J Clin Invest. 1991 Jun;87(6):1953-7. doi: 10.1172/JCI115221.

Interaction of baroreceptor and chemoreceptor reflex control of sympathetic nerve activity in normal humans.

The Journal of clinical investigation

V K Somers, A L Mark, F M Abboud

PMID: 2040688 PMCID: PMC296947 DOI: 10.1172/JCI115221
Free PMC Article

Abstract

Animal studies have demonstrated that activation of the baroreflex by increases in arterial pressure inhibits cardiovascular and ventilatory responses to activation of peripheral chemoreceptors (PC) with hypoxia. In this study, we examined the influences of baroreflex activation on the sympathetic response to stimulation of PC and central chemoreceptors in humans. PC were stimulated by hypoxia (10% O2/90% N2) (n = 6) and central chemoreceptors by hypercapnia (7% CO2/93% O2) (n = 6). Responses to a cold pressor stimulus were also obtained as an internal reflex control to determine the selectivity of the interactive influence of baroreflex activation. Baroreflex activation was achieved by raising mean blood pressure by greater than 10 mmHg with intravenous infusion of phenylephrine (PE). Sympathetic nerve activity (SNA) to muscle was recorded from a peroneal nerve (microneurography). During hypoxia alone, SNA increased from 255 +/- 92 to 354 +/- 107 U/min (P less than 0.05). During PE alone, mean blood pressure increased and SNA decreased to 87 +/- 45 U/min (P less than 0.05). With hypoxia during baroreflex activation with PE, SNA did not increase (50 +/- 23 U/min). During hypercapnia alone, SNA increased from 116 +/- 39 to 234 +/- 72 U/min (P less than 0.01). Hypercapnia during baroreflex activation with PE increased SNA from 32 +/- 25 U/min during PE alone to 61 +/- 26 U/min during hypercapnia and PE (P less than 0.05). Like hypercapnia (but unlike hypoxia) the cold pressor test also increased SNA during PE. We conclude that baroreflex activation selectively abolishes the SNA response to hypoxia but not to hypercapnia or the cold pressor test. The inhibitory interaction of the baroreflex and the peripheral chemoreflex may be explained by convergence of baroreceptor and peripheral chemoreceptor afferents on neurons in the medulla.

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References

1. N Engl J Med. 1970 Apr 9;282(15):823-9 - PubMed
2. Ann N Y Acad Sci. 1963 Jun 24;109:756-71 - PubMed
3. N Engl J Med. 1971 Nov;285(20):1105-11 - PubMed
4. J Physiol. 1972 Jun;223(2):525-48 - PubMed
5. J Appl Physiol. 1973 Dec;35(6):903-13 - PubMed
6. J Clin Invest. 1974 May;53(5):1226-36 - PubMed
7. Circ Res. 1975 Feb;36(2):270-6 - PubMed
8. J Appl Physiol. 1975 Sep;39(3):411-6 - PubMed
9. Am J Physiol. 1976 Jan;230(1):19-24 - PubMed
10. Physiol Rev. 1979 Oct;59(4):919-57 - PubMed
11. Circ Res. 1985 Sep;57(3):461-9 - PubMed
12. J Clin Invest. 1985 Dec;76(6):2265-74 - PubMed
13. Hypertension. 1988 Jun;11(6 Pt 2):608-12 - PubMed
14. J Appl Physiol (1985). 1989 Nov;67(5):2095-100 - PubMed
15. J Appl Physiol (1985). 1989 Nov;67(5):2101-6 - PubMed
16. J Appl Physiol (1985). 1990 Feb;68(2):678-86 - PubMed
17. Circ Res. 1970 Aug;27(2):259-76 - PubMed

Substances

• Phenylephrine

MeSH terms

• Adult
• Chemoreceptor Cells / physiology
• Cold Temperature
• Electrophysiology
• Hemodynamics
• Humans
• Hypercapnia / physiopathology
• Hypoxia / physiopathology
• Phenylephrine / pharmacology
• Pressoreceptors / physiology
• Reflex / physiology
• Respiration
• Sympathetic Nervous System / physiology

Publication Types

• Journal Article
• Research Support, U.S. Gov't, P.H.S.

Grant support

• HL-14388/HL/NHLBI NIH HHS/United States
• HL-24962/HL/NHLBI NIH HHS/United States

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