Document Detail

Enhanced myogenic response in the afferent arteriole of spontaneously hypertensive rats.
MedLine Citation:
PMID:  20363886     Owner:  NLM     Status:  MEDLINE    
Spontaneously hypertensive rats (SHRs) have normal glomerular capillary pressure even though renal perfusion pressure is higher, suggesting that preglomerular vessels exhibit abnormally high resistance. This may be due to increased superoxide (O(2)(-)) production, which contributes to the vasoconstriction in hypertension. We tested the hypothesis that the myogenic response of the afferent arteriole (Af-Art) is exaggerated in SHRs because of increased levels of reactive oxygen species (ROS). Single Af-Arts were microdissected from kidneys of SHRs and Wistar-Kyoto (WKY) rats and microperfused in vitro. When perfusion pressure in the Af-Art was increased stepwise from 60 to 140 mmHg, the luminal diameter decreased by 8.4 + or - 2.9% in WKY Af-Arts but fell by 29.3 + or - 5.6% in SHR Af-Arts. To test whether ROS production is enhanced during myogenic response in SHRs, we measured chloromethyl-dichlorodihydrofluorescein diacetate acetyl ester (CM-H(2)DCFDA) florescence before and after increasing intraluminal pressure from 60 to 140 mmHg. Pressure-induced increases in ROS were fourfold greater in SHR Af-Arts compared with WKY Af-Arts (SHR, 48.0 + or - 2.2%; and WKY, 12.2 + or - 0.3%). To test whether O(2)(-) contributes to the myogenic response in SHRs, either the membrane-permeant O(2)(-) scavenger Tempol or the nox2-based NADPH oxidase (NOX2) inhibitor gp91ds-tat were added to the Af-Art lumen and bath and the myogenic response was tested before and after treatment. Both Tempol (10(-4) M) and gp91ds-tat (10(-5) M) significantly attenuated the pressure-induced constriction in SHR Af-Arts but not in WKY Af-Arts. We conclude that 1) pressure-induced constriction is exaggerated in SHR Af-Arts, 2) NOX2-derived O(2)(-) may contribute to the enhanced myogenic response, and 3) O(2)(-) exerts little influence on the myogenic response under normotensive conditions.
YiLin Ren; Martin A D'Ambrosio; Ruisheng Liu; Patrick J Pagano; Jeffrey L Garvin; Oscar A Carretero
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2010-04-02
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  298     ISSN:  1522-1539     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2010 Jun 
Date Detail:
Created Date:  2010-05-20     Completed Date:  2010-06-23     Revised Date:  2014-09-19    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H1769-75     Citation Subset:  IM    
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MeSH Terms
Antioxidants / pharmacology
Arterioles / physiology*
Blood Pressure / physiology
Cyclic N-Oxides / pharmacology
Disease Models, Animal
Hypertension / physiopathology*
Kidney / blood supply*
Membrane Glycoproteins / metabolism
Muscle, Smooth, Vascular / physiology*
NADPH Oxidase / metabolism
Rats, Inbred SHR
Rats, Inbred WKY
Reactive Oxygen Species / metabolism
Regional Blood Flow / physiology
Spin Labels
Superoxides / metabolism
Vasoconstriction / drug effects,  physiology*
Grant Support
Reg. No./Substance:
0/Antioxidants; 0/Cyclic N-Oxides; 0/Membrane Glycoproteins; 0/Reactive Oxygen Species; 0/Spin Labels; 11062-77-4/Superoxides; 2226-96-2/tempol; EC 1.6.-/Cybb protein, rat; EC Oxidase

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

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