Document Detail


Preglomerular and postglomerular resistance responses to different levels of sympathetic activation by hypoxia.
MedLine Citation:
PMID:  11752018     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This study investigated the effects of graded reflex increases in renal sympathetic nerve activity (RSNA) on renal preglomerular and postglomerular vascular resistances. With the use of hypoxia to reflexly elicit increases in RSNA without affecting mean arterial pressure, renal function and stop-flow pressures were measured in three groups of rabbits before and after exposure to room air and moderate (14% O2) or severe (10% O2) hypoxia. Moderate and severe hypoxia increased RSNA, primarily by increasing the amplitude of the sympathetic bursts rather than their frequency. RSNA amplitude increased by 20 +/- 6% (P < 0.05) and 60 +/- 16% (P < 0.05), respectively. Moderate hypoxia decreased estimated renal blood flow (ERBF; 26 +/- 7%; P = 0.07), whereas estimated glomerular capillary pressure (32 +/- 1 versus 34 +/- 1 mmHg; P < 0.05) and filtration fraction (FF; P < 0.01) increased. In response to moderate hypoxia, calculated preglomerular (approximately 20%) and postglomerular (approximately 70%) resistance both increased, but only the increase in postglomerular resistance was significant (P < 0.05). In contrast, severe hypoxia decreased ERBF (56 +/- 8%; P < 0.01), GFR (55 +/- 9%; P < 0.001), and glomerular capillary pressure (32 +/- 1 versus 29 +/- 1 mmHg; P < 0.001), with no change in FF, reflecting similar preglomerular (approximately 240%; P < 0.05) and postglomerular ( approximately 250%; P < 0.05) contributions to the vasoconstriction and a decrease in calculated K(f) (P < 0.05). These results provide evidence that reflexly induced increases in RSNA amplitude may differentially control preglomerular and postglomerular vascular resistances.
Authors:
Kate M Denton; Amany Shweta; Warwick P Anderson
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of the American Society of Nephrology : JASN     Volume:  13     ISSN:  1046-6673     ISO Abbreviation:  J. Am. Soc. Nephrol.     Publication Date:  2002 Jan 
Date Detail:
Created Date:  2001-12-25     Completed Date:  2002-02-25     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9013836     Medline TA:  J Am Soc Nephrol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  27-34     Citation Subset:  IM    
Affiliation:
Department of Physiology, Monash University, Clayton, Victoria, Australia. k.denton@med.monash.edu.au
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MeSH Terms
Descriptor/Qualifier:
Animals
Anoxia / physiopathology*
Blood Pressure / drug effects
Capillaries / physiopathology
Dose-Response Relationship, Drug
Kidney Glomerulus / innervation*,  physiopathology*
Male
Oxygen / administration & dosage,  pharmacology
Rabbits
Reference Values
Renal Circulation / drug effects
Sympathetic Nervous System / physiopathology*
Vascular Resistance* / drug effects
Chemical
Reg. No./Substance:
7782-44-7/Oxygen

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


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