Document Detail

Effect of chronic nifedipine treatment on blood pressure and adrenergic responses of isolated mesenteric artery in young rats with developing spontaneous hypertension.
MedLine Citation:
PMID:  20059291     Owner:  NLM     Status:  MEDLINE    
It is documented that in chronic hypertensive state there is an increased vasodepressor response to calcium channel antagonists such as the dihydropyridine derivate nifedipine. This effect is generally proportional to initial blood pressure as was demonstrated in several models of experimental hypertension. In the present study we investigated the effect of chronic nifedipine treatment on the development of cardiovascular system in young spontaneously hypertensive rats (SHR) in order to evaluate whether it could prevent the abnormalities leading to hypertensive state. Four- and eight-week-old rats were treated with nifedipine (50 mg/kg/day) for 4 weeks. Blood pressure of nifedipine-treated SHR remained at the initial level in contrast to their untreated controls where it continued to increase. In both age groups, chronic nifedipine administration reduced neurogenic contractions of isolated superior mesenteric artery, but did not significantly affect the dose-response curve to exogenous noradrenaline in 8-week-old rats. In contrast, maximum response to noradrenaline was significantly attenuated in mesenteric artery of 12-week-old nifedipine-treated SHR. We can presume that the antihypertensive effect of nifedipine is similar in both stages of spontaneous hypertension development, but the mechanisms involved might be different. It seems that chronic reduction of calcium influx during the rapid phase of pathological blood pressure increase in SHR may eliminate the effect of enhanced sympathetic tone, which may have unfavorable consequences on cardiovascular structure and function.
A Zemanc?kov?; J T?r?k
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Physiological research / Academia Scientiarum Bohemoslovaca     Volume:  58     ISSN:  0862-8408     ISO Abbreviation:  Physiol Res     Publication Date:  2009  
Date Detail:
Created Date:  2010-01-11     Completed Date:  2010-02-23     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9112413     Medline TA:  Physiol Res     Country:  Czech Republic    
Other Details:
Languages:  eng     Pagination:  921-5     Citation Subset:  IM    
Institute of Normal and Pathological Physiology, Slovak Academy of Sciences, Bratislava, Slovak Republic.
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MeSH Terms
Age Factors
Antihypertensive Agents / pharmacology*
Blood Pressure / drug effects*
Calcium / metabolism
Calcium Channel Blockers / pharmacology*
Disease Models, Animal
Disease Progression
Dose-Response Relationship, Drug
Electric Stimulation
Hypertension / drug therapy*,  metabolism,  physiopathology
Mesenteric Arteries / drug effects*,  metabolism,  physiopathology
Nifedipine / pharmacology*
Norepinephrine / pharmacology*
Rats, Inbred SHR
Rats, Wistar
Sympathetic Nervous System / drug effects,  physiopathology
Vasoconstriction / drug effects*
Vasoconstrictor Agents / pharmacology*
Reg. No./Substance:
0/Antihypertensive Agents; 0/Calcium Channel Blockers; 0/Vasoconstrictor Agents; 21829-25-4/Nifedipine; 51-41-2/Norepinephrine; 7440-70-2/Calcium

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

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