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. 1978 Jan;274:621–637. doi: 10.1113/jphysiol.1978.sp012170

Human muscle nerve sympathetic activity at rest. Relationship to blood pressure and age

G Sundlöf 1, B G Wallin 1
PMCID: PMC1282513  PMID: 625012

Abstract

1. Recordings of multi-unit sympathetic activity were made from median or peroneal muscle nerve fascicles in thirty-three healthy subjects, resting in recumbent position. Simultaneous recordings of intra-arterial blood pressure were made in seventeen subjects. The neural activity, quantified by counting the number of pulse synchronous sympathetic bursts in the mean voltage neurogram (burst incidence), was plotted against the arterial blood pressure level and the age of the subjects. The effects of spontaneous temporary blood pressure fluctuations were studied by correlating different pressure parameters of individual heart beats to the probability of occurrence of a sympathetic burst and to the amplitude of the occurring burst.

2. Between different subjects there were marked differences in burst incidence, from less than 10 to more than 90 bursts/100 heart beats. No correlation was found to interindividual differences in the arterial blood pressure level but there was a slight tendency for increasing burst incidence with increasing age.

3. Irrespective of the magnitude of the burst incidence, the bursts always occurred more frequently during spontaneous transient blood pressure reductions than during transient increases in blood pressure. When, for each heart cycle, the occurrence of a sympathetic burst was correlated with different blood pressure parameters there was regularly a close negative correlation to diastolic pressure, a low correlation to systolic and an intermediary negative correlation to mean blood pressure. There was a positive correlation to pulse pressure and to pulse interval.

4. When measured for individual heart beats, not only the occurrence but also the mean voltage amplitude of the sympathetic bursts tended to increase with decreasing diastolic pressure.

5. In a given subject when comparing heart beats with the same diastolic pressure, the occurrence as well as the amplitude of the sympathetic bursts was higher for heart beats occurring during falling than for heart beats occurring during rising blood pressure. For a given change in diastolic blood pressure, sympathetic activity changed more if pressure was falling than if it was rising.

6. The findings suggest that the sympathetic outflow is modulated by arterial baroreflex mechanisms and that transient variations in the strength of the activity are, to a large extent, determined by diastolic blood pressure fluctuations. The intimate correlation with `dynamic' variations in blood pressure and the absence of correlation to the `static' blood pressure level suggests that the sympathetic outflow to skeletal muscles is of importance for buffering acute blood pressure changes but has little influence on the long term blood pressure level. The difference in reflex sensitivity between falling and rising pressure indicates that acute blood pressure decreases may be buffered more efficiently than acute blood pressure increases.

7. In twenty-seven subjects baroreflex latency was calculated from the QRS-complexes in the e.c.g. to the appropriate systolic inhibition in the sympathetic activity. When recording in the peroneal nerve, the latency ranged between 1·16 and 1·49 sec and there was a positive correlation with the height of the subjects. It is suggested that such latency measurements may be used clinically to evaluate conduction in sympathetic fibres.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. ALLWOOD M. J. Blood flow in the foot and calf in the elderly; a comparison with that in young adults. Clin Sci. 1958;17(2):331–338. [PubMed] [Google Scholar]
  2. Aars H. Aortic baroreceptor activity in normal and hypertensive rabbits. Acta Physiol Scand. 1968 Mar;72(3):298–309. doi: 10.1111/j.1748-1716.1968.tb03851.x. [DOI] [PubMed] [Google Scholar]
  3. Amery A., Bossaert H., Verstraete M. Muscle blood flow in normal and hypertensive subjects. Influence of age, exercise, and body position. Am Heart J. 1969 Aug;78(2):211–216. doi: 10.1016/0002-8703(69)90010-6. [DOI] [PubMed] [Google Scholar]
  4. Bader H. Dependence of wall stress in the human thoracic aorta on age and pressure. Circ Res. 1967 Mar;20(3):354–361. doi: 10.1161/01.res.20.3.354. [DOI] [PubMed] [Google Scholar]
  5. Bjurstedt H., Rosenhamer G., Tydén G. Cardiovascular responses to changes in carotid sinus transmural pressure in man. Acta Physiol Scand. 1975 Aug;94(4):497–505. doi: 10.1111/j.1748-1716.1975.tb05909.x. [DOI] [PubMed] [Google Scholar]
  6. Burke D., Sundlöf G., Wallin G. Postural effects on muscle nerve sympathetic activity in man. J Physiol. 1977 Nov;272(2):399–414. doi: 10.1113/jphysiol.1977.sp012051. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Delius W., Hagbarth K. E., Hongell A., Wallin B. G. General characteristics of sympathetic activity in human muscle nerves. Acta Physiol Scand. 1972 Jan;84(1):65–81. doi: 10.1111/j.1748-1716.1972.tb05158.x. [DOI] [PubMed] [Google Scholar]
  8. James J. E., Daly M. de B. Comparison of the reflex vasomotor responses to separate and combined stimulation of the carotid sinus and aortic arch baroreceptors by pulsatile and non-pulsatile pressures in the dog. J Physiol. 1970 Aug;209(2):257–293. doi: 10.1113/jphysiol.1970.sp009165. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. James J. E. The responses of aortic arch and right subclavian baroreceptors to changes of non-pulsatile pressure and their modification by hypothermia. J Physiol. 1971 Apr;214(2):201–223. doi: 10.1113/jphysiol.1971.sp009428. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. KEZDI P. Mechanism of the carotid sinus in experimental hypertension. Circ Res. 1962 Jul;11:145–152. doi: 10.1161/01.res.11.1.145. [DOI] [PubMed] [Google Scholar]
  11. Katona P. G., Barnett G. O. Central origin of asymmetry in the carotid sinus reflex. Ann N Y Acad Sci. 1969 Apr 21;156(2):779–786. doi: 10.1111/j.1749-6632.1969.tb14013.x. [DOI] [PubMed] [Google Scholar]
  12. Kendrick E., Oberg B., Wennergren G. Vasoconstrictor fibre discharge to skeletal muscle, kidney, intestine and skin at varying levels of arterial baroreceptor activity in the cat. Acta Physiol Scand. 1972 Aug;85(4):464–476. doi: 10.1111/j.1748-1716.1971.tb05284.x. [DOI] [PubMed] [Google Scholar]
  13. Levison W. H., Barnett G. O., Jackson W. D. Nonlinear analysis of the baroreceptor reflex system. Circ Res. 1966 Jun;18(6):673–682. doi: 10.1161/01.res.18.6.673. [DOI] [PubMed] [Google Scholar]
  14. MCCUBBIN J. W., GREEN J. H., PAGE I. H. Baroceptor function in chronic renal hypertension. Circ Res. 1956 Mar;4(2):205–210. doi: 10.1161/01.res.4.2.205. [DOI] [PubMed] [Google Scholar]
  15. Oberg B. Overall cardiovascular regulation. Annu Rev Physiol. 1976;38:537–570. doi: 10.1146/annurev.ph.38.030176.002541. [DOI] [PubMed] [Google Scholar]
  16. Pelletier C. L., Clement D. L., Shepherd J. T. Comparison of afferent activity of canine aortic and sinus nerves. Circ Res. 1972 Oct;31(4):557–568. doi: 10.1161/01.res.31.4.557. [DOI] [PubMed] [Google Scholar]
  17. Pickering T. G., Gribbin B., Sleight P. Comparison of the reflex heart rate response to rising and falling arterial pressure in man. Cardiovasc Res. 1972 May;6(3):277–283. doi: 10.1093/cvr/6.3.277. [DOI] [PubMed] [Google Scholar]
  18. Resnicoff S. A., Harris J. P., Hampsey J. P., Schwartz S. I. Effects of sinus nerve stimulation on arterial resistance and flow patterns of specific vascular beds. Surgery. 1969 Oct;66(4):755–761. [PubMed] [Google Scholar]
  19. SCHER A. M., YOUNG A. C. Servoanalysis of carotid sinus reflex effects on peripheral resistance. Circ Res. 1963 Feb;12:152–162. doi: 10.1161/01.res.12.2.152. [DOI] [PubMed] [Google Scholar]
  20. Schmidt R. M., Kumada M., Sagawa K. Cardiovascular responses to various pulsatile pressures in the carotid sinus. Am J Physiol. 1972 Jul;223(1):1–7. doi: 10.1152/ajplegacy.1972.223.1.1. [DOI] [PubMed] [Google Scholar]
  21. Spickler J. W., Kezdi P. Dynamic response characteristics of carotid sinus baroreceptors. Am J Physiol. 1967 Feb;212(2):472–476. doi: 10.1152/ajplegacy.1967.212.2.472. [DOI] [PubMed] [Google Scholar]
  22. Stegemann J., Busert A., Brock D. Influence of fitness on the blood pressure control system in man. Aerosp Med. 1974 Jan;45(1):45–48. [PubMed] [Google Scholar]
  23. Stegemann J., Tibes U. Der Einfluss von Amplitude, Frequenz und Mittelwert sinusförmiger Reizdrucke an den Pressoreceptoren auf den arteriellen Mitteldruck des Hundes. Pflugers Arch. 1969;305(3):219–228. doi: 10.1007/BF00587276. [DOI] [PubMed] [Google Scholar]
  24. Sundlöf G., Wallin B. G. The variability of muscle nerve sympathetic activity in resting recumbent man. J Physiol. 1977 Nov;272(2):383–397. doi: 10.1113/jphysiol.1977.sp012050. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Thron H. L., Brechmann W., Wagner J., Keller K. Quantitative Untersuchungen über die Bedeutung der Gefässdehnungsreceptoren im Rahmen der Kreislaufhomoiostase beim wachen Menschen. I. Das Verhalten von arteriellem Blutdruck und Herzfrequenz bei abgestufter Veränderung des transmuralen Blutdrucks im Bereich des Carotissinus. Pflugers Arch Gesamte Physiol Menschen Tiere. 1967;293(1):68–99. [PubMed] [Google Scholar]
  26. Wallin B. G., Delius W., Hagbarth K. E. Comparison of sympathetic nerve activity in normotensive and hypertensive subjects. Circ Res. 1973 Jul;33(1):9–21. doi: 10.1161/01.res.33.1.9. [DOI] [PubMed] [Google Scholar]
  27. Wallin B. G., Delius W., Sundlöf G. Human muscle nerve sympathetic activity in cardiac arrhythmias. Scand J Clin Lab Invest. 1974 Dec;34(4):293–300. doi: 10.3109/00365517409049883. [DOI] [PubMed] [Google Scholar]
  28. Wallin B. G., Sundlöf G., Delius W. The effect of carotid sinus nerve stimulation on muscle and skin nerve sympathetic activity in man. Pflugers Arch. 1975 Jul 21;358(2):101–110. doi: 10.1007/BF00583921. [DOI] [PubMed] [Google Scholar]

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