Calcium transport by sarcoplasmic reticulum of skeletal muscle is inhibited by antibodies against the 53-kilodalton glycoprotein of the sarcoplasmic reticulum membrane

Biochemistry ◽  
1989 ◽  
Vol 28 (11) ◽  
pp. 4830-4839 ◽  
Author(s):  
Howard Kutchai ◽  
Kevin P. Campbell
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Calcium Transport ◽  
Sarcoplasmic Reticulum Membrane

The Modulation of the Calcium Transport by Skeletal Muscle Sarcoplasmic Reticulum in the Hibernating European Hamster

1991 ◽  
Vol 46 (11-12) ◽  
pp. 1109-1126 ◽  
Author(s):  
◽  
Luisa De Martino ◽  
Barbara Soltau ◽  
Wilhelm Hasselbach
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Calcium Transport ◽  
Calcium Uptake ◽  
Calcium Release ◽  
Ion Homeostasis ◽  
Free Calcium ◽  
Type I ◽  
Calcium Dependent ◽  
Calcium Affinity

Calcium transport of skeletal muscle sarcoplasmic reticulum was comparatively studied in hibernating and summer active European hamsters (Cricetus cricetus L.). Crude homogenates from psoas, soleus and mixed skeletal muscles were used. Protein yield was strongly reduced in the muscle homogenates of hibernating hamsters. The calcium concentration in the muscle of hibernating hamsters was increased to a much higher content than in the serum. In the same animals the maximal rate of calcium uptake and the calcium storing capacity of sarcoplasmic reticulum were augmented by 43% and respectively 17%. Kinetic experiments with various concentrations of free calcium revealed in the hibernating animals higher uptake rates and a lower apparent calcium affinity than in the summer active hamsters. Some shift of calcium uptake rate and calcium affinity similar to that of a fast-twitch muscle was also observed in winter active animals kept at 22 C under natural photoperiod. By contrast, the activity of the calcium dependent ATPase was not increased, suggesting a tighter coupling during hibernation between calcium dependent ATP-hydrolysis and calcium transport. No seasonal difference was observed in the calcium release by KCl-caffeine from calcium loaded vesicles of sarcoplasmic reticulum.Proportion and size of fibre types were studied with cold cross sections from psoas and soleus muscles. An average atrophy of about 25% was found during hibernation in both muscles. Cytochemistry revealed, however, a different reduction of cross area between type-I- and type-11-fibres, which reaches values up to 46% in the type-I I-fast-fibres of the slow soleus muscle. Electron microscopy did not show any definite change in the distribution and amount of sarcoplasmic reticulum.The results suggest that during hibernation a modulation in the properties of calcium transport ATPase of sarcoplasmic reticulum occurs to better support the calcium transport function at low temperatures, which in turn warrants the restoration of ion homeostasis in the course of the arousal.

On the Problem of Season and Cold Dependence of Calcium Transport by Skeletal Muscle Sarcoplasmic Reticulum

1990 ◽  
Vol 45 (6) ◽  
pp. 671-675 ◽  
Author(s):  
Bruno Agostini ◽  
Luisa De Martino ◽  
Wilhelm Hasselbach
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Cold Acclimation ◽  
Uptake Rate ◽  
Calcium Transport ◽  
Calcium Uptake ◽  
Kinetic Studies ◽  
Cold Season ◽  
Free Calcium ◽  
Calcium Affinity

Abstract Calcium transport of skeletal muscle sarcoplasmic reticulum from golden hamsters was studied in January and in June on animals kept at 22 °C under natural photoperiod and in January after cold-acclimation at ±2 °C in the dark for 55 days. Crude homogenates from psoas and soleus muscles and from mixed skeletal muscles were used. No differences were observed in the calcium storing capacity of sarcoplasmic reticulum among the three groups of animals. Kinetic studies on the dependence of the calcium uptake rate on the concentration of free calcium revealed a significant increase of the uptake rates and a decrease of the calcium affinity in the control animals sacrificed in winter as compared to those killed in June. Cold-acclimation in winter leads to a further small reduction of the calcium affinity. This shift of calcium uptake rate and affinity in the sense of that of a fast-twitch muscle may be related to the functional demands of the cold season and cold-acclimation respectively.

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