title: Effect of aging on power output properties in rat skinned cardiac myocytes.
abstract: Aging is generally associated with a decline in several indices of cardiac function. The cellular mechanisms for this decline are not completely understood. The ability of the myocardium to perform external work (power output) is a critical aspect of ventricular function. The purpose of this study was to determine the effect of aging on loaded shortening and power output properties. We measured force-velocity properties in permeabilized (skinned) myocytes from the hearts of 9-, 24-, and 33-month-old male Fisher 344 × Brown Norway F1 hybrid rats (F344BN) during loaded contractions using a force-clamp technique. Power output was calculated by multiplying force and shortening velocity values. We found that peak power output normalized to maximal force was significantly decreased by 18% and 31% in myocytes from 24- and 33-month-old group, respectively, compared with 9-month group (p < .05). These results suggest that aging is associated with a significant decrease in the ability of the myocardium to do work.
authors: Balke, Biodynamics Laboratory, Department of Kinesiology, University of Wisconsin--Madison, Madison, WI 53706-1121, USA.
authors: Eunhee
authors: E
authors: Chung
authors: Gary M
authors: GM
authors: Diffee
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D001696:Biomechanical Phenomena; D008297:Male; D009200:Myocardial Contraction / Q000502:physiology*; D032383:Myocytes, Cardiac / Q000502:physiology*; D018995:Myosin Heavy Chains / Q000378:metabolism; D051381:Rats; D011914:Rats, Inbred BN; D011916:Rats, Inbred F344
chemical_list: D018995:Myosin Heavy Chains