Document Detail

Effects of nitric oxide inhibition on thermoregulation during exercise in the horse.
MedLine Citation:
PMID:  9100938     Owner:  NLM     Status:  MEDLINE    
We investigated the role of NO in the control of thermoregulation. We measured sweating rate and body temperatures (core, rectal and skin) in five thoroughbred horses during exercise of variable intensity on a high-speed treadmill. A standard exercise test (SET) consisting of three canters (8 m s-1), with walking and trotting between each canter, was performed twice, in random order, by each horse and N omega-nitro-L-arginine methyl ester (L-NAME; 20 mg ml-1), a competitive inhibitor of nitric oxide synthase (NOS), was infused into the central circulation after the first canter in the test SET only. L-Arginine (200 mg ml-1), a substrate of NOS, was injected after the second canter in both control and test SETs. L-NAME significantly (p < 0.05) reduced the sweating rate measured on the neck (31.6 +/- 6.4 versus 9.7 +/- 4.2 g/min/m2) and rump (14.7 +/- 5.2 versus 4.8 +/- 1.6 g/min/m2) while raising the core temperature (39.7 +/- 0.2 versus 40.6 +/- 0.7 degrees C, p < 0.05) during the second canter. In the third canter, sweating rate had increased after giving L-arginine during the test SET, but had not returned to levels measured at similar times during the control SET. Core, rectal and skin temperatures continued to rise and were significantly higher than control levels, despite giving L-arginine. The results show that inhibition of NO production reduces sweating rate in the horse during exercise thereby inducing a rise in body temperatures.
P C Mills; C M Scott; D J Marlin
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Annals of the New York Academy of Sciences     Volume:  813     ISSN:  0077-8923     ISO Abbreviation:  Ann. N. Y. Acad. Sci.     Publication Date:  1997 Mar 
Date Detail:
Created Date:  1997-05-01     Completed Date:  1997-05-01     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  7506858     Medline TA:  Ann N Y Acad Sci     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  591-9     Citation Subset:  IM    
Equine Centre, Animal Health Trust, Newmarket, Suffolk, United Kingdom.
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MeSH Terms
Body Temperature / drug effects
Body Temperature Regulation
Enzyme Inhibitors / pharmacology
Horses / physiology*
NG-Nitroarginine Methyl Ester / pharmacology
Nitric Oxide / physiology*
Nitric Oxide Synthase / antagonists & inhibitors
Physical Exertion*
Skin Physiological Phenomena
Sweating / drug effects,  physiology
Reg. No./Substance:
0/Enzyme Inhibitors; 10102-43-9/Nitric Oxide; 50903-99-6/NG-Nitroarginine Methyl Ester; EC Oxide Synthase

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

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