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Ontogeny of baroreflex control of renal sympathetic nerve activity and heart rate. Am J Physiol 1992 Dec;263(6 Pt 2):H1819-26

Date

12/01/1992

Pubmed ID

1481906

DOI

10.1152/ajpheart.1992.263.6.H1819

Scopus ID

2-s2.0-0027093660   54 Citations

Abstract

The purpose of this study was to characterize the developmental changes in baroreflex function during fetal and postnatal life in sheep. Resting mean arterial blood pressure increased significantly from 55 +/- 2 mmHg in fetuses to 86 +/- 3 mmHg in newborn lambs and to 105 +/- 4 mmHg in 4- to 6-wk-old lambs. The sensitivity (gain) of the renal sympathetic nerve activity (RSNA) response to baroreceptor stimulation was greater (P < 0.05) in fetuses (-7.7 +/- 1.9%/mmHg) than in newborn (-2.9 +/- 0.1%/mmHg) and 4- to 6-wk-old lambs (-2.2 +/- 0.2%/mmHg). The threshold and saturation pressures for the baroreflex function curve were lower (P < 0.05) in fetuses (44 +/- 2 and 61 +/- 2 mmHg) than in newborn (59 +/- 4 and 106 +/- 5 mmHg) or 4- to 6-wk-old lambs (78 +/- 5 and 132 +/- 6 mmHg). Similar findings were observed when the heart rate response to baroreceptor stimulation was examined. Additional experiments were performed in newborn and 4- to 6-wk-old lambs to determine whether the rise in arterial blood pressure associated with postnatal maturation contributed to baroreflex resetting. Sustained elevation of arterial blood pressure by 15-20 mmHg for over 90 min did not reset the baroreflex function curve in either newborn or 4- to 6-wk-old lambs.(ABSTRACT TRUNCATED AT 250 WORDS)

Author List

Segar JL, Hajduczok G, Smith BA, Merrill DC, Robillard JE

Author

Jeffrey L. Segar MD Professor in the Pediatrics department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Animals
Animals, Newborn
Arteries
Blood Pressure
Embryonic and Fetal Development
Fetal Blood
Heart Rate
Kidney
Pressoreceptors
Reflex
Rest
Sheep
Sympathetic Nervous System
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