scholarly journals Studies on the adenosine triphosphatase, calcium uptake and relaxing activity of the microsomal granules from skeletal muscle.

1965 ◽  
Vol 179 (3) ◽  
pp. 456-478 ◽  
Author(s):  
K S Lee ◽  
K Tanaka ◽  
D H Yu
Keyword(s):  
Skeletal Muscle ◽  
Adenosine Triphosphatase ◽  
Calcium Uptake

Defective Membrane Systems in Dystrophic Skeletal Muscle of the UM-X7.1 Strain of Genetically Myopathic Hamster

1975 ◽  
Vol 49 (4) ◽  
pp. 359-368
Author(s):  
N. S. Dhalla ◽  
A. Singh ◽  
S. L. Lee ◽  
M. B. Anand ◽  
A. M. Bernatsky ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Atpase Activity ◽  
Calcium Binding ◽  
Adenosine Triphosphatase ◽  
Calcium Uptake ◽  
Initial Rate ◽  
The Other ◽  
Membrane Systems ◽  
Dystrophic Muscle ◽  
Mitochondrial Calcium Uptake

1. The function of mitochondria, sarcotubular membranes (heavy microsomes), sarcolemma and myofibrils from the hind-leg skeletal muscle of about 60- and 150-day-old normal and myopathic (UM-X7.1) hamsters was examined. 2. The mitochondrial calcium uptake as well as mitochondrial phosphorylation and respiratory rates were lower in 60-day-old myopathic skeletal muscle, unlike 150-day-old myopathic animals, when pyruvate-malate and glutamate-malate were used as substrates. However, mitochondria from 150-day-old myopathic animals showed depressed glutamate-dependent respiratory and phosphorylation rates and succinate-supported initial rate of calcium uptake. 3. The microsomal calcium-uptake, but not calcium-binding, and Ca2+-stimulated adenosine triphosphatase (ATPase) activity of the 150-day-old myopathic skeletal muscle were lower than the control values. Although microsomal calcium-binding, calcium-uptake and ATPase activities of the 60-day-old myopathic muscle were not depressed significantly, the initial rate of calcium uptake was less than the control. 4. The sarcolemmal Ca2+-ATPase, but not Mg2+-ATPase or Na+ +K+-ATPase, activity was higher in 60-day-old myopathic muscle whereas the activities of all these enzymes from 150-day-old myopathic animals were higher than the control. On the other hand, the Na+ +K+-ATPase activities from 60- and 150-day-old myopathic animals were inhibited by ouabain to a lesser extent in comparison with the respective control values. 5. The myofibrillar Ca2+-ATPase and Mg2+-ATPase activities as well as inhibition of Mg2+-ATPase due to Na+ and K+ in myopathic muscle were no different from the control values. 6. The results reported here give further support to the view that different membrane systems of the dystrophic muscle are defective.

Nitrendipine blocks high potassium contractures but not twitches in rat skeletal muscle

1988 ◽  
Vol 66 (9) ◽  
pp. 1210-1213 ◽  
Author(s):  
G. B. Frank ◽  
L. Konya ◽  
T. Subrahmanyam Sudha
Keyword(s):  
Skeletal Muscle ◽  
Calcium Ions ◽  
Calcium Uptake ◽  
Channel Blocker ◽  
Mechanical Response ◽  
Extracellular Calcium ◽  
The Other ◽  
Rat Skeletal Muscle ◽  
Potassium Depolarization ◽  
High Potassium

The effects of the organic calcium channel blocker nitrendipine was tested on electrically evoked twitches and on potassium depolarization-induced contractures of rat lumbricalis muscles. Nitrendipine (10−7 to 5 × 10−5 M) blocked only the potassium contractures. It was concluded that blocking calcium uptake through the slow voltage-senstitive calcium channels during potassium depolarization blocks the mechanical response of the muscle. Thus extracellular calcium ions are required for the excitation–contraction (E–C) coupling during depolarization contractures. On the other hand, electrically evoked twitches were not affected by nitrendipine; therefore, extracellular calcium ions entering via the slow voltage-sensitive channels are not required for E–C coupling during the twitch.

Intracellular distribution of succinate dehydrogenase activity in skeletal muscle fibers of geese

1984 ◽  
Vol 62 (2) ◽  
pp. 235-240 ◽  
Author(s):  
H. J. Swatland
Keyword(s):  
Skeletal Muscle ◽  
Succinate Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Adenosine Triphosphatase ◽  
Muscle Fibers ◽  
Fiber Types ◽  
Succinate Dehydrogenase Activity ◽  
Individual Muscle ◽  
Concentric Zone ◽  
Pectoralis Muscles

Samples of iliotibialis anterior and pectoralis muscles were taken from five ganders (Anser domesticus). Serial transverse sections were reacted for succinate dehydrogenase (SDH) and alkali-stable adenosine triphosphatase (ATPase). The distribution of SDH activity within individual muscle fibers was measured with a scanning photometer. In many individual fibers, SDH activity was stronger in the periphery than in the axis. This gradient was steepest (−0.034 ± 0.019 absorbance units per concentric zone of 2 μm diameter measurements) in pectoralis fibers with strong SDH activity. In the pectoralis, radial gradients were correlated with fiber area so that the smallest fibers tended to have the steepest gradients of SDH activity. However, this relationship was reversed in fibers with strong ATPase and weak SDH activity in the iliotibialis anterior, and the largest fibers tended to have the steepest gradients. In all fiber types of both muscles, fibers with greater mean SDH activity tended to have steeper gradients.

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