Document Detail

Modification of the reflex response to stimulation of carotid sinus baroreceptors during and following stimulation of the hypothalamic defence area in the cat.
MedLine Citation:
PMID:  5559629     Owner:  NLM     Status:  MEDLINE    
1. The effects of stimulation of the hypothalamic defence area on carotid sinus baroreceptor reflexes have been investigated by examining the cardiovascular responses to a 15 sec period of increased pressure within the vascularly isolated carotid sinus before, during, and immediately following a 25 sec period of hypothalamic stimulation.2. Identification of the hypothalamic defence area was based on the occurence of atropine-sensitive muscle vasodilatation. Electrode positions were confirmed by histological examination.3. During hypothalamic stimulation the reflex fall in blood pressure resulting from a rise in sinus pressure was found to be undiminished whether sinus pressure was raised at the onset or at the 10th sec of hypothalamic stimulation.4. By contrast, in at least half the cats in which a reflex bradycardia could be evoked from the sinus, this bradycardia was largely if not completely suppressed during hypothalamic stimulation. This suppression of reflex bradycardia occurred when sinus pressure was raised at the onset as well as at the 10th sec of stimulation.5. During the first 5 sec after hypothalamic stimulation the hypotensive response to an increase in carotid sinus pressure was much reduced; on the other hand the reduction in heart rate was exaggerated, sometimes to a very marked degree.6. The results suggest that stimulation of the hypothalamic defence area can modify baroreceptor reflexes and that this modification can include selective alterations in the various components of the reflex response.
P W Humphreys; N Joels; R M McAllen
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Journal of physiology     Volume:  216     ISSN:  0022-3751     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  1971 Jul 
Date Detail:
Created Date:  1971-09-23     Completed Date:  1971-09-23     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  461-82     Citation Subset:  IM    
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MeSH Terms
Aorta / innervation
Blood Pressure
Carotid Sinus / innervation*
Electric Stimulation
Heart Rate
Hypothalamus / physiology*
Muscles / blood supply
Pressoreceptors / physiology*
Vascular Resistance

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

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