Document Detail

Transient depression of responses to sympathetic nerve stimulation overlying a subendocardial infarct.
MedLine Citation:
PMID:  8322927     Owner:  NLM     Status:  MEDLINE    
In previous work, the normal epicardial rim overlying a subendocardial infarct was demonstrated to be parasympathetically denervated. In the present study, we determined responses of effective refractory period (ERP) in this rim during sympathetic nerve stimulation (SNS). Eighteen dogs were studied 1-3 days after a 1-h or permanent coronary artery occlusion (group I). SNS shortened ERP in sites basal, septal, and lateral in the rim by 8 +/- 2, 7 +/- 2, and 7 +/- 2% (SE), respectively, which were similar to sites remote from the infarct (10 +/- 1%). These results were not altered by site of infarction or by atropine administration. To eliminate dissection of the coronary vessel and spontaneous ventricular tachycardia, 19 dogs were studied 6 h after a permanent bead embolization of a coronary artery (group II). In contrast to group I, ERP shortening in the rim sites of group II was depressed (3 +/- 3, 0 +/- 2, and 1 +/- 2%, respectively) compared with remote sites (10 +/- 1%, P < 0.05). In this group, collateral blood flow in the rim was no different than remote epicardium before and during SNS, and norepinephrine shortened ERP in the rim equivalent to remote sites. In an additional 31 animals (group III), the alteration in ATP-dependent K+ channel function was evaluated. Pretreatment with glyburide (an ATP-dependent K+ channel blocker) preserved ERP response to SNS (9 +/- 1% shortening of ERP vs. 12 +/- 2% at baseline) compared with only 3 +/- 0% shortening of ERP with vehicle (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
J B Martins; D G Cable; T E Rath; L Hingtgen; M Horn; D D Lund
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  264     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1993 Jun 
Date Detail:
Created Date:  1993-08-05     Completed Date:  1993-08-05     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  H1969-76     Citation Subset:  IM    
Department of Internal Medicine, University of Iowa, College of Medicine, Iowa City 52242.
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MeSH Terms
Atropine / pharmacology
Electric Stimulation
Endocardium / metabolism
Evoked Potentials / drug effects
Glyburide / pharmacology
Myocardial Infarction / metabolism,  physiopathology*
Potassium / metabolism
Refractory Period, Electrophysiological
Sympathetic Nervous System / drug effects,  physiopathology*
Time Factors
Grant Support
Reg. No./Substance:
10238-21-8/Glyburide; 51-55-8/Atropine; 7440-09-7/Potassium

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