Document Detail

Reflexes from pulmonary arterial baroreceptors in dogs: interaction with carotid sinus baroreceptors.
MedLine Citation:
PMID:  21690195     Owner:  NLM     Status:  MEDLINE    
In contrast to the reflex vasodilatation occurring in response to stimulation of baroreceptors in the aortic arch, carotid sinuses and coronary arteries, stimulation of receptors in the wall of pulmonary arteries results in reflex systemic vasoconstriction. It is rare for interventions to activate only one reflexogenic region, therefore we investigated how these two types of reflexes interact. In anaesthetized dogs connected to cardiopulmonary bypass, reflexogenic areas of the carotid sinuses, aortic arch and coronary arteries and the pulmonary artery were subjected to independently controlled pressures. Systemic perfusion pressure (SPP) measured in the descending aorta (constant flow) provided an index of systemic vascular resistance. In other experiments, sympathetic efferent neural activity was recorded in fibres dissected from the renal nerve (RSNA). Physiological increases in pulmonary arterial pressure (PAP) induced significant increases in SPP (+39.1 ± 10.4 mmHg) and RSNA (+17.6 ± 2.2 impulses s(−1)) whereas increases in carotid sinus pressure (CSP) induced significant decreases in SPP (−42.6 ± 10.8 mmHg) and RSNA (−42.8 ± 18.2 impulses s(−1)) (P < 0.05 for each comparison; paired t test). To examine possible interactions, PAP was changed at different levels of CSP in both studies. With CSP controlled at 124 ± 2 mmHg, the threshold, 'set point' and saturation pressures of the PAP–SPP relationship were higher than those with CSP at 60 ± 1 mmHg; this rightward shift was associated with a significant decrease in the reflex gain. Similarly, increasing CSP produced a rightward shift of the PAP–RSNA relationship, although the effect on reflex gain was inconsistent. Furthermore, the responses to changes in CSP were influenced by setting PAP at different levels; increasing the level of PAP from 5 ± 1 to 33 ± 3 mmHg significantly increased the set point and threshold pressures of the CSP–SPP relationship; the reflex gain was not affected. These results indicate the existence of interaction between pulmonary arterial and carotid sinus baroreceptor reflexes; physiological and pathological states that alter the stimulus to one may alter the reflex responses from the other.
Jonathan P Moore; Roger Hainsworth; Mark J Drinkhill
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't     Date:  2011-06-20
Journal Detail:
Title:  The Journal of physiology     Volume:  589     ISSN:  1469-7793     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  2011 Aug 
Date Detail:
Created Date:  2011-08-16     Completed Date:  2012-05-24     Revised Date:  2013-06-28    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  4041-52     Citation Subset:  IM    
Integrated Physiology Laboratory, Division of Cardiovascular and Neuronal Remodelling, LIGHT, University of Leeds, UK.
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MeSH Terms
Baroreflex / physiology*
Carotid Sinus / metabolism,  physiology*
Perfusion / instrumentation,  methods
Pressoreceptors / metabolism,  physiology*
Pulmonary Artery / metabolism,  physiology*
Vasoconstriction / physiology*
Grant Support
//British Heart Foundation

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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