Document Detail


Choroidal blood flow compensation in rats for arterial blood pressure decreases is neuronal nitric oxide-dependent but compensation for arterial blood pressure increases is not.
MedLine Citation:
PMID:  20302861     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Choroidal blood flow (ChBF) compensates for changes in arterial blood pressure (ABP) and thereby remains relatively stable within a +/-40 mmHg range of basal ABP in rabbits, humans and pigeons. In the present study, we investigated if ChBF can compensate for increases and decreases in ABP in rats. ChBF was continuously monitored using laser Doppler flowmetry in anesthetized rats, and ABP measured via the femoral artery. At multiple intervals over a 2-4 h period during which ABP varied freely, ChBF and ABP were sampled and the results compiled across rats. We found that ChBF remained near baseline over an ABP range from 40 mmHg above basal ABP (90-100 mmHg) to 40 mmHg below basal ABP, but largely followed ABP linearly below 60 mmHg. Choroidal vascular resistance increased linearly as BP increased above 100 mmHg, and decreased linearly as BP declined from basal to 60 mmHg, but resistance declined no further below 60 mmHg. Inhibition of nitric oxide (NO) formation by either a selective inhibitor of neuronal nitric oxide synthase (NOS) (N(omega)-propyl-L-arginine) or a nonselective inhibitor of both neuronal NOS and endothelial NOS (N(omega)-nitro-l-arginine methyl ester) did not affect compensation above 100 mmHg ABP, but did cause ChBF to linearly follow declines in BP below 90 mmHg. In NOS-inhibited rats, vascular resistance increased linearly with BP above 100 mmHg, but remained at baseline below 90 mmHg. These findings reveal that ChBF in rats, as in rabbits, humans and pigeons, compensates for rises and/or declines in arterial blood pressure so as to remain relatively stable within a physiological range of ABPs. The ChBF compensation for low ABP in rats is dependent on choroidal vasodilation caused by neuronal NO formation but not the compensation for elevated BP, implicating parasympathetic nervous system vasodilation in the ChBF compensation to low ABP.
Authors:
Anton Reiner; Chunyan Li; Nobel Del Mar; Malinda E C Fitzgerald
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2010-03-17
Journal Detail:
Title:  Experimental eye research     Volume:  90     ISSN:  1096-0007     ISO Abbreviation:  Exp. Eye Res.     Publication Date:  2010 Jun 
Date Detail:
Created Date:  2010-05-17     Completed Date:  2010-05-27     Revised Date:  2013-05-29    
Medline Journal Info:
Nlm Unique ID:  0370707     Medline TA:  Exp Eye Res     Country:  England    
Other Details:
Languages:  eng     Pagination:  734-41     Citation Subset:  IM    
Copyright Information:
Copyright 2010 Elsevier Ltd. All rights reserved.
Affiliation:
Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, 855 Monroe Ave., Memphis, TN 38163, USA. areiner@uthsc.edu
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MeSH Terms
Descriptor/Qualifier:
Animals
Arginine / analogs & derivatives,  pharmacology
Blood Flow Velocity / physiology
Blood Pressure / physiology*
Choroid / blood supply*
Homeostasis / physiology*
Laser-Doppler Flowmetry
Male
Nitric Oxide / antagonists & inhibitors,  metabolism*
Nitric Oxide Synthase / antagonists & inhibitors
Nitric Oxide Synthase Type I
Nitroarginine / pharmacology
Rats
Rats, Sprague-Dawley
Regional Blood Flow / physiology
Vascular Resistance / physiology
Grant Support
ID/Acronym/Agency:
EY-05298/EY/NEI NIH HHS; R01 EY005298/EY/NEI NIH HHS; R01 EY005298-23/EY/NEI NIH HHS; R01 EY005298-25/EY/NEI NIH HHS
Chemical
Reg. No./Substance:
0/N(omega)-propargylarginine; 10102-43-9/Nitric Oxide; 2149-70-4/Nitroarginine; 74-79-3/Arginine; EC 1.14.13.39/Nitric Oxide Synthase; EC 1.14.13.39/Nitric Oxide Synthase Type I; EC 1.14.13.39/Nos1 protein, rat
Comments/Corrections

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