scholarly journals Neck movement but not neck position modulates skin sympathetic nerve activity supplying the lower limbs of humans

2018 ◽  
Vol 119 (4) ◽  
pp. 1283-1290
Author(s):  
Philip S. Bolton ◽  
Elie Hammam ◽  
Vaughan G. Macefield
Keyword(s):  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
The Body ◽  
Respiratory Frequency ◽  
Lower Limbs ◽  
Neck Movement ◽  
Nerve Activity ◽  
Skin Sympathetic Nerve Activity ◽  
Cross Correlation Analysis ◽  
Significant Difference

We previously showed that dynamic, but not static, neck displacement modulates muscle sympathetic nerve activity (MSNA) to lower limbs of humans. However, it is not known whether dynamic neck displacement modulates skin sympathetic nerve activity (SSNA). Tungsten microelectrodes inserted into the common peroneal nerve were used to record SSNA in 5 female and 4 male subjects lying supine on a table that fixed their head in space but allowed trapezoidal ramp (8.1 ± 1.2°/s) and hold (17.5° for 53 s) or sinusoidal (35° peak to peak at 0.33–0.46 Hz) horizontal displacement of the body about the head. SSNA recordings were made before, during, and after trapezoidal and sinusoidal displacements of the body. Spike frequency analysis of trapezoidal displacements and cross-correlation analysis during sinusoidal displacements revealed that SSNA was not changed by trapezoid body-only displacement but was cyclically modulated during sinusoidal angular displacements (median, 95% CI: 27.9%, 19.6–48.0%). The magnitude of this modulation was not statistically ( P > 0.05) different from that of cardiac and respiratory modulation at rest (47.1%, 18.7–56.3% and 48.6%, 28.4–59.3%, respectively) or during sinusoidal displacement (10.3%, 6.2–32.1% and 26.9%, 13.6–43.3%, respectively). Respiratory frequency was entrained above its resting rate (0.26 Hz, 0.2–0.29 Hz) during sinusoidal neck displacement; there was no significant difference ( P > 0.05) between respiratory frequency (0.38 Hz, 0.25–0.49 Hz) and sinusoidal displacement frequency (0.39 Hz, 0.35–0.42 Hz). This study provides evidence that SSNA is modulated during neck movement, raising the possibility that neck mechanoreceptors may contribute to the cutaneous vasoconstriction and sweat release associated with motion sickness. NEW & NOTEWORTHY This study demonstrates that dynamic, but not static, stretching of the neck modulates skin sympathetic nerve activity in the lower limbs.

scholarly journals Temporal Clustering of Skin Sympathetic Nerve Activity Bursts in Acute Myocardial Infarction Patients

2021 ◽  
Vol 15 ◽  
Author(s):  
Chun Liu ◽  
Chien-Hung Lee ◽  
Shien-Fong Lin ◽  
Wei-Chung Tsai
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
The Body ◽  
Nerve Activity ◽  
Skin Sympathetic Nerve Activity ◽  
Non Invasive ◽  
Temporal Clustering ◽  
Comparison Results

Backgrounds: Acute myocardial infarction (AMI) affects the autonomic nervous system (ANS) function. The aim of our study is to detect the particular patterns of ANS regulation in AMI. We hypothesize that altered ANS regulation in AMI patients causes synchronized neural discharge (clustering phenomenon) detected by non-invasive skin sympathetic nerve activity (SKNA).Methods: Forty subjects, including 20 AMI patients and 20 non-AMI controls, participated in the study. The wide-band bioelectrical signals (neuECG) were continuously recorded on the body surface for 5 min. SKNA was signal processed to depict the envelope of SKNA (eSKNA). By labeling the clusters, the AMI subjects were separated into non-AMI, non-cluster appearing (AMINCA), and cluster appearing (AMICA) groups.Results: The average eSKNA was significantly correlated with HRV low-frequency (LF) power (rho = −0.336) and high-frequency power (rho = −0.372). The cross-comparison results demonstrated that eSKNA is a valid surrogate marker to assess ANS in AMI patients. The frequency of cluster occurrence was 0.01–0.03 Hz and the amplitude was about 3 μV. The LF/HF ratio of AMICA (median: 1.877; Q1–Q3: 1.483–2.413) revealed significantly lower than AMINCA (median: 3.959; Q1–Q3: 1.840–6.562). The results suggest that the SKNA clustering is a unique temporal pattern of ANS synchronized discharge, which could indicate the lower sympathetic status (by HRV) in AMI patients.Conclusion: This is the first study to identify SKNA clustering phenomenon in AMI patients. Such a synchronized nerve discharge pattern could be detected with non-invasive SKNA signals. SKNA temporal clustering could be a novel biomarker to classify ANS regulation ability in AMI patients.Clinical and Translational Significance: SKNA is higher in AMI patients than in control and negatively correlates with parasympathetic parameters. SKNA clustering is associated with a lower LF/HF ratio that has been shown to correlate with sudden cardiac death in AMI. The lack of SKNA temporal clustering could indicate poor ANS regulation in AMI patients.

Abstract 529: Muscle Sympathetic Nerve Activity is Higher in Winter than Other Seasons

Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Jian Cui ◽  
Matthew D Muller ◽  
Allen R Kunselman ◽  
Cheryl Blaha ◽  
Lawrence I Sinoway
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Muscle Sympathetic Nerve Activity ◽  
Epidemiological Data ◽  
Repeated Measurements ◽  
Nerve Activity ◽  
Cardiovascular Morbidity And Mortality ◽  
Significant Difference

Epidemiological data suggest that blood pressure tends to be higher in winter and lower in summer, particularly in the elderly. Moreover, hospitalization and mortality rates due to cardiovascular disease have higher rates in winter than summer. Whether autonomic adjustment including muscle sympathetic nerve activity (MSNA) varies with season is unclear. To test the hypothesis that resting MSNA varies along the seasons, we retrospectively analyzed the supine baseline (6 min) MSNA and heart rate (from ECG) of 57 healthy subjects (33M, 24F, 29 ± 1 yrs, range 22-64 yrs) from studies in our laboratory (room temperature ~23 °C). Each of these subjects from central Pennsylvania was studied during 2 or more seasons (total 231 visits). A linear-mixed effects model, which is an extension of the analysis of variance model accounting for repeated measurements (i.e. season) per subject, was used to assess the association of season with the cardiovascular outcomes. The Tukey-Kramer procedure was used to account for multiple comparisons testing between the seasons. MSNA burst rate in winter (21.3 ± 1.0 burst/min) was significantly greater than in summer (13.7 ± 1.0 burst/min, P < 0.001), spring (17.5 ± 1.6 burst/min, P = 0.04) and fall (17.0 ± 1.2 burst/min, P < 0.002). There was no significant difference in MSNA in other comparisons (spring vs. summer, P = 0.12; spring vs. fall, P = 0.99; summer vs. fall, P = 0.054). Heart rate (63.6 ± 1.1 vs. 60.8 ± 1.2 beats/min, P = 0.048) was significantly greater in winter compared to summer. Blood pressure (automated sphygmomanometry of the brachial artery) was not significantly different between seasons. The results suggest that baseline sympathetic nerve activity varies along the seasons, with peak levels evident in winter. We speculate that the seasonal MSNA variation may contribute to seasonal variations in cardiovascular morbidity and mortality.

Pulse-synchronous sympathetic burst power as a new index of sympathoexcitation in patients with heart failure

2004 ◽  
Vol 287 (4) ◽  
pp. H1821-H1827 ◽  
Author(s):  
Yoshitaka Oda ◽  
Hidetsugu Asanoi ◽  
Hiroshi Ueno ◽  
Kunihiro Yamada ◽  
Shuji Joho ◽  
...  
Keyword(s):  
Heart Failure ◽  
Sympathetic Nerve ◽  
Sympathetic Activity ◽  
Sympathetic Nerve Activity ◽  
Class Ii ◽  
Plasma Norepinephrine ◽  
Class Iii ◽  
Nerve Activity ◽  
Significant Difference ◽  
Patients With Heart Failure

The upper limit of incidence of muscle sympathetic neural bursts can lead to underestimation of sympathetic activity in patients with severe heart failure. This study aimed to evaluate the pulse-synchronous burst power of muscle sympathetic nerve activity (MSNA) as a more specific indicator that could discriminate sympathetic activity in patients with heart failure. In 54 patients with heart failure, the pulse-synchronous burst power at the mean heart rate was quantified by spectral analysis of MSNA. Thirteen patients received a central sympatholytic agent (guanfacine) for 5 days to validate the feasibility of this new index. Both burst incidence and plasma norepinephrine level showed no significant difference between patients in New York Heart Association functional class III (94 ± 6 per 100 heartbeats and 477 ± 219 pg/ml, respectively) and class II (79 ± 14 per 100 heartbeats and 424 ± 268 pg/ml, respectively). In contrast, the burst power was useful for discriminating patients in class III from those in class II (61 ± 8% vs. 39 ± 10%; P < 0.05). Inhibition of sympathetic nerve activity by guanfacine was more sensitively reflected by the change of burst power (−36 ± 25%) than by that of burst incidence (−12 ± 14%; P < 0.001). The sympathetic burst power reflects both burst frequency and amplitude independently of the absolute values and provides a sensitive new index for interindividual comparisons of sympathetic activity in patients with heart failure.

Assessment of mechanical and thermal thresholds of human C nociceptors during increases in skin sympathetic nerve activity

2002 ◽  
Vol 113 (9) ◽  
pp. 1485-1490 ◽  
Author(s):  
Mitsuhiro Watanabe ◽  
Shinobu Toma ◽  
Masazumi Murakami ◽  
Ichiro Shimoyama ◽  
Yoshio Nakajima ◽  
...  
Keyword(s):  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Nerve Activity ◽  
Thermal Thresholds ◽  
Skin Sympathetic Nerve Activity
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