Document Detail


Role played by acid-sensitive ion channels in evoking the exercise pressor reflex.
MedLine Citation:
PMID:  18723762     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The exercise pressor reflex arises from contracting skeletal muscle and is believed to play a role in evoking the cardiovascular responses to static exercise, effects that include increases in arterial pressure and heart rate. This reflex is believed to be evoked by the metabolic and mechanical stimulation of thin fiber muscle afferents. Lactic acid is known to be an important metabolic stimulus evoking the reflex. Until recently, the only antagonist for acid-sensitive ion channels (ASICs), the receptors to lactic acid, was amiloride, a substance that is also a potent antagonist for both epithelial sodium channels as well as voltage-gated sodium channels. Recently, a second compound, A-317567, has been shown to be an effective and selective antagonist to ASICs in vitro. Consequently, we measured the pressor responses to the static contraction of the triceps surae muscles in decerebrate cats before and after a popliteal arterial injection of A-317567 (10 mM solution; 0.5 ml). We found that this ASIC antagonist significantly attenuated by half (P<0.05) the pressor responses to both contraction and to lactic acid injection into the popliteal artery. In contrast, A-317567 had no effect on the pressor responses to tendon stretch, a pure mechanical stimulus, and to a popliteal arterial injection of capsaicin, which stimulated transient receptor potential vanilloid type 1 channels. We conclude that ASICs on thin fiber muscle afferents play a substantial role in evoking the metabolic component of the exercise pressor reflex.
Authors:
Shawn G Hayes; Jennifer L McCord; Jon Rainier; Zhuqing Liu; Marc P Kaufman
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2008-08-22
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  295     ISSN:  0363-6135     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2008 Oct 
Date Detail:
Created Date:  2008-10-08     Completed Date:  2008-12-05     Revised Date:  2013-06-05    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H1720-5     Citation Subset:  IM    
Affiliation:
Heart and Vascular Institute, Pennsylvania State College of Medicine, Hershey, Pennsylvania 17033, USA. shayes1@hmc.psu.edu
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MeSH Terms
Descriptor/Qualifier:
Acid Sensing Ion Channels
Animals
Baroreflex* / drug effects
Blood Pressure
Capsaicin / administration & dosage
Cats
Decerebrate State
Female
Heart Rate
Hindlimb
Injections, Intra-Arterial
Isoquinolines / administration & dosage
Lactic Acid / metabolism*
Male
Muscle Contraction*
Muscle, Skeletal / innervation,  metabolism*
Naphthalenes / administration & dosage
Nerve Tissue Proteins / drug effects,  metabolism*
Neurons, Afferent / drug effects,  metabolism*
Physical Exertion*
Reflex, Stretch
Sodium Channels / drug effects,  metabolism*
Time Factors
Grant Support
ID/Acronym/Agency:
HL-30710/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/A-317567; 0/Acid Sensing Ion Channels; 0/Isoquinolines; 0/Naphthalenes; 0/Nerve Tissue Proteins; 0/Sodium Channels; 404-86-4/Capsaicin; 50-21-5/Lactic Acid
Comments/Corrections

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