subjects. Also, the concentration of both catecholamines was significantly higher in OHT and CABG subjects than in the HF group, but their relative concentration was unaffected by cardiovascular status or stress. It is concluded that the absolute concentrations of arterial catecholamines, but not their relative concentrations, depend on clinical status. Moreover, under these test conditions, subjects with a history of cardiovascular disorder do not show the normal catecholamine response to psychological stress.
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Affiliation(s)
- S C Stanford
- Department of Pharmacology, University College London, UK
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15
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Lord SW, Brady S, Baylis PH, Dark JH, Kenny RA, McComb JM. Vasopressin release during orthostatic hypotension after cardiac transplantation. Clin Auton Res 1996; 6:351-7. [PMID: 8985624 DOI: 10.1007/bf02556306] [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: 02/03/2023]
Abstract
At the time of cardiac transplantation all nerves from the donor ventricles are cut. These nerves may regrow, but there is no method of measuring any regrowth. Arginine vasopressin (AVP) release was studied during hypotension induced by head-up tilt and lower body negative pressure (LBNP) in transplant recipients and in normal controls. Subjects were tilted to 60 degrees for up to 60 min or until symptomatic. Lower body negative pressure (40 mmHg) was applied for 10 min after 30 min rest. Seven of 17 transplant recipients and 11 of 12 controls became symptomatic during tilt testing, and 9 of 12 controls and 9 of 17 transplant recipients became symptomatic after 10 min of LBNP. Symptoms during tilt did not predict symptoms during LBNP. Resting AVP levels were similar but osmolality was greater in transplant recipients. Resting haematocrit was reduced, and atrial natriuretic peptide increased in transplant recipients, suggesting increased plasma volume. In symptomatic subjects, changes in humoral concentrations were similar when compared between transplant recipients and normals, except that the rise in AVP at the time of symptoms was reduced in transplant recipients, with a comparable drop in blood pressure consistent with persistent cardiac afferent denervation in a subset of transplant recipients.
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Affiliation(s)
- S W Lord
- Regional Cardiothoracic Centre, Freeman Hospital, Newcastle upon Tyne, UK
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16
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Doering LV, Dracup K, Moser DK, Czer LS, Peter CT. Hemodynamic adaptation to orthostatic stress after orthotopic heart transplantation. Heart Lung 1996; 25:339-51. [PMID: 8886810 DOI: 10.1016/s0147-9563(96)80076-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVES The purpose of this study was to compare the effects of orthostatic stress on cardiovascular stability in heart transplant recipients early and late after transplantation and in healthy controls. BACKGROUND After transplantation, cardiac reinnervation is heterogeneous, with reports of sympathetic reinnervation after 5 months and parasympathetic reinnervation after 2 to 3 years. METHODS Sixteen heart transplant recipients early (less than 5 months) after transplantation, 17 recipients late (1 year or more) after transplantation, and 16 matched healthy controls were subjected to 45 minutes of passive upright tilt, with the following variables measured before, during, and after the procedure: cardiac output, heart rate, stroke volume, mean arterial pressure, systemic vascular resistance, and plasma norepinephrine. RESULTS At rest, heart rate (p < 0.0005) and mean arterial pressure (p = 0.003) were higher, and stroke volume was lower (p < 0.0005), in transplant recipients than they were in controls. With orthostasis, heart rate increased by 30% in controls and by 23% in the late posttransplantation group compared with 13% in the early posttransplantation group (p = 0.028); drop in stroke volume was three times more among controls than among those in either transplantation group (p < 0.001); late transplant recipients had higher norepinephrine increases than did the other two groups (p = 0.012). CONCLUSION With the exception of heart rate, patterns of hemodynamic response to orthostatic stress after transplantation remain consistent over time and differ from controls. Among transplant recipients, higher mean arterial pressure mitigates the force of gravity and prevents drops in stroke volume. Clinicians may anticipate that transplant recipients will tolerate postural maneuvers well. Later after transplantation, however, orthostatic tolerance is associated with increased norepinephrine release, consistent with enhanced sympathoactivation.
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Affiliation(s)
- L V Doering
- University of California, School of Nursing, Los Angeles 90095-6918, USA
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17
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Abstract
Neurocardiogenic syncope is a collective term used to describe the clinical syndromes of syncope that result from inappropriate, and often excessive, autonomic reflex activity, and manifest as abnormalities in the control of vascular tone and heart rate. These include carotid sinus syndrome, vasovagal syncope, and the syndromes of cough, deglutition, and micturition syncope. Orthostatic hypotension, which, in contrast, results from a failure of autonomic reflexes, is not considered part of this family of closely related syndromes. This review will focus on vasovagal and carotid sinus syndromes.
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Affiliation(s)
- R Sutton
- Royal Brompton Hospital, London, United Kingdom
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18
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Baily RG, Davis D, Clemson B, Zelis R. Normalization of the norepinephrine kinetic response to orthostatic stress after cardiac transplantation. Am J Cardiol 1994; 74:624-5. [PMID: 8074053 DOI: 10.1016/0002-9149(94)90759-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- R G Baily
- Department of Medicine, Milton S. Hershey Medical Center, Pennsylvania State University 17033
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Vezina WC, McAlister VC, Wall WJ, Engel CJ, Grant DR, Ghent CN, Hutton LC, King ME, Chey WY. Normal fasting volume and postprandial emptying of the denervated donor gallbladder in liver transplant recipients. Gastroenterology 1994; 107:847-53. [PMID: 8076771 DOI: 10.1016/0016-5085(94)90135-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND/AIMS Truncal vagotomy causes gallbladder dilatation and possibly cholelithiasis. During liver transplantation, when the gallbladder is transplanted with the donor liver, the gallbladder and liver are extrinsically denervated. The aim of this study was to determine whether extrinsic denervation affects gallbladder volume and postprandial emptying. METHODS To evaluate fasting gallbladder volume, 26 transplant recipients underwent ultrasonography. Twenty-eight normal volunteers were controls. To evaluate postprandial contractility, seven transplant recipients underwent radionuclide gallbladder-emptying studies. Gastric emptying and cholecystokinin release were simultaneously determined after a fatty meal to exclude a difference in gallbladder stimulus. Sixteen normal volunteers were controls. RESULTS There were no differences in fasting gallbladder volume or postprandial contractility, gastric emptying, and cholecystokinin release between transplant patients and controls. Median fasting and postprandial gallbladder volumes for the transplant recipients (95% confidence) were 16 mL (12-34 mL) and 3 mL (0-8 mL), respectively, and for controls were 18 mL (13-21 mL; P = 0.73) and 3 mL (1-6 mL; P = 0.97), respectively. CONCLUSIONS These data do not show gallbladder dilatation or impaired postprandial gallbladder contraction in the extrinsically denervated gallbladder. This finding suggests that gallbladder dilatation may be caused by the unopposed activity of the sympathetic system after truncal vagotomy.
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Affiliation(s)
- W C Vezina
- Department of Nuclear Medicine, University Hospital, London, Ontario, Canada
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Abstract
To determine the effect of tilt isoproterenol provocation on cerebral perfusion in a patient with denervated heart, transcranial Doppler sonography was used to assess changes in cerebral blood flow velocity during upright tilt test. A 51-year-old man with history of syncopal spells after heart transplantation was evaluated by using upright tilt test with and without isoproterenol for 30 minutes, respectively, at 80 degrees inclined. Mean cerebral blood flow was measured in the main stem of the right middle cerebral artery. Blood pressure and heart rate were noninvasively monitored. Tilt isoproterenol provocation but not tilt alone induced a significant reduction in cerebral blood flow velocity, without remarkable hypotension. There was no change in respiratory activity. This may indicate that vagal reflexes are not implicated in the mechanism of isoproterenol to induce cerebral hypoperfusion and hence neurally mediated syncope.
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Affiliation(s)
- P C Njemanze
- Noninvasive Flow Neurocybernetic Laboratory, Chidicon Medical Center, Owerri Imo State, Nigeria
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Madsen P, Iversen H, Secher NH. Central venous oxygen saturation during hypovolaemic shock in humans. Scand J Clin Lab Invest 1993; 53:67-72. [PMID: 8451602 DOI: 10.1080/00365519309092533] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We compared central venous oxygen saturation and central venous pressure (CVP) as indices of the effective blood volume during 50 degrees head-up tilt (anti-Trendelenburg's position) induced hypovolaemic shock in eight healthy subjects. Head-up tilt increased thoracic electrical impedance from 31 (28-36) (median and range) to 34 (30-40) Ohm, mean arterial pressure (MAP) from 79 (70-88) to 86 (80-99) mmHg, heart rate (HR) from 67 (56-71) to 99 (78-119) beats min-1 (p < 0.01) and total peripheral resistance (TPR) from 20 (16-32) to 36 (15-52) mmHg min l-1 (p < 0.03). Cardiac output decreased from 4.3 (3.0-4.8) to 2.7 (1.8-4.8) l min-1 (p < 0.03). After 29 (9-56) min presyncopal symptoms appeared, together with a decrease in MAP to 63 (43-79) mmHg, HR to 68 (30-112) beats min-1 and TPR to 22 (13-33) mmHg min l-1 (p < 0.02). During tilting CVP decreased from 3 (1-6) to 1 (-3-5) mmHg (p < 0.05) but thereafter remained stable. In contrast, central venous oxygen saturation showed a linear decrease with time from 0.75 (0.69-0.78) at rest to 0.60 (0.49-0.67) (p < 0.01) when presyncopal symptoms appeared. Central venous catheterization is a tool for measurement of central venous oxygen saturation in addition to recording of CVP. The results suggest that a reduced central blood volume is reflected more clearly in central venous oxygen saturation than in CVP.
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Affiliation(s)
- P Madsen
- Department of Anaesthesia, Rigshospitalet, Copenhagen, Denmark
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Thompson CJ, Leslie PJ, Lightman SL, Clarke BF, Ewing DJ. Regulation of ANP secretion in insulin-dependent diabetes mellitus and the influence of autonomic neuropathy. REGULATORY PEPTIDES 1991; 36:311-9. [PMID: 1839570 DOI: 10.1016/0167-0115(91)90065-o] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In order to determine the effect of diabetic autonomic neuropathy (DAN) on the atrial natriuretic peptide (ANP) response to dynamic stimuli, we studied the ANP response to 60 degrees head-up and 60 degrees leg-up tilt in diabetic subjects with (DAN + ve, n = 8) and without (DAN - ve, n = 8) evidence of autonomic neuropathy and seven matched non-diabetic controls. Mean baseline plasma ANP concentrations were similar in all three groups. Head-up tilt was associated with a fall in plasma ANP in all seven healthy controls (21.8 (16.8-30.7) to 16.8 (7.1-29.1), P = 0.06, mean (range)), seven of the eight DAN - ve (16.9 (6.5-33.7) to 8.5 (3.0-21.1), P = 0.015) and all eight DAN + ve subjects (27.3 (8.5-101.5) to 15.4 (1.0-67.6), P = 0.044). Leg-up tilt caused a rise in plasma ANP in six of the seven healthy controls (17.6 (7.5-27.9) to 22.4 (15.2-48.1), P = 0.041), six of the eight DAN - ve (12.5 (7.8-27.8) to 15.5 (7.3-31.3), P = 0.054) and seven of the eight DAN + ve subjects (18.2 (2.8-55.1) to 25.1 (4.5-92.8), P = 0.013). There was no significant difference in the fall in plasma ANP during head-up tilt or in the rise in plasma ANP during leg-up tilt between the three groups. We conclude that the regulation of ANP secretion is normal in diabetes mellitus, and is unaffected by the presence of autonomic neuropathy.
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Affiliation(s)
- C J Thompson
- Department of Medicine, Royal Infirmary, Edinburgh U.K
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