Document Detail


Time-course effects of sinoaortic denervation on contractile state of the rat myocardium.
MedLine Citation:
PMID:  1653536     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Sinoaortic baroreceptor denervation (SAD) in the rat immediately produces hypertension and tachycardia, as the result of an increased sympathetic tone to the heart and resistance vessels. Adaptive processes are then installed, changing according to the duration of the SAD. In this work we studied the time course of adaptive changes occurring in the rat heart within a 30-day period. Heart rate and mean blood pressure were measured before mechanical studies in the isometrically contracting left ventricle papillary muscles. Results showed that heart rate and mean blood pressure increased immediately after the SAD. Heart rate normalized 15 days later, although hypertension persisted. Thirty days later both rate and pressure normalized. Mechanical studies showed that isometric force development (F) and its first-time derivative (dF/dt) behaved similar to controls until the 1st wk but displayed a contractile depression in the 2nd wk after SAD. However, after 30 days this depression subsided and both F and dF/dt were back to normal values. The beta-adrenoceptor responsiveness also changed during this 30-day period. Three days after denervation there was an increased sensitivity to isoproterenol action in the muscles. This sensitivity was progressively reduced as the time after denervation increased. The absence of a similar behavior with the rest-potentiated contractions suggests that these time-course adaptive changes are specific for beta-adrenoceptor stimulation.
Authors:
D V Vassallo; E C Vasquez; J G Mill; A M Cabral
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The American journal of physiology     Volume:  261     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1991 Sep 
Date Detail:
Created Date:  1991-10-04     Completed Date:  1991-10-04     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  H639-43     Citation Subset:  IM    
Affiliation:
Departamento de Ciências Fisiológicas, Centro Biomédico, UFES, Victoria, ES, Brazil.
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MeSH Terms
Descriptor/Qualifier:
Animals
Blood Pressure*
Denervation*
Heart Rate*
Isometric Contraction
Isoproterenol / pharmacology
Male
Myocardial Contraction* / drug effects
Papillary Muscles / drug effects,  physiology*
Pressoreceptors / physiology
Rats
Rats, Inbred Strains
Receptors, Adrenergic, beta / drug effects,  physiology
Sinoatrial Node / physiology*
Time Factors
Chemical
Reg. No./Substance:
0/Receptors, Adrenergic, beta; 7683-59-2/Isoproterenol

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


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