Document Detail

Role of brain angiotensin II on somatosensory-induced antinatriuresis in hypertensive rats.
MedLine Citation:
PMID:  11408379     Owner:  NLM     Status:  MEDLINE    
The aim of this investigation was to compare the contribution of brain angiotensin II in mediating the transmission of a somatosensory stimulus within the brain to generate a renal sympathetic nerve-dependent antidiuresis and antinatriuresis in normotensive Wistar rats and stroke-prone spontaneously hypertensive rats (SHRSP). In anesthetized Wistar rats, stimulation of somatosensory receptors by subcutaneous capsaicin increased blood pressure by 9%, had no effect on renal hemodynamics, but decreased urinary flow and sodium excretion by 30% to 40%. These antidiuretic and antinatriuretic, but not blood pressure, responses were absent after intracerebroventricular losartan administration to block angiotensin II type 1 receptors. By contrast, in the SHRSP, although subcutaneous capsaicin raised blood pressure and renal blood flow, neither glomerular filtration rate, urinary flow, nor sodium excretion changed, and this pattern of responses was unaffected after intracerebroventricular losartan. However, an intracerebroventricular infusion of angiotensin II increased basal blood pressure and fluid output, and the capsaicin challenge elicited vasopressor, antidiuretic, and antinatriuretic responses similar in magnitude to those observed in the Wistar rats. The capsaicin challenge in the SHRSP also caused a slowly developing, long-lasting fall in blood pressure and fluid excretion. These findings show that angiotensin II is a necessary component in the somatorenal reflex in normotensive rats but that endogenous angiotensin II is unable to exert this role in SHRSP.
C Huang; E J Johns
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Hypertension     Volume:  37     ISSN:  1524-4563     ISO Abbreviation:  Hypertension     Publication Date:  2001 Jun 
Date Detail:
Created Date:  2001-06-15     Completed Date:  2001-08-02     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7906255     Medline TA:  Hypertension     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1369-74     Citation Subset:  IM    
Department of Physiology, The Medical School, Birmingham, UK.
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MeSH Terms
Angiotensin II / pharmacology,  physiology*
Antihypertensive Agents / pharmacology
Blood Pressure / drug effects
Brain / physiology*
Capsaicin / pharmacology
Diuresis / drug effects
Hypertension / physiopathology*,  urine
Kidney / blood supply,  innervation,  physiopathology*
Losartan / pharmacology
Natriuresis / drug effects*
Neural Pathways / physiopathology
Rats, Inbred SHR
Rats, Wistar
Renal Circulation / drug effects
Sodium / urine
Somatosensory Cortex / physiology
Sympathetic Nervous System
Reg. No./Substance:
0/Antihypertensive Agents; 11128-99-7/Angiotensin II; 114798-26-4/Losartan; 404-86-4/Capsaicin; 7440-23-5/Sodium

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