Document Detail

Potassium relaxation of vascular smooth muscle from DOCA hypertensive pigs.
MedLine Citation:
PMID:  6286478     Owner:  NLM     Status:  MEDLINE    
This study was designed to characterize potassium-induced relaxation in vascular smooth muscle during the development of deoxycorticosterone acetate (DOCA) hypertension. Pigs were implanted subcutaneously with 100 mg/kg DOCA. Mean arterial pressure in the DOCA-treated pigs reached levels approximately 37% greater than controls. In some pigs, the left hindlimb vascular bed was "protected" from the rise in arterial pressure by ligation of the iliac artery. Arterial strips from DOCA hypertensive and normotensive pigs relaxed in response to potassium after contraction induced by norepinephrine in potassium-free solution. Arterial strips from DOCA hypertensive pigs showed greater relaxation than did those from normotensive pigs. The magnitude of relaxation in femoral arteries from "protected" hindlimbs was similar to that in arteries from the contralateral unoccluded limb. Potassium-induced relaxation in tail arteries from DOCA hypertensive pigs was more sensitive to ouabain inhibition than that from normotensive pigs. Relaxation induced by potassium varied with: 1) length of incubation in potassium-free solution; 2) concentration of added potassium; and 3) concentration of norepinephrine added during the potassium-free interval. The amplitude of potassium-induced relaxation is believed to be a functional index of the activity of the electrogenic sodium-potassium transport system. These experiments support the hypothesis that vascular smooth muscle from DOCA hypertensive animals has increased electrogenic sodium pump activity. The development of this vascular change parallels the increase in blood pressure induced by mineralocorticoid excess.
R C Webb
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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:  Hypertension     Volume:  4     ISSN:  0194-911X     ISO Abbreviation:  Hypertension     Publication Date:    1982 Sep-Oct
Date Detail:
Created Date:  1982-10-29     Completed Date:  1982-10-29     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  7906255     Medline TA:  Hypertension     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  609-19     Citation Subset:  IM    
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MeSH Terms
Arteries / drug effects
Blood Pressure
Hypertension / chemically induced*,  physiopathology
Ion Channels / metabolism
Muscle Contraction / drug effects*
Muscle Relaxation / drug effects*
Muscle, Smooth, Vascular / drug effects*
Norepinephrine / pharmacology
Ouabain / pharmacology
Potassium / pharmacology*
Sodium / metabolism
Time Factors
Grant Support
Reg. No./Substance:
0/Ion Channels; 51-41-2/Norepinephrine; 630-60-4/Ouabain; 64-85-7/Desoxycorticosterone; 7440-09-7/Potassium; 7440-23-5/Sodium

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