Effect of physical training on myocardial enzyme activities in aging rats

Chesky, Jeffrey A.; LaFollette, Suzanne; Travis, M.; Fortado, C.

doi:10.1152/jappl.1983.55.4.1349

Cited by 21 publications

(6 citation statements)

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“…The above observations supported the concept put forward by Edington and coworkers that for a certain intensity and duration of exercise there is a threshold of age beyond which exercise may be deleterious to the aging animals (74). Similar observations of a threshold of age prevailing for myocardial ATPase and creatine kinase activities were reported by Chesky et al (75). More recent studies by Holloszy and Smith have shown that rats exercised regularly from very young age indeed have had a longer mean life span than their counterpart sedentary controls (76).…”

Section: The Influence Of External Conditions and Environmental Factorssupporting

confidence: 89%

The Physiology and Biochemistry of Skeletal Muscle Atrophy as a Function of Age

Carmeli¹,

Reznick²

1994

Experimental Biology and Medicine

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The skeletal muscles are an important entity in the proper function of aging animals and humans. Studies have shown that until humans are 60-70 years old, age-related changes in muscle function and structure are relatively small, while after 70 years, these alterations are accelerated considerably. Factors responsible for the "aging" of skeletal muscles are complex and include intrinsic biochemical changes in muscle metabolism, changes in the distribution and size of muscle fibers, and a general loss of muscle mass. In addition, other factors like the control of muscle contraction by the motor neural system and the influence of external conditions such as exercise, immobility, nutrition and others may also contribute to the age-related decrease in muscle functions. Studies have shown that with age there is some loss of peripheral motor neurons, reduction in the number of motor units, alterations in the neuromuscular junctions, and selective denervation of Type II muscle fibers. These findings led to the concept of denervation atrophy of skeletal muscles as one of the major mechanisms for muscle degeneration in old age. However, it should be emphasized that the extent of age-related changes varies from muscle to muscle, and some do not seem to be affected by age. For example, it has been shown recently, in animal studies, that weight-bearing muscles are much more susceptible to senescent processes than non-weight-bearing muscles. More work is needed to clarify the contributions of the various factors, especially the role of muscle training in alleviating the symptoms of age-related muscle atrophy.

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Section: The Influence Of External Conditions and Environmental Factorssupporting

confidence: 89%

The Physiology and Biochemistry of Skeletal Muscle Atrophy as a Function of Age

Carmeli¹,

Reznick²

1994

Experimental Biology and Medicine

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“…The present and previous data [2,3,5,[7][8][9][12][13][14] lead us to conclude that the capacity to adapt to physical exercise in skeletal muscle, heart muscle and bone tis sue is probably maintained as long as the training program has started prior to a cer tain threshold of age, which is at least 15 months in mice (e.g. the result depicted in figure 4).…”

Section: Discussionsupporting

confidence: 69%

Effect of Short- and Long-Term Endurance Training on Creatine Phosphokinase Activity in Skeletal and Cardiac Muscles of CW-1 and C57BL Mice

Steinhagen‐Thiessen

Reznick

1987

Gerontology

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Creatine phosphokinase (CPK) has been shown to provide the initial ATP for muscle contraction. The effect of wheel running on CPK levels was compared in hindleg and cardiac muscles of young, intermediate-age and old outbred CW-1 and inbred C57BL mice. Short-term (5 weeks) and long-term (over 12 months) regimens were used in these studies. It was shown that as a function of age there was a 20–30% decrease of CPK activity in hindleg muscles of old sedentary animals. No change with age was observed in cardiac muscles of old animals. Short-term exercise of 5 weeks resulted in an increase in CPK levels in young running mice in both hindleg and cardiac muscles. In old animals there was a slight decrease in striated hindleg muscles, but no change in cardiac muscles. In the long-term exercise group, young (6-month-old) and intermediate-age (15-month-old) animals showed a 20–40 % increase in CPK specific activity in hindleg muscles over sedentary control mice. No such increase in CPK activity was observed in old trained mice. However, the long-term exercise regimen prevented the age-associated decline in CPK activity found in sedentary animals.

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“…As the euthyroid rat matures, the percent of V, decreases while the percent of V 3 increases, l8 - 25 - 28 and this shift is accompanied by a decrease in the ATPase acby guest on May 10, 2018 http://circres.ahajournals.org/ Downloaded from tivities in a variety of myofilament preparations. 29 " 31 With further adult aging into senescence, the ATPase activity in some but not all myofilament preparations continues to decline 2930 - 32 and the contraction duration becomes prolonged.…”

mentioning

confidence: 99%

Changes in myosin isoenzymes, ATPase activity, and contraction duration in rat cardiac muscle with aging can be modulated by thyroxine.

Effron¹,

Bhatnagar²,

Spurgeon³

et al. 1987

Circulation Research

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To determine whether the relative decline in cardiac myosin isoenzyme V, with maturation continues progressively into senescence and whether thyroxine could reverse age-associated changes in the myosin isoenzyme profile and contraction, rats 2, 8, and 24 months old were treated with thyroxine, 6.4 mg/kg, for 7 days. Myosin isoenzymes, Ca 2+ -myosin ATPase activities, and isometric contractile function were measured in cardiac preparations from thyroxine-treated animals and age-matched controls. Right ventricular hypertrophy did not occur with aging in controls. Thyroxine increased right ventricular weight in each age group compared to the control group. Body weight decreased by 10% in all thyroxine-treated rats. The relative right ventricular V, isoenzyme content progressively decreased from 75 ± 1% to 54 ± 1% and 14 ± 1% in controls at 2,8, and 24 months, respectively, and was associated with a reciprocal increase in V 3 myosin isoenzyme. Ca 2+-myosin ATPase activity also progressively declined monotonically with age in the control rats from 854 ± 28 nmol Pi/mg prot/min at 2 months to 529 ± 28 nmol Pi/mg prot/min at 24 months. Thyroxine administration increased right ventricular V, at each age to 97 ± 2%, 73 ± 2%, and 59 ± 2% at 2, 8, and 24 months, respectively. A thyroxine induced increase in the Ca 1+ -myosin ATPase activity could be detected only in the 24-month-old animals. Isometric contraction duration in thin right ventricular papillary muscles increased with age from 172 ± 4 to 180 ± 5 to 225 ± 8 ms at 2, 8, and 24 months, respectively, and was markedly shortened (p<0.001) by thyroxine at each age so that the 24-month thyroxine value was less than the 2-month control. The maximum rate of force production did not change with age in controls and was increased by thyroxine at all ages. Thus, with aging from maturation to senescence, even in the absence of right ventricular hypertrophy, there is a profound monotonic decrease in percent right ventricular V, that is paralleled by a decline in Ca As the euthyroid rat matures, the percent of V, decreases while the percent of V 3 increases, l8 -25 -28 and this shift is accompanied by a decrease in the ATPase ac-

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Effect of physical training on myocardial enzyme activities in aging rats

Cited by 21 publications

References 0 publications

The Physiology and Biochemistry of Skeletal Muscle Atrophy as a Function of Age

The Physiology and Biochemistry of Skeletal Muscle Atrophy as a Function of Age

Effect of Short- and Long-Term Endurance Training on Creatine Phosphokinase Activity in Skeletal and Cardiac Muscles of CW-1 and C57BL Mice

Changes in myosin isoenzymes, ATPase activity, and contraction duration in rat cardiac muscle with aging can be modulated by thyroxine.

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