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Titolo:
Exercise training increases the Ca2+ sensitivity of tension in rat cardiacmyocytes
Autore:
Diffee, GM; Seversen, EA; Titus, MM;
Indirizzi:
Univ Wisconsin, Dept Kinesiol, Biodynam Lab, Madison, WI 53706 USA Univ Wisconsin Madison WI USA 53706 , Biodynam Lab, Madison, WI 53706 USA
Titolo Testata:
JOURNAL OF APPLIED PHYSIOLOGY
fascicolo: 1, volume: 91, anno: 2001,
pagine: 309 - 315
SICI:
8750-7587(200107)91:1<309:ETITCS>2.0.ZU;2-C
Fonte:
ISI
Lingua:
ENG
Soggetto:
LIGHT-CHAIN PHOSPHORYLATION; SINGLE VENTRICULAR MYOCYTES; SKELETAL-MUSCLE FIBERS; ENDURANCE EXERCISE; SARCOPLASMIC-RETICULUM; SHORTENING VELOCITY; ATPASE ACTIVITY; C-PROTEIN; MYOSIN; HEART;
Keywords:
myocardium; tension-pCa; endurance training; contractility;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
39
Recensione:
Indirizzi per estratti:
Indirizzo: Diffee, GM Univ Wisconsin, Dept Kinesiol, Biodynam Lab, 2000 Observ Dr, Madison, WI 53706 USA Univ Wisconsin 2000 Observ Dr Madison WI USA 53706 WI 53706 USA
Citazione:
G.M. Diffee et al., "Exercise training increases the Ca2+ sensitivity of tension in rat cardiacmyocytes", J APP PHYSL, 91(1), 2001, pp. 309-315

Abstract

The heart is known to respond to a program of chronic exercise in ways that enhance cardiac function. However, the cellular mechanisms involved in training-induced improvements in the contractile function of the myocardium are not known. In this study we tested the hypothesis that increased contractility of the myocardium associated with exercise training is due, in part,to increases in the Ca2+ sensitivity of steady-state tension. Female Sprague-Dawley rats were randomly divided into sedentary control (C) and exercise-trained (T) groups. The T rats underwent 11 wk of progressive treadmill exercise (1 h/day, 5 days/wk, 26 m/min, 20% grade). Evidence of training effect included a 5.9% increase in heart mass, increases in heart weight-to-body weight ratio, and a 60% increase in skeletal muscle citrate synthase activity in T rats compared with C rats. After the training program, cardiac myocytes were isolated from T and C hearts. Myocytes were chemically skinned(i.e., the sarcolemma was removed) and attached to a force transducer, andsteady-state tension was determined in solutions of various Ca2+ concentrations ([Ca2+]). Myocytes isolated from the hearts of T rats showed a significantly (P < 0.01) increased sensitivity of tension to [Ca2+]. The [Ca2+] giving 50% of maximal tension (pCa(50)) was 5.90 +/- 0.033 and 5.82 +/- 0.023 (SD) in T and C myocytes, respectively (n = 70 myocytes/group). This result suggests that exercise training affects the myofibrillar proteins, such that Ca2+ sensitivity is increased, and that this may be the mechanism thatunderlies, at least in part, the effect of training to increase myocardialcontractility.

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Documento generato il 20/01/20 alle ore 22:28:05