Document Detail


H2O2 increases sheep tracheal blood flow, permeability, and vascular response to luminal capsaicin.
MedLine Citation:
PMID:  9049746     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Exogenous hydrogen peroxide (H2O2) causes airway epithelial damage in vitro. We have studied the effects of luminal H2O2 in the sheep trachea in vivo on tracheal permeability to low-molecular-weight hydrophilic (technetium-99m-labeled diethylenetriamine pentaacetic acid; 99mTc-DTPA) and lipophilic ([14C]antipyrine; [14C]AP) tracers and on the tracheal vascular response to luminal capsaicin, which stimulates afferent nerve endings. A tracheal artery was perfused, and tracheal venous blood was collected. H2O2 exposure (10 mM) reduced tracheal potential difference (-42.0 +/- 6.4 mV) to zero. It increased arterial and venous flows (56.7 +/- 6.1 and 57.3 +/- 10.0%, respectively; n = 5, P < 0.01, paired t-test) but not tracheal lymph flow (unstimulated flow 5.0 +/- 1.2 microliters.min-1.cm-1, n = 4). During H2O2 exposure, permeability to 99mTc-DTPA increased from -2.6 to -89.7 x 10(-7) cm/s (n = 5, P < 0.05), whereas permeability to [14C]AP (-3,312.6 x 10(-7) cm/s, n = 4) was not altered significantly (-2,565 x 10(-7) cm/s). Luminal capsaicin (10 microM) increased tracheal blood flow (10.1 +/- 4.1%, n = 5) and decreased venous 99mTc-DTPA concentration (-19.7 +/- 4.0, P < 0.01), and these effects were significantly greater after epithelial damage (28.1 +/- 6.0 and -45.7 +/- 4.3%, respectively, P < 0.05, unpaired t-test). Thus H2O2 increases the penetration of a hydrophilic tracer into tracheal blood and lymph but has less effect on a lipophilic tracer. It also enhances the effects of luminal capsaicin on blood flow and tracer uptake.
Authors:
U M Wells; S Duneclift; J G Widdicombe
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  82     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1997 Feb 
Date Detail:
Created Date:  1997-06-05     Completed Date:  1997-06-05     Revised Date:  2009-09-29    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  621-31     Citation Subset:  IM    
Affiliation:
Department of Physiology, St. George's Hospital Medical School, London, United Kingdom.
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MeSH Terms
Descriptor/Qualifier:
Animals
Capsaicin / pharmacology*
Hydrogen Peroxide / pharmacology*
Permeability / drug effects
Pulmonary Circulation / drug effects*
Sheep
Trachea / drug effects*
Grant Support
ID/Acronym/Agency:
//Wellcome Trust
Chemical
Reg. No./Substance:
404-86-4/Capsaicin; 7722-84-1/Hydrogen Peroxide

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


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