Relationships between activity of sympathetic nerve pairs: phase and coherence

Kocsis, Bernát; Gebber, Gerard L.; Barman, Susan M.; Kenney, Michael J.

doi:10.1152/ajpregu.1990.259.3.r549

Cited by 57 publications

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“…The coherence function (normalized cross-spectrum) provided a measure of the strength of linear correlation of rVLM neuronal activity and blood pressure at each frequency. Coherence values of Ն0.5 were chosen to reflect a statistically significant relationship between rVLM spikes and arterial blood pressure (5,30,53,57).…”

Section: Discussionmentioning

confidence: 99%

Medullary substrate and differential cardiovascular responses during stimulation of specific acupoints

Tjen‐A‐Looi

Longhurst

2004

American Journal of Physiology-Regulatory, Integrative and Comp

109

173

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Electroacupuncture (EA) at P5-P6 acupoints overlying the median nerve reduces premotor sympathetic cardiovascular neuronal activity in the rostral ventral lateral medulla (rVLM) and visceral reflex pressor responses. In previous studies, we have noted different durations of influence of EA comparing P5-P6 and S36 -S37 acupoints, suggesting that point specificity may exist. The purpose of this study was to evaluate the influence of stimulating P5-P6 (overlying the median nerve), LI4 -L7 (overlying branches of the median nerve and the superficial radial nerve), LI6 -LI7 (overlying the superficial radial nerve), LI10 -LI11 (overlying the deep radial nerves), S36 -S37 (overlying the deep peroneal nerves), or K1-B67 (overlying terminal branches of the tibial nerves) specific acupoints, overlying deep and superficial somatic nerves, on the excitatory cardiovascular reflex and rVLM responses evoked by stimulation of chemosensitive receptors in the cat's gallbladder with bradykinin (BK) or direct splanchnic nerve (SN) stimulation. We observed point-specific differences in magnitude and duration of EA inhibition between P5-P6 or LI10 -LI11 and LI4 -L7 or S36 -S37 in responses to 30-min stimulation with low-frequency, low-current EA. EA at LI6 -LI7 and K1-B67 acupoints as well as direct stimulation of the superficial radial nerve did not cause any cardiovascular or rVLM neuronal effects. Cardiovascular neurons in the rVLM, a subset of which were classified as premotor sympathetic cells, responded to brief (30 s) stimulation of the SN as well as acupoints P5-P6, LI10 -LI11, LI4 -L7, S36 -S37, LI6 -LI7, or K1-B67, or underlying somatic pathways in a fashion similar to the reflex responses. In fact, we observed a significant linear relationship (r 2 ϭ 0.71) between the evoked rVLM response and reflex change in mean arterial blood pressure. In addition, EA stimulation at P5-P6 and LI4 -L7 decreased rVLM neuronal activity by 41 and 12%, respectively, for Ͼ1 h, demonstrating that prolonged input into the medulla during stimulation of somatic nerves, depending on the degree of convergence, leads to more or less inhibition of activity of these cardiovascular neurons. Thus EA at acupoints overlying deep and superficial somatic nerves leads to point-specific effects on cardiovascular reflex responses. In a similar manner, sympathetic cardiovascular rVLM neurons that respond to both visceral (reflex) and somatic (EA) nerve stimulation manifest graded responses during stimulation of specific acupoints, suggesting that this medullary region plays a role in site-specific inhibition of cardiovascular reflex responses by acupuncture. somatic afferents; electroacupuncture; visceral afferents; rostral ventral lateral medulla; prolonged neuronal inhibition ALTERNATIVE MEDICINE is used with increasing frequency in the United States and most other countries. In particular, manual acupuncture and the potent alternative, electroacupuncture (EA), are used primarily for treatment of chronic ailments, including cardiovascular disease. Chinese and ...

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Section: Discussionmentioning

confidence: 99%

Medullary substrate and differential cardiovascular responses during stimulation of specific acupoints

Tjen‐A‐Looi

Longhurst

2004

American Journal of Physiology-Regulatory, Integrative and Comp

109

173

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“…Bilateral carotid sinus denervation was completed by removing the adventitia from the area of the carotid sinus bifurcation (22). Denervation was considered complete by the loss of coherence between the arterial pulse and SND (17) and/or the absence of a reflex change in SND from control levels during increases in arterial pressure produced by the administration of phenylephrine hydrochloride (3-5 g/kg iv) and during decreases in arterial pressure produced by the administration of sodium nitroprusside (3-5 g/kg iv).…”

Section: Methodsmentioning

confidence: 99%

“…Autospectral analysis of SND bursts was completed as previously described (17). Fast Fourier transform was performed on 12 contiguous windows of data that were 5 s in duration.…”

Section: Methodsmentioning

confidence: 99%

Sympathetic nerve regulation to heating is altered in senescent rats

Kenney

Fels

2002

American Journal of Physiology-Regulatory, Integrative and Comp

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Kenney, Michael J., and Richard J. Fels. Sympathetic nerve regulation to heating is altered in senescent rats. Am J Physiol Regulatory Integrative Comp Physiol 283: R513-R520, 2002. First published May 6, 2002 10.1152/ ajpregu.00683.2001.-Renal and splanchnic sympathetic nerve discharge (SND) responses to increased (38-41°C) internal temperature were determined in anesthetized young (3-6 mo old), mature (12 mo old), and senescent (24 mo old) Fischer 344 (F344) rats. We hypothesized that SND responses would be altered in senescent and mature rats as demonstrated by attenuated sympathoexcitatory responses to heating and by the absence of hyperthermia-induced SND pattern changes. The following observations were made. 1) Renal and splanchnic SND responses were significantly increased during heating in young and mature but not in senescent rats. 2) At 41°C, renal and splanchnic SND responses were higher in young compared with senescent rats, and renal SND was higher in mature than in senescent rats.3) Heating changed the SND bursting pattern in young, but not in mature or senescent, rats. 4) SND responses to heating did not differ between baroreceptor-innervated (BRI) and sinoaortic-denervated (SAD) senescent rats but were higher in SAD compared with BRI young rats. These results demonstrate an attenuated responsiveness of sympathetic neural circuits to heating in senescent F344 rats.Fischer 344 rats; sympathetic nerve discharge CHANGING THE LEVEL OF ACTIVITY in sympathetic nerves in response to acute environmental stress is a primary means by which mammals maintain physiological homeostasis. In young Sprague-Dawley rats, elevated internal body temperature (Tc) produced by acute heat stress increases efferent sympathetic nerve activity (9,12,13,15) and alters the pattern of sympathetic nerve discharge (SND) bursts (12,13,15). With respect to the SND bursting pattern, increased Tc transforms cardiac-related SND bursts to low-frequency bursts that contain more power than cardiac-related bursts, demonstrating an important role for pattern transformation in mediating heating-induced sympathoexcitatory responses (13).Aging is known to alter sympathetic nerve responses to various acute stressors, including hypoxia (30, 31), footshock (23), and 2-deoxy-D-glucose administration (23). In addition, senescent rats demonstrate altered norepinephrine turnover rates in selected organs during heating (18), suggesting age-related changes in sympathetic nerve responses to heating. However, our understanding of the effect of age on directly recorded SND responses to heating is limited in at least three ways. First, the effect of age on renal sympathetic nerve responses to increased Tc is not well established. Stauss et al. (32) reported that the level of renal SND remained unchanged in response to hyperthermia in 12-mo-old (mature) and 24-mo-old (senescent) Fischer 344 (F344) rats. However, renal SND responses to heating in young F344 rats were not reported. Therefore, it is not clear whether the lack of renal sympathoexcitation to...

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“…Koesis. Gebber, Barman & Kenney (1990) determined the coherence between different sympathetic nerve pairs using a similar analysis to that used here. There was correlated activity in the 2-6 Hz range with different phase relationships that could be altered experimentally (e.g.…”

Section: Homogeneity Of Sympathetic Drivesmentioning

confidence: 99%

Coherence between the sympathetic drives to relaxed and contracting muscles of different limbs of human subjects.

Wallin

Burke

Gandevia

1992

The Journal of Physiology

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SUMMARY1. This study was undertaken to quantify the simultaneous sympathetic drives to muscles in the two legs of human subjects, and to elucidate the extent to which a common drive determines sympathetic outflow to different limbs at rest, during apnoea and during voluntary contractions.2. Sympathetic efferent activity was recorded simultaneously from fascicles of both peroneal nerves, innervating the pretibial flexor muscles. At rest the similarity was quantified for a sample of records by manual measurement of equivalent bursts in the two recordings, and for all records by cross-correlation and power spectral analysis of the two recordings. During contractions, only the latter method was used.3. At rest the correlation coefficient for the relationship between the burst amplitudes for the two recordings was 0-72 (S.D. 0-1). For the same sequences, the computed coherence between the two recordings was 85-6 % (S.D. 67 %) at the cardiac period. There was a statistically significant linear relationship between these two measures of similarity, and this was stronger when data from sequences recorded during apnoea were included in the analysis. At rest the mean difference in coherence between consecutive sequences with no intervening manoeuvre (apnoea, contraction, change in recording site) was 4-2 % (S.D. 4.3 %). In only two of forty-nine such instances was the difference in coherence > 10 %.4. Apnoea at end-expiration increased the amplitude and frequency of sympathetic bursts and increased the similarity between the two recordings. The correlation coefficients increased from a mean of 0-72 at rest to 0-89 during apnoea. Coherence increased from a mean of 82-1 % at rest to 91-9 % during apnoea.5. On the right side, graded voluntary contractions were performed at 5, 10, 20 or 30 % maximal force using the muscle innervated by the fascicle from which the recording was made. The coherence between the recordings made from the right and left legs decreased by > 10% at each contraction level. Pooling the data for all contractions, there was a significant decrease in power at the cardiac frequency in the

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Relationships between activity of sympathetic nerve pairs: phase and coherence

Cited by 57 publications

References 0 publications

Medullary substrate and differential cardiovascular responses during stimulation of specific acupoints

Medullary substrate and differential cardiovascular responses during stimulation of specific acupoints

Sympathetic nerve regulation to heating is altered in senescent rats

Coherence between the sympathetic drives to relaxed and contracting muscles of different limbs of human subjects.

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