Journals of Gerontology Series A: Biological Sciences and Medical Sciences Large Type Edition
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]
Author:
Keyword(s):
Year:  Vol:  Page: 


This Article
Full Text
Full Text (PDF)
Alert me when this article is cited
Alert me if a correction is posted
Services
Similar articles in this journal
Similar articles in PubMed
Alert me to new issues of the journal
Download to citation manager
Cited by other online articles
PubMed
PubMed Citation
Articles by Boluyt, M. O.
Articles by White, T. P.
The Journals of Gerontology Series A: Biological Sciences and Medical Sciences 55:B307-B314 (2000)
© 2000 The Gerontological Society of America

Age Effects on the Adaptive Response of the Female Rat Heart Following Aortic Constriction

Marvin O. Boluyta, Steven T. Devorb, Julie A. Opiteckc and Timothy P. Whited

a Division of Kinesiology, The University of Michigan, Ann Arbor.
b Section of Sport and Exercise Sciences, The Ohio State University, Columbus
c Department of Psychiatry, Duke University, Durham, North Carolina.
d College of Health and Human Performance, Oregon State University, Corvallis.

Correspondence: Marvin O. Boluyt, Laboratory of Molecular Kinesiology, The University of Michigan, 401 Washtenaw Avenue/1209 CCRB, Ann Arbor, MI 48109-2214 E-mail: [email protected].

Jay Roberts, PhD

Aging is associated with adaptations in the hearts of mammals that diminish the reserve capacity to meet hemodynamic loading challenges. To evaluate potential mechanisms of this phenomenon, the following hypotheses were tested: compared with hearts of adult rats, hearts of aged rats undergoing aortic constriction will exhibit (a) a lower concentration of myofibrillar proteins, (b) a reduced sensitivity to extracellular calcium, and (c) a reduced coronary perfusion. Female Fischer 344 rats aged 9 months (adult) and 27 months (aged) were assigned to control (C) or aortic-constriction (AC) groups and studied at 7 and 28 days post-AC, yielding six groups of rats. Analysis of variance was used to examine the effects of age and AC. The left ventricular (LV) mass/body mass ratio expressed a percentage of age-matched control value averaged AC-7adult, 111%; AC-28adult, 120%; AC-7aged, 106%; AC-28aged, 123% (AC, p < .01). As a percentage of adult rats values, the pressure-generating capacity of the LV averaged Caged, 99%; AC-7aged, 92%; AC-28aged, 92% (age, p < .05). There were no differences attributable to age or AC in either myofibrillar protein concentration or calcium sensitivity. There was, however, a significantly lower concentration of nonmyofibrillar protein (~10%) in the hearts of all three groups of aged rats compared with the adult rats that was unaltered by AC. The percentages of LV myosin heavy chain in the {alpha}-isoform were Cadult, 77%; AC-7adult, 66%; AC-28adult, 66%; Caged, 45%; AC-7aged, 41%; AC-28aged, 32% (age, p < .01; AC, p < .01). Coronary flow per gram of tissue averaged 9% lower in all three of the aged groups compared with the adult rats and was not significantly affected by AC (age, p < .05). The data suggest that a reduction in nonmyofibrillar protein and a reduced coronary flow, rather than changes in calcium sensitivity or myofibrillar protein, are associated with an impairment in the adaptive response of the aged heart.




This article has been cited by other articles:


Home page
Am. J. Physiol.Home page
P. Pacher, J. G. Mabley, L. Liaudet, O. V. Evgenov, A. Marton, G. Hasko, M. Kollai, and C. Szabo
Left ventricular pressure-volume relationship in a rat model of advanced aging-associated heart failure
Am J Physiol Heart Circ Physiol, November 1, 2004; 287(5): H2132 - H2137.
[Abstract] [Full Text] [PDF]




HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
All GSA journals The Gerontologist
Journals of Gerontology Series B: Psychological Sciences and Social Sciences
Copyright © 2000 by The Gerontological Society of America.