Reflex activation of sympathetic nervous system by ANF in humans

1988 ◽  
Vol 255 (3) ◽  
pp. H685-H689
Author(s):  
T. J. Ebert
Keyword(s):  
Nervous System ◽  
Sympathetic Nervous System ◽  
Sympathetic Activity ◽  
Muscle Sympathetic Nerve Activity ◽  
Venous Pressure ◽  
Isotonic Saline ◽  
Positive Pressure ◽  
Base Line ◽  
Lower Body Positive Pressure ◽  
Sympathetic Nervous

Recent studies in experimental animal preparations suggest that ANF might alter sympathetic nervous system function. In the present investigation, direct recordings of postganglionic muscle sympathetic nerve activity were obtained from the peroneal nerve of conscious human volunteers. These data and hemodynamic parameters were recorded before and during infusions of atrial natriuretic factor (ANF, 99–126) or placebo (isotonic saline) in 10 subjects. Base-line ANF (36.5 +/- 3.8) increased to 329 +/- 22 pg/ml during 20-min infusions of ANF (15 ng.kg-1.min-1). This did not alter heart rate or blood pressure but reduced central venous pressure (CVP) by 47 +/- 10% (P less than 0.01). Base-line-integrated sympathetic activity (14.4 +/- 2.4 bursts/min) increased 30 +/- 12% during ANF infusion (P less than 0.05). However, when CVP was fixed at control levels with head-down tilt or lower body positive pressure, sympathetic activity was unchanged from pre-ANF base-line levels. These data indicate that exogenous infusions of ANF reduced CVP and unloaded cardiopulmonary baroreceptors. This elicits reflex increases of muscle sympathetic efferent activity. When CVP is maintained at control levels, ANF does not alter sympathetic neural outflow to muscles.

Sympathetic nervous system contributes to the age-related impairment of flow-mediated dilation of the superficial femoral artery

2006 ◽  
Vol 291 (6) ◽  
pp. H3122-H3129 ◽  
Author(s):  
Dick H. J. Thijssen ◽  
Patricia de Groot ◽  
Miriam Kooijman ◽  
Paul Smits ◽  
Maria T. E. Hopman
Keyword(s):  
Nervous System ◽  
Sympathetic Nervous System ◽  
Femoral Artery ◽  
Superficial Femoral Artery ◽  
Sympathetic Activity ◽  
Cold Pressor Test ◽  
Young Men ◽  
Older Men ◽  
Flow Mediated Dilation ◽  
Sympathetic Nervous

The physiological aging process is associated with endothelial dysfunction, as assessed by flow-mediated dilation (FMD). Aging is also characterized by increased sympathetic tone. Therefore, the aim of the present study is to assess whether acute changes in sympathetic activity alter FMD in the leg. For this purpose, the FMD of the superficial femoral artery was determined in 10 healthy young (22 ± 1 yr) and 8 healthy older (69 ± 1 yr) men in three different conditions: 1) at baseline, 2) during reduction of sympathetic activity, and 3) during sympathetic stimulation. Reduction of sympathetic activity was achieved by performing a maximal cycling exercise, leading to postexercise attenuation of the sympathetic responsiveness in the exercised limb. A cold pressor test was used to increase sympathetic activity. Nitroglycerin (NTG) was used to assess endothelium-independent vasodilation in all three conditions. Our results showed that, in older men, the FMD and NTG responses were significantly lower compared with young men ( P = 0.001 and P = 0.02, respectively). In older men, sympathetic activity significantly affected the FMD response [repeated-measures (RM) ANOVA: P = 0.01], with a negative correlation between the level of sympathetic activity and FMD ( R = −0.41, P = 0.049). This was not the case for NTG responses (ANOVA; P = 0.48). FMD and NTG responses in young men did not differ among the three conditions (RM-ANOVA: P = 0.32 and P = 0.31, respectively). In conclusion, in older men, FMD of the femoral artery is impaired. Local attenuation of the sympathetic responsiveness partly restores the FMD in these subjects. In contrast, in young subjects, acute modulation of the sympathetic nervous system activity does not alter flow-mediated vasodilation in the leg.

Effect of lymphatic outflow pressure on lymphatic albumin transport in humans

2001 ◽  
Vol 91 (3) ◽  
pp. 1223-1228 ◽  
Author(s):  
Jauchia Wu ◽  
Gary W. Mack
Keyword(s):  
Protein Transport ◽  
Lower Body Negative Pressure ◽  
Venous Pressure ◽  
Isotonic Saline ◽  
Saline Infusion ◽  
Positive Pressure ◽  
Lower Body ◽  
Lower Body Positive Pressure ◽  
The Difference ◽  
The Impact

The effects of posture on the lymphatic outflow pressure and lymphatic return of albumin were examined in 10 volunteers. Lymph flow was stimulated with a bolus infusion of isotonic saline (0.9%, 12.6 ml/kg body wt) under four separate conditions: upright rest (Up), upright rest with lower body positive pressure (LBPP), supine rest (Sup), and supine rest with lower body negative pressure (LBNP). The increase in plasma albumin content (ΔAlb) during the 2 h after bolus saline infusion was greater in Up than in LBPP: 82.9 ± 18.5 vs. −28.4 mg/kg body wt. ΔAlb was greater in LBNP than in Sup: 92.6 vs. −22.5 ± 18.9 mg/kg body wt ( P < 0.05). The greater ΔAlb in Up and Sup with LBNP were associated with a lower estimated lymphatic outflow pressure on the basis of the difference in central venous pressure (ΔCVP). During LBPP, CVP was increased compared with Up: 3.8 ± 1.4 vs. −1.2 ± 1.2 mmHg. During LBNP, CVP was reduced compared with Sup: −3.0 ± 2.2 vs. 1.7 ± 1.0 mmHg. The translocation of protein into the vascular space after bolus saline infusion reflects lymph return of protein and is higher in Up than in Sup. Modulation of CVP with LBPP or LBNP in Up and Sup, respectively, reversed the impact of posture on lymphatic outflow pressure. Thus posture-dependent changes in lymphatic protein transport are modulated by changes in CVP through its mechanical impact on lymphatic outflow pressure.

Forearm training attenuates sympathetic responses to prolonged rhythmic forearm exercise

1996 ◽  
Vol 81 (4) ◽  
pp. 1778-1784 ◽  
Author(s):  
Lawrence Sinoway ◽  
Jeffrey Shenberger ◽  
Gretchen Leaman ◽  
Robert Zelis ◽  
Kristen Gray ◽  
...  
Keyword(s):  
Heart Rate ◽  
Nervous System ◽  
Sympathetic Nervous System ◽  
Sympathetic Nerve Activity ◽  
Muscle Sympathetic Nerve Activity ◽  
Voluntary Contraction ◽  
Nerve Activity ◽  
Sympathetic Nervous ◽  
Sympathetic Responses ◽  
Forearm Exercise

Sinoway, Lawrence, Jeffrey Shenberger, Gretchen Leaman, Robert Zelis, Kristen Gray, Robert Baily, and Urs Leuenberger.Forearm training attenuates sympathetic responses to prolonged rhythmic forearm exercise. J. Appl. Physiol. 81(4): 1778–1784, 1996.—We previously demonstrated that nonfatiguing rhythmic forearm exercise at 25% maximal voluntary contraction (12 2-s contractions/min) evokes sympathoexcitation without significant engagement of metabolite-sensitive muscle afferents (B. A. Batman, J. C. Hardy, U. A. Leuenberger, M. B. Smith, Q. X. Yang, and L. I. Sinoway. J. Appl. Physiol. 76: 1077–1081, 1994). This is in contrast to the sympathetic nervous system responses observed during fatiguing static forearm exercise where metabolite-sensitive afferents are the key determinants of sympathetic activation. In this report we examined whether forearm exercise training would attenuate sympathetic nervous system responses to rhythmic forearm exercise. We measured heart rate, mean arterial blood pressure (MAP), muscle sympathetic nerve activity (microneurography), plasma norepinephrine (NE), and NE spillover and clearance (tritiated NE kinetics) during nonfatiguing rhythmic forearm exercise before and after a 4-wk unilateral forearm training paradigm. Training had no effect on forearm mass, maximal voluntary contraction, or heart rate but did attenuate the increase in MAP (increase in MAP: from 15.2 ± 1.8 before training to 11.4 ± 1.4 mmHg after training; P < 0.017), muscle sympathetic nerve activity (increase in bursts: from 10.8 ± 1.4 before training to 6.2 ± 1.1 bursts/min after training; P < 0.030), and the NE spillover (increase in arterial spillover: from 1.3 ± 0.2 before training to 0.6 ± 0.2 nmol ⋅ min−1 ⋅ m−2after training, P < 0.014; increase in venous spillover: from 2.0 ± 0.6 before training to 1.0 ± 0.5 nmol ⋅ min−1 ⋅ m−2after training, P < 0.037) seen in response to exercise performed by the trained forearm. Thus forearm training reduces sympathetic responses during a nonfatiguing rhythmic handgrip paradigm that does not engage muscle metaboreceptors. We speculate that this effect is due to a conditioning-induced reduction in mechanically sensitive muscle afferent discharge.

Suppression of sympathetic nervous system is involved in hypotension and bradycardia during hemofiltration in anesthetized dogs

1995 ◽  
Vol 73 (10) ◽  
pp. 1495-1501 ◽  
Author(s):  
Tetsuya Hayashi ◽  
Toshishige Shibamoto ◽  
Yoshihiro Yamaguchi ◽  
Hong-Gang Wang ◽  
Satoshi Tanaka
Keyword(s):  
Nervous System ◽  
Sympathetic Nervous System ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Venous Pressure ◽  
Central Venous ◽  
Induced Hypotension ◽  
Anesthetized Dogs ◽  
Sympathetic Nervous

Hypotension occurring during hemodialysis is often accompanied by paradoxical bradycardia. However, the mechanism is poorly understood. This study was designed to determine the role of the sympathetic nervous system in hemodialysis-induced hypotension and bradycardia. We measured efferent sympathetic nerve activities to the heart (CNA), kidney (RNA), liver (HNA), spleen (SpNA), and adrenal gland (AdNA), along with heart rate (HR), blood pressure (BP), central venous pressure (CVP), and left atrial pressure (LAP) during hemofiltration performed at a rate of 0.3 mL∙kg−1∙min−1 for 30 min in anesthetized dogs. The response to hemorrhage was also studied at the same bleeding speed. Hemorrhage caused a decrease in BP (−18 ± 1 mmHg; 1 mmHg = 133.3 Pa) with reflex increases in HR (7 ± 2 beats/min) and sympathetic nerve activities. In contrast, hemofiltration caused a decrease in CNA (85 ± 18%), HNA (86 ± 11%), and SpNA (88 ± 11%) with greater decreases in BP (−43 ± 10 mmHg) and HR (−27 ± 14 beats/min) than hemorrhage. During hemofiltration, the decreases in BP, HR, CNA, HNA, and SpNA were attenuated after vagotomy. Hematocrit increased by 6.5% at 30 min after hemofiltration, whereas it decreased by 4.3% after hemorrhage. These results suggest that hemofiltration suppresses the sympathetic nervous system, resulting in decreases in HR and BP. Furthermore, this sympathetic suppression during hemofiltration is mediated by vagal afferents.Key words: hemodialysis, baroreceptor reflex, sympathetic nerve activity, hemorrhage, vagus nerve.

scholarly journals Elevated Activity of the Sympathetic Nervous System Is Related to Diminished Practice Effects in Memory: A Pilot Study

2021 ◽  
Vol 80 (4) ◽  
pp. 1675-1685
Author(s):  
Linda H.G. Pagen ◽  
Tom Smeets ◽  
Lisa Schmiedek ◽  
Michael A. Yassa ◽  
Frans R.J. Verhey ◽  
...  
Keyword(s):  
Nervous System ◽  
Pilot Study ◽  
Sympathetic Nervous System ◽  
Cognitive Decline ◽  
Sympathetic Activity ◽  
Practice Effects ◽  
Time Points ◽  
System Activation ◽  
Sympathetic Nervous ◽  
Sympathetic Nervous System Activation

Background: Reductions in memory practice effects have gained interest as risk factor for future cognitive decline. Practice effects vary with age and can be moderated by factors such as individual variability in arousal or stress experience acting as an additional cognitive load. Objective: In the current pilot study, we examined whether sympathetic nervous system activation moderates the relationship between age and practice effects. Methods: Thirty cognitively healthy individuals aged 40–70 years performed a mnemonic discrimination task twice. Salivary alpha amylase (sAA) samples were obtained at different time points as a proxy of sympathetic activity. Spearman correlations examined the relation between practice effects and sAA. Subsequently, age by sAA interactions on practice scores were explored with bootstrapped linear regression models. Additionally, participants were divided in learners (exhibiting practice effects) and non-learners based on the difference in mnemonic discrimination performance. Results: Higher age and baseline SNS activity were independently related to lower practice effects. The non-learners showed significantly higher sAA scores at all time points compared to learners. Among the learners, baseline-adjusted lower levels of sAA after encoding were associated with greater practice effects, particularly in middle-aged individuals. No such interaction was observed for non-learners. Conclusion: These results show that higher baseline sympathetic activation is associated with worse practice effects independently of age. Additionally, in a subgroup of middle-aged learners practice effects were observed when sympathetic activity remained low during learning. These findings suggest that elevated sympathetic nervous system activation may be a promising indicator of imminent cognitive decline.

Abstract 114: Renal Denervation Reduces Monocyte Activation: An Anti-inflammatory Effect Relevant for Cardiovascular Risk

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Maria Teresa Kristina Zaldivia ◽  
Jennifer Rivera ◽  
Dagmara Hering ◽  
Petra Marusic ◽  
Petra Marusic ◽  
...  
Keyword(s):  
Nervous System ◽  
Sympathetic Nervous System ◽  
Systemic Inflammation ◽  
Sympathetic Activity ◽  
Inflammatory Markers ◽  
Renal Denervation ◽  
Monocyte Activation ◽  
Hypertensive Patients ◽  
Post Procedure ◽  
Sympathetic Nervous

Background: Over-activation of renal sympathetic nervous system and low-grade systemic inflammation are thought to be common features of hypertension. Renal Denervation (RDN) reduces sympathetic activity in patients with resistant hypertension. However, its effect on systemic inflammation has not been investigated. Aim: To determine the effect of RDN-induced sympathetic inhibition on monocyte activation and systemic inflammation in hypertensive patients. Methods: Peripheral blood was obtained from 42 patients who underwent RDN for uncontrolled blood pressure (BP) at baseline, at 3 months and 6 months post-procedure. Ambulatory BP, overall activation status of monocyte as well as monocyte subsets and inflammatory markers were assessed at each time point. Results: RDN significantly lowered 24-hour ambulatory BP at 3 months (150.5/81.0 mmHg to 144.7/77.9 mmHg), which was sustained at 6 months (144.7/78.6 mmHg). The overall monocyte activation was significantly decreased (3 months, 4079.4 MFI to 3182.0 MFI; 6 months, 3457.62 MFI) post-RDN, specifically in the subset of classical monocytes (6 months, 4696.8 MFI to 3958.8 MFI). In line with this, reduction of several inflammatory markers were observed, including monocyte-platelet aggregates at 3 months (34% [680 of 2000 monocyte events] to 11.85% [237 of 2000 monocyte events]) and plasma levels of MCP-1 (3 months, 144.9 pg/ml to 100.1 pg/ml; 6 months, 122.2 pg/ml), IL-1β (3 months, 18.3 pg/ml to 10.8 pg/ml; 6 months, 12.2 pg/ml), TNF-α (3 months, 167.5 pg/ml to 78.4 pg/ml; 6 months, 111.1 pg/ml), IL-12 (3 months, 59.8 pg/ml to 9.9 pg/ml; 6 months, 21.4 pg/ml) and IL-6 (3 months, 2.4 pg/ml to 1.5pg/ml; 6 months, 1.9 pg/ml). A positive correlation was observed between baseline muscle sympathetic nerve activity and monocyte activation (R=0.62) and changes observed at both time points (3 months, R=0.63; 6 months, R=0.88) post-procedure. Conclusions: Inhibition of sympathetic activity via RDN is associated with a reduction of monocyte activation and other circulating inflammatory markers in hypertensive patients. These findings point to a direct interaction between the inflammatory and sympathetic nervous system, which is of central relevance for the understanding of beneficial cardiovascular effects of RDN.

Correlations of attended and unattended blood pressure with sympathetic nervous system activity in essential hypertension

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
E Manta ◽  
M Kouremeti ◽  
N Kakouri ◽  
A Kasiakogias ◽  
D Konstantinidis ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Nervous System ◽  
Essential Hypertension ◽  
Sympathetic Nervous System ◽  
Sympathetic Nerve ◽  
Muscle Sympathetic Nerve Activity ◽  
Left Ventricular ◽  
Hypertensive Group ◽  
Oscillometric Device ◽  
Sympathetic Nervous

Abstract Background/Introduction Measurement of unattended blood pressure (BP) may provide additional information over conventionally attended BP. Moreover, hypertension is related to sympathetic drive while there are scarce data on the diverse links of attended and unattended BP with muscle sympathetic nerve activity (MSNA) in hypertensive patients. Purpose The aim of this study was to appraise the relation of BP levels in the attended and unattended setting with MSNA in patients with essential hypertension. Methods We studied 117 patients with essential hypertension (age: 58±11 years, 60 males, office BP: 142/85±17/10 mmHg, 24-hour BP: 133/80±11/9 mmHg). In all participants sympathetic drive was assessed by MSNA estimations based on established methodology (microneurography). Both unattended BP (patient alone in the room, an oscillometric device programmed to perform 3 BP measurements, at 1-minute intervals, after 5 minutes) and attended BP were measured with the same device, on the same day of MSNA recording, in random order. Patients were divided into the combined attended and unattended hypertensive group when BP≥140/90 mmHg in both attended and unattended BP estimations and to the attended hypertensive group when only attended BP≥140/90 mmHg. Results Patients with combined attended and unattended hypertension (n=70) compared to those with attended hypertension (n=47) did not differ regarding 24-h ambulatory BP levels, glucose levels, renal function and left ventricular mass index (p=NS for all). Moreover, patients with combined attended and unattended hypertension compared to those with attended hypertension were characterized by greater levels of MSNA (43.7±9.9 vs 37.7±9.7 bursts per minute, p=0.032). In all participants, sympathetic nerve traffic as assessed by resting MSNA was related to attended systolic BP (r=0.270, p=0.003), attended diastolic BP (r=0.344, p=0.001), unattended systolic BP (r=0.263, p=0.004) and unattended diastolic BP (r=0.274, p=0.003). Conclusions The phenotype of combined attended and unattended hypertension compared to attended hypertension is accompanied by higher sympathetic nervous system activation. Moreover, the close association of MSNA with attended and unattended BP levels in essential hypertension, further supports the key role of sympathetic drive in modulating BP. Funding Acknowledgement Type of funding source: None

scholarly journals Sympathetic nervous system activity in rat thyroid: potential role in goitrogenesis

2005 ◽  
Vol 288 (5) ◽  
pp. E861-E867 ◽  
Author(s):  
James B. Young ◽  
M. Elizabeth Bürgi-Saville ◽  
Ulrich Bürgi ◽  
Lewis Landsberg
Keyword(s):  
Nervous System ◽  
Sympathetic Nervous System ◽  
Superior Cervical Ganglion ◽  
Sympathetic Activity ◽  
Sympathetic Nervous System Activity ◽  
System Activity ◽  
Nervous System Activity ◽  
Cervical Ganglion ◽  
Sympathetic Nervous ◽  
Rat Thyroid

The role of sympathetic innervation in regulation of thyroid function is incompletely understood. We, therefore, carried out studies in rats utilizing techniques of norepinephrine turnover to assess thyroid sympathetic activity in vivo. Thyroidal sympathetic activity was increased 95% by exposure to cold (4°C), 42% by chronic ingestion of an iodine-deficient diet, and 32% in rats fed a goitrogenic diet (low-iodine diet supplemented with propylthiouracil). In addition, fasting for 2 days reduced sympathetic nervous system activity in thyroid by 38%. Thyroid growth and 125I uptake were also compared in intact and decentralized hemithyroids obtained from animals subjected to unilateral superior cervical ganglion decentralization. Unilateral superior cervical ganglion decentralization led to a reduction in thyroid weight, in 125I uptake by thyroid tissue, and in TSH-induced stimulation of 125I uptake in decentralized hemithyroids. These results suggest that sympathetic activity in thyroid contributes to gland enlargement and may modulate tissue responsiveness to TSH.

Progesterone does not alter sympathetic activity in tissues involved in energy balance

1996 ◽  
Vol 134 (4) ◽  
pp. 508-512
Author(s):  
Marisa Puerta ◽  
César Venero ◽  
Carmen Castro ◽  
María Abelenda
Keyword(s):  
Nervous System ◽  
Energy Balance ◽  
Food Intake ◽  
Sympathetic Nervous System ◽  
Sympathetic Activity ◽  
Female Rats ◽  
Noradrenaline Content ◽  
Brown Adipose ◽  
Energy Stores ◽  
Sympathetic Nervous

Puerta M, Venero C, Castro C, Abelenda M. Progesterone does not alter sympathetic activity in tissues involved in energy balance. Eur J Endocrinol 1996;134:508–12. ISSN 0804–4643 Female rats acclimated to thermoneutrality to avoid cold influences received progesterone by means of subcutaneous implants. They increased their food intake and body weight above the values recorded in control animals. None the less, despite the enhanced food intake, no sign of activation of the sympathetic nervous system was observed, as judged by the unaltered noradrenaline content, half-life and turnover rate in brown adipose tissue, pancreas and heart. This indicates that progesterone increases food intake but prevents non-energy-conservation processes regulated by the sympathetic nervous system from taking place. Thus, it facilitates in two different ways the building up of energy stores. Because overfeeding induced by palatable diets increases the sympathetic tone to the organs studied, it is suggested that the central mechanisms regulating energy balance are probably influenced in a different manner by progesterone than by the sensory properties of palatable diets. M Puerta, Departamento de Biología Animal II (Fisiología Animal), Facultad de Ciencias Biológicas, Universidad Complutense de Madrid, E-28040 Madrid, Spain

scholarly journals Sympathetic nervous system and serum leptin level in obese patients with and without obstructive sleep apnea

2006 ◽  
Vol 12 (3) ◽  
pp. 256-261
Author(s):  
N. E. Zvartau ◽  
Yu. V. Sviryaev ◽  
O. P. Rotari ◽  
I. V. Emelyanov ◽  
N. K. Merculova ◽  
...  
Keyword(s):  
Obstructive Sleep Apnea ◽  
Nervous System ◽  
Sleep Apnea ◽  
Sympathetic Nervous System ◽  
Sympathetic Activity ◽  
Obese Patients ◽  
Serum Leptin ◽  
Nervous System Activity ◽  
Obstructive Sleep ◽  
Sympathetic Nervous

The aim of the present study was to investigate sympathetic nervous system activity and serum leptin level in obese patients with and without obstructive sleep apnea (OSA). We examined 75 OSA patients and 40 age, weight, BMI and blood pressure levels matched obese patients without OSA. As a result, patients with OSA had higher sympathetic activity associated not only with repetitive episodes of hypoxia/hypercapnia during sleep, but also with more marked central obesity and higher serum leptin level.

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