Document Detail


Blood pressure and heart rate responses to mental stress in spontaneously hypertensive (SHB) and normotensive (WKY) rats on various sodium diets.
MedLine Citation:
PMID:  2858959     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Normotensive (WKY) and hypertensive rats (SHR) were, from 5 to 12 weeks of age, given 'low' (LNa), 'control' and 'high' (HNa) Na diets (0.5, 5 and 50 mmol X 100 g-1 food, respectively, during weekly recordings of body weight, conscious indirect systolic blood pressure (SBP) and heart rate (HR). During the last week, mean arterial pressure (MAP) and HR responses to standardized stress stimuli (air jet) were recorded before and after sequential cardiac nerve blockade. While resting, SBP was about equal in all WKY groups, but it was significantly reduced in SHR-LNa (152 mmHg versus 174 and 178 mmHg in SHR controls and HNa; P less than 0.05). In both LNa groups HR was elevated nearly 25% compared with controls, being in SHR 513 versus 419 bpm (P less than 0.01) and in WKY 489 versus 393 bpm (P less than 0.01). Cardiac nerve blockade indicated that this HR elevation was about equally due to elevations of sympathetic activity and 'intrinsic' pacemaker activity. SHR-LNa also showed attenuated MAP elevations to acute mental stress. There were, however, no significant differences between groups concerning haematocrit or plasma Na-K levels. The results suggest that SHR have a greater salt requirement than WKY, as Na restriction to one-tenth of normal led to a considerable MAP reduction in SHR despite compensatory sympathetic activation, and also to attenuated pressor responses to mental stress. Further, the cardiovascular effects in SHR were much more extensive when on a low-Na diet than when Na intake was increased tenfold above normal.
Authors:
D L Ely; P Friberg; H Nilsson; B Folkow
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Acta physiologica Scandinavica     Volume:  123     ISSN:  0001-6772     ISO Abbreviation:  Acta Physiol. Scand.     Publication Date:  1985 Feb 
Date Detail:
Created Date:  1985-05-20     Completed Date:  1985-05-20     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370362     Medline TA:  Acta Physiol Scand     Country:  SWEDEN    
Other Details:
Languages:  eng     Pagination:  159-69     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Adrenergic alpha-Antagonists / pharmacology
Animals
Blood Pressure* / drug effects
Diet, Sodium-Restricted
Electrolytes / analysis
Heart Rate* / drug effects
Hematocrit
Humans
Male
Phentolamine / pharmacology
Rats
Rats, Inbred SHR
Rats, Inbred WKY
Sodium Chloride / administration & dosage*
Stress, Psychological*
Vagus Nerve / drug effects
Chemical
Reg. No./Substance:
0/Adrenergic alpha-Antagonists; 0/Electrolytes; 50-60-2/Phentolamine; 7647-14-5/Sodium Chloride

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


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