Variation of sympathetic reflex latency in man

doi:10.1016/0165-1838(87)90018-X

Journal of the Autonomic Nervous System

Volume 21, Issues 2–3, December 1987, Pages 157-165

Journal of the Auton...

https://doi.org/10.1016/0165-1838(87)90018-X Get rights and content

Abstract

Microelectrode recordings of muscle nerve sympathetic activity (MSA) in man have shown a reflex relationship between heart beat and corresponding sympathetic burst, the latency of which is stable at rest and independent of heart rate. In peroneal nerve recordings in 35 healthy subjects this latency was reduced during the Valsalva manoeuvre by 120 ms (mean; range 40–245 ms; P < 0.001) from a mean value at rest of 1300 ms. Slow deep breathing and simulated diving shortened the latency by 60 (P < 0.001) and 80 ms (P < 0.05), respectively. When intrinsic heart rate was induced by i.v. administration of atropine and propranolol, the latency was increased by 70 ms (P < 0.001). A number of other manoeuvres affecting the outflow of MSA did not change the latency. It is suggested that the findings indicate the existence of more than one central pathway involved in the baroreflex regulation of MSA. Alternatively, altered central processing time may follow influence from other receptors in different manoeuvres.

References (18)

C. Borst et al.
Time delays in the human baroreceptor reflex
J. Auton. Nerv. Syst.
(1983)
J. Fagius et al.
Sympathetic reflex latencies and conduction velocities in normal man
J. Neurol. Sci.
(1980)
E. Brown et al.
Circulatory responses to simulated gravitational shifts of blood in man induced by exposure of the body below the iliac crest to subatmospheric pressure
J. Physiol. (London)
(1966)
D.L. Brown et al.
Electrophysiological study of cardiovascular neurons in the rostral ventrolateral medulla in rats
Circ. Res.
(1985)
W. Delius et al.
General characteristics of sympathetic activity in human muscle nerves
Acta Physiol. Scand.
(1972)
W. Delius et al.
Manoeuvres affecting sympathetic outflow in human muscle nerves
Acta Physiol. Scand.
(1972)
D.L. Eckberg et al.
Respiratory modulation of muscle sympathetic and vagal cardiac outflow in man
J. Physiol. (London)
(1985)
Eckberg, D.L., Rea, R.F., Andersson, O.K., Hedner, T., Pernow, J., Lundberg, J. and Wallin, B.G., Baroreflex modulation...
J. Fagius
Muscle nerve sympathetic activity in migraine

There are more references available in the full text version of this article.

Cited by (35)

Sympathetic nerve activity to amputated lower leg in humans: Evidence of altered skin vasoconstrictor discharge
2002, Pain
Transection of a peripheral nerve in the cat is known to cause a regional change in sympathetic impulse pattern. Our aim was to determine whether microneurography can be used to study sympathetic activity in the transected nerve of human amputees, and whether any such activity shows an abnormal pattern similar to that observed in the cat. Seven successful sympathetic recording sessions were performed in the peroneal nerve of four subjects with posttraumatic transtibial leg amputation; one of them was studied on four occasions. Muscle nerve sympathetic activity (MSA) was detected in all four subjects. Skin nerve sympathetic activity (SSA) was found in one patient only, but on three occasions. It was more difficult to obtain high quality sympathetic recordings than for intact nerves, particularly in patients amputated many years before our studies. MSA showed a qualitatively normal pattern at rest and during various manoeuvres. In three recordings from skin nerve fascicles without innervation zone, SSA displayed normal characteristics at room temperature and qualitatively normal responses to arousal stimuli and various manoeuvres. During body cooling there was an abnormal shift in SSA pattern with a reduction in burst duration instead of the increase occurring normally. Cardiac rhythmicity of SSA was more pronounced during body cooling than during body heating. This is also a reversal of the normal pattern. The abnormal SSA pattern during body cooling suggests increased baroreflex regulation of cutaneous vasoconstrictor neurones, similar to the change after nerve transection in the cat. This is the first time that human nerve recordings support the hypothesis of a regional alteration in sympathetic impulse pattern following a nerve lesion. The implications of this phenomenon for pain conditions remains to be explored; our patients did not suffer from phantom or stump pain.
Topical anesthetic before microneurography decreases pain without affecting sympathetic traffic
2000, Autonomic Neuroscience: Basic and Clinical
Pain associated with the microneurography procedure varies among human research volunteers, and may influence baseline sympathetic neural activity. The purpose of this study was to evaluate the efficacy and effects of applying a topical anesthetic prior to microneurography. Ten volunteers underwent microneurography twice, separated by a minimum of 4 weeks. Using a single-blind, randomized cross-over design, EMLA cream (2.5% lidocaine and 2.5% prilocaine in oil emulsion) or an aqueous placebo cream was applied 2 h prior to each session. Subjects rated pain on a scale from 0 (no pain) to 4 (extreme pain). The electrocardiogram, and efferent sympathetic nerve traffic from peroneal nerve muscle fascicles at the popliteal fossa were recorded during a 10-min supine rest period. EMLA cream significantly reduced perception of pain (P<0.05), but did not affect burst reflex latencies from preceding R-waves or total muscle sympathetic nerve traffic (P>0.05). These data show that use of EMLA cream prior to microneurography is innocuous, and do not support the hypothesis that baseline sympathetic traffic is increased by pain or discomfort associated with microneurography.
Inhibition of muscle sympathetic outflow following transcranial cortical stimulation
1998, Journal of the Autonomic Nervous System
The possible contribution of cerebral cortical activity to sympathetic outflow to the muscle vascular bed was assessed in normal human subjects. Muscle sympathetic activity was recorded from motor fascicles of the peroneal nerve in 8 subjects while transcranial magnetic stimulation was applied over the vertex, or unilaterally over the hand area of cortex. By triggering the cortical stimulus from the R-wave of the ECG and introducing delays of 0–600 ms between the trigger and the stimulus, we found that a single cortical stimulus delayed by 200–400 ms caused a pronounced inhibition of one pulse-synchronous sympathetic burst. Stimulation over the vertex was more effective than stimulation over the hand area of cortex. In addition to this inhibition of muscle sympathetic outflow, brain stimulation caused an increase in cutaneous sympathetic activity, both sudomotor (sweating) and vasoconstrictor (decrease in skin blood flow). We suggest that the cerebral cortex may normally suppress muscle sympathetic outflow and speculate that lesions that interrupt this source of inhibition (such as those caused by stroke) may result in an augmented muscle sympathetic outflow.
The discharge behaviour of single sympathetic neurones supplying human sweat glands
1996, Journal of the Autonomic Nervous System
Firing properties of single sudomotor axons were studied via tungsten microelectrodes inserted percutaneously into cutaneous fascicles of the peroneal nerve in awake subjects. Sweating was induced by radiant heat and measured by changes in skin electrical resistance within the innervation territory on the dorsum of the foot. Eight units were classified as sudomotor neurones because spike-triggered averaging revealed a time-locked relationship between the unitary discharge and the subsequent decrease in skin resistance (1.12±0.05 s), but no relationship to skin blood flow (measured by a laser-doppler probe). Sudomotor units usually fired only one (maximum six) spike(s) in a sympathetic burst. The mean firing rate was 0.62 Hz, but instantaneous frequencies above 50 Hz could be generated. R-wave triggered histograms and coherence analysis revealed significant coupling between the firing of three sudomotor neurones and the ECG. Moreover, the firing of four sudomotor neurones showed a weak but significant correlation with the spontaneous fluctuations in cardiac interval, diastolic pressure, or the rate of fall in arterial pressure. We conclude that the discharge of human sudomotor neurones is modulated by baroreceptor input.
Human pupillary light reflex during and after two-fold Valsalva maneuver
1995, Journal of the Autonomic Nervous System
The influence of the Valsalva maneuver on the pupillary light reflex and on the parameters of human pupillogram were studied in 9 normal volunteers (mean age 21.0 years). The consensual pupillary reactions to light were recorded using a infrared-reflecting pupillograph; pupillogram records were processed off-line by a computer system. Latency time increased during the Valsalva maneuver and normalized in the first minute after its end. No significant changes were found in constriction time. Half-redilatation time showed the opposite dynamics of latency time. The amplitude diminished during Valsalva maneuver and in the first minute after it. These results suggest a possible alteration of the autonomic nervous regulation during Valsalva maneuver and especially some changes in parasympathetic outflow to human iris sphincter. The possible effect of prevailing parasympathetic or sympathetic activity on pupillometry parameters during some phases of the Valsalva maneuver and after its end is discussed.
Directional couplings between the respiration and parasympathetic control of the heart rate during sleep and wakefulness in healthy subjects at different ages
2022, Frontiers in Network Physiology

View all citing articles on Scopus

View full text

Research paperVariation of sympathetic reflex latency in man

Abstract

J. Auton. Nerv. Syst.

J. Neurol. Sci.

Circulatory responses to simulated gravitational shifts of blood in man induced by exposure of the body below the iliac crest to subatmospheric pressure

J. Physiol. (London)

Electrophysiological study of cardiovascular neurons in the rostral ventrolateral medulla in rats

Circ. Res.

General characteristics of sympathetic activity in human muscle nerves

Acta Physiol. Scand.

Manoeuvres affecting sympathetic outflow in human muscle nerves

Acta Physiol. Scand.

Respiratory modulation of muscle sympathetic and vagal cardiac outflow in man

J. Physiol. (London)

Muscle nerve sympathetic activity in migraine

Research paper
Variation of sympathetic reflex latency in man