Difference in activation by Tris(hydroxymethyl)aminomethane of Ca,Mg-ATPase activity between young and old rat...

Area of Science:

• Gerontology
• Skeletal Muscle Physiology
• Biochemistry

Background:

• Skeletal muscle mass and function decline with aging.
• Age-related changes in muscle enzyme activity, specifically ATPases, are not fully understood.
• Myosin-ATPase and Ca,Mg-ATPase are key enzymes in muscle contraction and calcium handling.

Purpose of the Study:

• To investigate age-related changes in the fresh weight of rat skeletal muscles.
• To determine the specific activity of myosin-ATPase and Ca,Mg-ATPase in aging rat skeletal muscles.
• To examine the effect of Tris(hydroxymethyl)aminomethane concentration on Ca,Mg-ATPase activity in different age groups.

Main Methods:

• Measurement of fresh weight of M. tibialis anterior in rats of varying ages.
• Assay of specific activity for myosin-ATPase and Ca,Mg-ATPase in muscle homogenates.
• Analysis of Ca,Mg-ATPase activation by high concentrations of Tris(hydroxymethyl)aminomethane.

Main Results:

• Rat skeletal muscle fresh weight significantly decreased with age.
• Specific activity of myosin-ATPase decreased significantly in older rats.
• Ca,Mg-ATPase activity remained unchanged with age, but its activation by high Tris concentrations was reduced in older rats compared to younger rats.

Conclusions:

• Aging leads to a reduction in skeletal muscle mass and myosin-ATPase activity.
• While Ca,Mg-ATPase itself is not diminished, its functional response to buffer conditions is impaired in aged rats.
• These findings suggest an age-related alteration in the regulatory mechanisms of Ca,Mg-ATPase in skeletal muscle.