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Butler JM, Frampton CM, Moore G, Barclay ML, Jardine DL. Immediate effect of caffeine on sympathetic nerve activity: why coffee is safe? A single-centre crossover study. Clin Auton Res 2023; 33:623-633. [PMID: 37598402 PMCID: PMC10751260 DOI: 10.1007/s10286-023-00967-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 07/11/2023] [Indexed: 08/22/2023]
Abstract
PURPOSES Habitual coffee drinking is ubiquitous and generally considered to be safe despite its transient hypertensive effect. Our purpose was to determine the role of the sympathetic nervous system in the hypertensive response. METHODS In a single-centre crossover study, medical caregivers were studied after consumption of standard coffee (espresso), water and decaffeinated coffee (decaff) given in random order at least 1 month apart. Plasma caffeine levels, mean arterial pressure, heart rate, total peripheral resistance and muscle sympathetic activity were recorded. Baroreflex activity was assessed using burst incidence and RR interval changes to spontaneous blood pressure fluctuations. RESULTS A total of 16 subjects (mean [± standard error] age 34.4 ± 2 years; 44% female) were recruited to the study. Three agents were studied in ten subjects, and two agents were studied in six subjects. Over a 120-min period following the consumption of standard coffee, mean (± SE) plasma caffeine levels increased from 2.4 ± 0.8 to 21.0 ± 4 µmol/L and arterial pressure increased to 103 ± 1 mmHg compared to water (101 ± 1 mmHg; p = 0.066) and decaff (100 ± 1 mmHg; p = 0.016). Peripheral resistance in the same period following coffee increased to 120 ± 4% of the baseline level compared to water (107 ± 4; p = 0.01) and decaff (109 ± 4; p = 0.02). Heart rate was lower after both coffee and decaff consumption: 62 ± 1 bpm compared to water (64 bpm; p = 0.01 and p = 0.02, respectively). Cardio-vagal baroreflex activity remained stable after coffee, but sympathetic activity decreased, with burst frequency of 96 ± 3% versus water (106 ± 3%; p = 0.04) and decaff (112 ± 3%; p = 0.001) despite a fall in baroreflex activity from - 2.2 ± 0.1 to - 1.8 ± 0.1 bursts/100 beats/mmHg, compared to water (p = 0.009) and decaff (p = 0.004). CONCLUSION The hypertensive response to coffee is secondary to peripheral vasoconstriction but this is not mediated by increased sympathetic nerve activity. These results may explain why habitual coffee drinking is safe.
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Affiliation(s)
- Jennifer M Butler
- Department of General Medicine, Christchurch Hospital, 2 Riccarton Ave, Private Bag 4710, Christchurch, New Zealand
| | - Christopher M Frampton
- Department of Medicine, Christchurch School of Medicine, University of Otago, Dunedin, New Zealand
| | - Grant Moore
- Department of Toxicology, Christchurch Hospital, 2 Riccarton Ave, Christchurch, New Zealand
| | - Murray L Barclay
- Department of Medicine, Christchurch School of Medicine, University of Otago, Dunedin, New Zealand
- Department of Clinical Pharmacology, Christchurch Hospital, 2 Riccarton Ave, Christchurch, New Zealand
| | - David L Jardine
- Department of General Medicine, Christchurch Hospital, 2 Riccarton Ave, Private Bag 4710, Christchurch, New Zealand.
- Department of Medicine, Christchurch School of Medicine, University of Otago, Dunedin, New Zealand.
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Differential Effects of Angiotensin-II Compared to Phenylephrine on Arterial Stiffness and Hemodynamics: A Placebo-Controlled Study in Healthy Humans. Cells 2021; 10:cells10051108. [PMID: 34062957 PMCID: PMC8147945 DOI: 10.3390/cells10051108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 04/01/2021] [Accepted: 04/09/2021] [Indexed: 11/17/2022] Open
Abstract
The α1-adrenoceptor agonist phenylephrine (PE) and Angiotensin II (Ang II) are both potent vasoconstrictors at peripheral resistance arteries. PE has pure vasoconstrictive properties. Ang II, additionally, modulates central nervous blood pressure (BP) control via sympathetic baroreflex resetting. However, it is unknown whether Ang II vs. PE mediated vasoconstriction at equipressor dose uniformly or specifically modifies arterial stiffness. We conducted a three-arm randomized placebo-controlled cross-over trial in 30 healthy volunteers (15 female) investigating the effects of Ang II compared to PE at equal systolic pressor dose on pulse wave velocity (PWV), pulse wave reflection (augmentation index normalized to heart rate 75/min, AIx) and non-invasive hemodynamics by Mobil-O-Graph™ and circulating core markers of endothelial (dys-)function. PE but not Ang II-mediated hypertension induced a strong reflex-decrease in cardiac output. Increases in PWV, AIx, total peripheral resistance and pulse pressure, in contrast, were stronger during PE compared to Ang II at equal mean aortic BP. This was accompanied by minute changes in circulating markers of endothelial function. Moreover, we observed differential hemodynamic changes after stopping either vasoactive infusion. Ang II- and PE-mediated BP increase specifically modifies arterial stiffness and hemodynamics with aftereffects lasting beyond mere vasoconstriction. This appears attributable in part to different interactions with central nervous BP control including modified baroreflex function.
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Sayk F, Twesten C, Adametz I, Franzen K, Vonthein R, Dodt C, Meusel M. Angiotensin II-mediated nondipping during sleep in healthy humans: effects on baroreflex function at subsequent daytime. Am J Physiol Regul Integr Comp Physiol 2020; 318:R813-R821. [DOI: 10.1152/ajpregu.00355.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Blood pressure dipping at night is mediated by sleep-inherent, active downregulation of sympathetic vascular tone. Concomitantly, activity of the renin-angiotensin system is reduced, which might contribute to the beneficial effect of baroreflex downward resetting on daytime blood pressure homeostasis. To evaluate whether experimental nondipping mediated by angiotensin II during sleep would alter blood pressure and baroreflex function the next day in healthy humans, angiotensin-II or placebo (saline) was infused for a 7-h period at night, preventing blood pressure dipping in 11 sleeping normotensive individuals (5 males, balanced, crossover design). Baroreflex function was assessed about 1 h upon awakening and stop of infusion via microneurographic recordings of muscle sympathetic nerve activity (MSNA), showing that resting MSNA was significantly increased following angiotensin II nondipping compared with placebo ( P = 0.029), whereas blood pressure and heart rate remained unchanged. Baroreflex sensitivity in response to vasoactive drug challenge was preserved, and neuroendocrine markers of fluid balance and electrolytes did not differ between conditions. Ambulatory blood pressure during subsequent daytime was not altered. Data were compared with analog experiments previously performed within the same subjects during awake daytime (ANCOVA). We conclude that angiotensin-II mediated nocturnal nondipping did not induce blood pressure elevation at subsequent daytime in healthy humans but was linked to increased vasoconstrictive sympathetic activity. This is in contrast to a prolonged increase in blood pressure in corresponding daytime experiments of the same individuals. Evidently, sleep strongly preserves normotensive blood pressure homeostasis in healthy humans.
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Affiliation(s)
- Friedhelm Sayk
- Department of Internal Medicine, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Christoph Twesten
- Department of Internal Medicine, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Isabel Adametz
- Institute of Radiology, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Klaas Franzen
- Department of Internal Medicine, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Reinhard Vonthein
- Institute of Medical Biometry and Statistics, University of Lübeck, Lübeck, Germany
| | - Christoph Dodt
- Department of Emergency Medicine, München-Bogenhausen Hospital, München, Germany
| | - Moritz Meusel
- Department of Cardiology and Angiology, University Heart Center Lübeck, University Hospital of Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
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Guo Q, Feng X, Xue H, Jin S, Teng X, Duan X, Xiao L, Wu Y. Parental Renovascular Hypertension-Induced Autonomic Dysfunction in Male Offspring Is Improved by Prenatal or Postnatal Treatment With Hydrogen Sulfide. Front Physiol 2019; 10:1184. [PMID: 31607943 PMCID: PMC6761249 DOI: 10.3389/fphys.2019.01184] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 09/02/2019] [Indexed: 12/18/2022] Open
Abstract
Increasing evidence indicates there is a strong association between parental health during pregnancy and incidence of cardiovascular disease in adult offspring. Recently, hydrogen sulfide (H2S) has been demonstrated to be a powerful vasodilator of the placental vasculature, improving intrauterine growth restriction. In this study, we investigated whether parental hypertension induces autonomic dysfunction in male adult offspring, and the H2S mechanism underlying this autonomic dysfunction. 2-kidney-1-clip method was employed to induce parental hypertension during pregnancy and lactation in rats. Basal blood pressure (BP) and autonomic function of male offspring in adulthood was evaluated. Additionally, either maternal hypertensive dams or their male offspring after weaning were treated with H2S to determine improving effects of H2S on autonomic dysfunction. The BP was significantly increased in male offspring of renovascular hypertensive dams when compared to that in offspring of normotensive dams. The offspring of renovascular hypertensive dams also exhibited blunted baroreflex sensitivity, increased sympathetic effect and sympathetic tonus. Western blotting analysis revealed downregulation of endogenous H2S catalyzed enzyme and upregulation of angiotensin Ang II type 1 receptor (AT1R) pathway in the nucleus tractus solitarius and rostral ventrolateral medulla, two hindbrain nuclei involved in BP and autonomic regulation, in these offspring. Either prenatal or postnatal treatment with H2S improved the adverse effects. The results suggest that parental hypertension results in elevated BP and autonomic dysfunction in adult male offspring through activation of AT1R pathway and inhibition of endogenous H2S production in the brain.
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Affiliation(s)
- Qi Guo
- Department of Physiology, Hebei Medical University, Shijiazhuang, China
| | - Xiaohong Feng
- Department of Laboratory Diagnostics, Hebei Medical University, Shijiazhuang, China
| | - Hongmei Xue
- Department of Physiology, Hebei Medical University, Shijiazhuang, China.,Hebei Key Laboratory of Animal Science, Hebei Medical University, Shijiazhuang, China
| | - Sheng Jin
- Department of Physiology, Hebei Medical University, Shijiazhuang, China
| | - Xu Teng
- Department of Physiology, Hebei Medical University, Shijiazhuang, China.,Hebei Key Laboratory of Animal Science, Hebei Medical University, Shijiazhuang, China
| | - Xiaocui Duan
- Hebei Key Laboratory of Animal Science, Hebei Medical University, Shijiazhuang, China
| | - Lin Xiao
- Department of Physiology, Hebei Medical University, Shijiazhuang, China.,Hebei Key Laboratory of Animal Science, Hebei Medical University, Shijiazhuang, China
| | - Yuming Wu
- Department of Physiology, Hebei Medical University, Shijiazhuang, China.,Hebei Collaborative Innovation Center for Cardio-Cerebrovascular Disease, Shijiazhuang, China.,Key Laboratory of Vascular Medicine of Hebei Province, Shijiazhuang, China
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The renin-angiotensin system in cardiovascular autonomic control: recent developments and clinical implications. Clin Auton Res 2018; 29:231-243. [PMID: 30413906 DOI: 10.1007/s10286-018-0572-5] [Citation(s) in RCA: 144] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Accepted: 10/25/2018] [Indexed: 10/27/2022]
Abstract
Complex and bidirectional interactions between the renin-angiotensin system (RAS) and autonomic nervous system have been well established for cardiovascular regulation under both physiological and pathophysiological conditions. Most research to date has focused on deleterious effects of components of the vasoconstrictor arm of the RAS on cardiovascular autonomic control, such as renin, angiotensin II, and aldosterone. The recent discovery of prorenin and the prorenin receptor have further increased our understanding of RAS interactions in autonomic brain regions. Therapies targeting these RAS components, such as angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers, are commonly used for treatment of hypertension and cardiovascular diseases, with blood pressure-lowering effects attributed in part to sympathetic inhibition and parasympathetic facilitation. In addition, a vasodilatory arm of the RAS has emerged that includes angiotensin-(1-7), ACE2, and alamandine, and promotes beneficial effects on blood pressure in part by reducing sympathetic activity and improving arterial baroreceptor reflex function in animal models. The role of the vasodilatory arm of the RAS in cardiovascular autonomic regulation in clinical populations, however, has yet to be determined. This review will summarize recent developments in autonomic mechanisms involved in the effects of the RAS on cardiovascular regulation, with a focus on newly discovered pathways and therapeutic targets for this hormone system.
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