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 acute sympathetic nervous system activation on flow-mediated dilation of brachial artery

2006 ◽  
Vol 290 (4) ◽  
pp. H1446-H1453 ◽  
Author(s):  
Kenneth S. Dyson ◽  
J. Kevin Shoemaker ◽  
Richard L. Hughson
Keyword(s):  
Nervous System ◽  
Sympathetic Nervous System ◽  
Brachial Artery ◽  
Cold Pressor Test ◽  
Plasma Norepinephrine ◽  
Flow Mediated Dilation ◽  
Brachial Artery Diameter ◽  
Peak Shear Stress ◽  
Sympathetic Nervous ◽  
General Response

We tested the hypothesis that flow-mediated dilation (FMD) of the brachial artery would be impaired by acute increases in sympathetic nervous system activity (SNA) in models where similar peak shear stress stimulus was achieved by varying the duration of forearm muscle ischemia. Eleven healthy young men were studied under four different conditions, each with its own control: lower body suction (LBS), cold pressor test (CPT), mental arithmetic task (MAT), and activation of muscle chemoreflex (MCR). The duration of ischemia before observation of FMD by ultrasound imaging was 5 min each for control, LBS, and CPT; 3 min for MAT; and 2-min for MCR. Peak shear rate was not different between control and any of the SNA conditions, although total shear in the first minute was reduced in MAT. MCR was the only condition in which brachial artery vasoconstriction was observed before forearm occlusion [4.38 (SD 0.53) vs. control 4.60 (SD 0.53) mm, P < 0.05]; however, diameter increased to the same absolute value as that of the control, so the percent FMD was greater for MCR [9.85 (SD 2.33) vs. control 5.29 (SD 1.50)%]. Blunting of the FMD response occurred only in the CPT model [1.51 (SD 1.20)%]. During SNA, the increase in plasma cortisol from baseline was significant only for MCR; the increase in plasma norepinephrine was significant for MCR, LBS, and CPT; and the increase in epinephrine was significant only for MCR. These results showed that the four models employed to achieve increases in SNA had different effects on baseline brachial artery diameter and that blunted FMD is not a general response to increased SNA.

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.

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

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.

scholarly journals Detection of Changes in Renal Blood Flow Using Arterial Spin Labeling MRI

2021 ◽  
Vol 52 (1) ◽  
pp. 69-75
Author(s):  
Dennis Kannenkeril ◽  
Rolf Janka ◽  
Agnes Bosch ◽  
Susanne Jung ◽  
Julie Kolwelter ◽  
...  
Keyword(s):  
Blood Flow ◽  
Nervous System ◽  
Sympathetic Nervous System ◽  
Renal Blood Flow ◽  
Arterial Spin Labeling ◽  
Cold Pressor Test ◽  
Spin Labeling ◽  
Small Sample ◽  
Pharmacological Intervention ◽  
Sympathetic Nervous

Background: Alteration in kidney perfusion is an early marker of renal damage. The purpose of this study was to evaluate if changes in renal blood flow (RBF) could be detected using MRI with arterial spin labeling (ASL) technique. Methods: RBF as assessed by cortical (CRBF), medullary, and total renal blood flow (TRBF) were measured by MRI with arterial spin labeling (ASL-MRI) using flow-sensitive alternating inversion recovery true fast imaging with steady-state precession sequence. In 11 normotensive healthy individuals (NT) and 11 hypertensive patients (HT), RBF was measured at baseline and after both feet were covered with cold ice packs (cold pressor test) that activates the sympathetic nervous system. In another experiment, RBF was measured in 10 patients with CKD before and after a pharmacological intervention. We compared RBF measurements between the 3 study populations. Results: A significant reduction in CRBF (p = 0.042) and a trend in TRBF (p = 0.053) were observed in response to the activation of the sympathetic nervous system. A trend toward reduction of CRBF (p = 0.051) and TRBF (p = 0.059) has been detected after pharmacological intervention. TRBF was significantly lower in patients with HT and CKD patients compared to NT individuals (NT vs. HT, p = 0.014; NT vs. CKD, p = 0.004). TRBF was lower in patients with CKD compared to HT (p = 0.047). Conclusion: Our data indicate that both acute and short-term changes in RBF could be detected using ASL-MRI. We were able to detect differences in RBF between healthy and diseased individuals by needing only small sample size per group. Thus, ASL-MRI offers an advantage in conducting clinical trials compared to other technologies.

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