Document Detail


NO inhalation reduces pulmonary arterial pressure but not hemorrhage in maximally exercising horses.
MedLine Citation:
PMID:  11717233     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In horses, the exercise-induced elevation of pulmonary arterial pressure (Ppa) is thought to play a deterministic role in exercise-induced pulmonary hemorrhage (EIPH), and thus treatment designed to lower Ppa might reasonably be expected to reduce EIPH. Five Thoroughbred horses were run on a treadmill to volitional fatigue (incremental step test) under nitric oxide (NO; inhaled 80 ppm) and control (N(2), same flow rate as per NO run) conditions (2 wk between trials; order randomized) to test the hypothesis that NO inhalation would reduce maximal Ppa but that this reduction may not necessarily reduce EIPH. Before each investigation, a microtipped pressure transducer was placed in the pulmonary artery 8 cm past the pulmonic valve to monitor Ppa. EIPH severity was assessed via bronchoalveolar lavage (BAL) 30 min postrun. Exercise time did not differ between the two trials (P > 0.05). NO administration resulted in a small but consistent and significant reduction in peak Ppa (N(2), 102.3 +/- 4.4; NO, 98.6 +/- 4.3 mmHg, P < 0.05). In the face of lowered Ppa, EIPH severity was significantly higher in the NO trial (N(2), 22.4 +/- 6.8; NO, 42.6 +/- 15.4 x 10(6) red blood cells/ml BAL fluid, P < 0.05). These findings support the notion that extremely high Ppa may reflect, in part, an arteriolar vasoconstriction that serves to protect the capillary bed from the extraordinarily high Ppa evoked during maximal exercise in the Thoroughbred horse. Furthermore, these data suggest that exogenous NO treatment during exercise in horses may not only be poor prophylaxis but may actually exacerbate the severity of EIPH.
Authors:
C A Kindig; P McDonough; M R Finley; B J Behnke; T E Richardson; D J Marlin; H H Erickson; D C Poole
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  91     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2001 Dec 
Date Detail:
Created Date:  2001-11-21     Completed Date:  2002-02-12     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2674-8     Citation Subset:  IM    
Affiliation:
Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506-5802, USA.
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MeSH Terms
Descriptor/Qualifier:
Administration, Inhalation
Animals
Blood Pressure / drug effects*
Hemorrhage / etiology*,  physiopathology
Horses / physiology*
Lung Diseases / etiology*,  physiopathology
Male
Motor Activity / physiology*
Nitric Oxide / administration & dosage*,  pharmacology
Pulmonary Artery / drug effects*,  physiopathology
Grant Support
ID/Acronym/Agency:
HL-50306/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
10102-43-9/Nitric Oxide

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


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