Document Detail

Influence of dietary sodium on the blood pressure and renal sympathetic nerve activity responses to intracerebroventricular angiotensin II and angiotensin III in anaesthetized rats.
MedLine Citation:
PMID:  19880539     Owner:  NLM     Status:  MEDLINE    
The regulation of blood pressure and sympathetic outflow by the brain renin-angiotensin system in animals subjected to raised or lowered dietary Na(+) intake is unclear. This study compared the mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA) responses to intracerebroventricular (i.c.v.) infusion of angiotensin II (AngII) and III (AngIII) before and after peripheral V(1) receptor blockade (V(1)B) in alpha-chloralose-urethane-anaesthetized rats fed a low (0.03%, LNa(+)), normal (0.3%, NNa(+)) or high Na(+) diet (3.0%, HNa(+)) from 4 to 11 weeks of age. The rise in MAP 2 min post AngII i.c.v. was greater in HNa(+) (14 +/- 3 mmHg) versus LNa(+) (8 +/- 1 mmHg, P < 0.05) and after AngIII i.c.v. in HNa(+) (14 +/- 3 mmHg) versus NNa(+) (6 +/- 1 mmHg, P < 0.05) and LNa(+) (7 +/- 1 mmHg, P < 0.05). The MAP responses to AngII and AngIII i.c.v. were abolished after V(1)B in LNa(+), but were only attenuated in HNa(+). In NNa(+), V(1)B blunted the MAP responses to AngII and abolished those to AngIII. The MAP remained elevated 30 min after AngII in all groups, but returned to baseline levels 15 min after AngIII in NNa(+) and HNa(+) (P < 0.01). Twenty minutes after i.c.v. AngII, RSNA rose above baseline in HNa(+) (112 +/- 1%), a response not observed in the LNa(+) and NNa(+) groups. Twenty minutes post AngIII i.c.v., RSNA was elevated in both HNa (109 +/- 2%) and NNa(+) (109 +/- 2%). After V(1)B, RSNA rose only in the HNa(+) group 15 min post AngIII infusion (109 +/- 1%). Together, these findings: (1) suggest that HNa(+) intake augments the MAP and RSNA responses to i.c.v. AngII and AngIII; (2) highlight an important role for peripheral V(1) receptors during these responses; and (3) differentiate the effects of AngII and AngIII on blood pressure and RSNA.
Belinda L Houghton; Chunlong Huang; Edward J Johns
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-10-30
Journal Detail:
Title:  Experimental physiology     Volume:  95     ISSN:  1469-445X     ISO Abbreviation:  Exp. Physiol.     Publication Date:  2010 Feb 
Date Detail:
Created Date:  2010-02-12     Completed Date:  2010-05-06     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9002940     Medline TA:  Exp Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  282-95     Citation Subset:  IM    
Department of Physiology, Windle Building, University College Cork, College Road, Cork, Republic of Ireland.
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MeSH Terms
Anesthesia, General
Angiotensin II / administration & dosage*
Angiotensin III / administration & dosage*
Blood Pressure / drug effects,  physiology*
Cerebral Ventricles / drug effects,  physiology*
Infusions, Parenteral
Kidney / drug effects,  innervation,  physiology*
Rats, Sprague-Dawley
Renin-Angiotensin System / drug effects,  physiology
Sodium, Dietary / metabolism*
Sympathetic Nervous System / physiology*
Reg. No./Substance:
0/Sodium, Dietary; 11128-99-7/Angiotensin II; 12687-51-3/Angiotensin III

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

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