Journal article
Impairment of cardiopulmonary baroreflexes during the newborn period
American journal of physiology. Heart and circulatory physiology, Vol.268(3), pp.H1343-H1351
03/01/1995
DOI: 10.1152/ajpheart.1995.268.3.H1343
PMID: 7900887
Abstract
The present study was designed to characterize the maturation of cardiopulmonary reflex control of renal sympathetic nerve activity (RSNA) independent of influences from the arterial baroreflex. Studies were conducted in conscious newborn lambs (3- to 7-days-old) (n = 16) and older lambs (6- to 8-wk-old) (n = 18). All animals underwent either sinoaortic denervation (SAD) or a sham procedure. Hemodynamic, humoral, neural, and renal responses to volume expansion (6% Dextran 70, 0.7 ml.kg-1.min-1 x 60 min) were recorded. Volume expansion resulted in a significant decrease (P < 0.05) in RSNA in intact newborn (-28.1 +/- 5.3% change from control) and older lambs (-19.4 +/- 10.1%). SAD totally abolished the sympathetic inhibition seen with volume expansion in newborn lambs (-3.6 +/- 5.7%) but not in older lambs (-25.6 +/- 8.4%). Right atrial pressure increased in a similar fashion in both newborn (intact: 5.6 +/- 0.5 mmHg; SAD: 6.1 +/- 0.8 mmHg) and older lambs (intact: 5.2 +/- 0.9 mmHg; SAD: 5.3 +/- 0.9 mmHg) and was not altered by SAD. The reflex bradycardia seen with volume expansion in newborn lambs was blocked by SAD. The present study demonstrates that, during the newborn period, the RSNA and heart rate responses to volume expansion are dependent mainly on the integrity of the arterial baroreflex. Furthermore, these studies suggest that cardiopulmonary reflex control of RSNA in response to volume expansion is impaired early in life and increases with maturation.
Details
- Title: Subtitle
- Impairment of cardiopulmonary baroreflexes during the newborn period
- Creators
- David C Merrill - University of Iowa Hospitals and ClinicsOliva J McWeeny - University of IowaJeffrey L Segar - University of IowaJean E Robillard - University of Iowa
- Resource Type
- Journal article
- Publication Details
- American journal of physiology. Heart and circulatory physiology, Vol.268(3), pp.H1343-H1351
- DOI
- 10.1152/ajpheart.1995.268.3.H1343
- PMID
- 7900887
- ISSN
- 0363-6135
- eISSN
- 1522-1539
- Language
- English
- Date published
- 03/01/1995
- Academic Unit
- Molecular Physiology and Biophysics; Nephrology, Dialysis and Transplantation; Stead Family Department of Pediatrics; Medicine Administration
- Record Identifier
- 9984774211502771
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