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Intramuscular calcium movements: experiments from the Soviet biosatellite Biocosmos
1Laboratoire de Physiologie des Structures Contractiles, Universite des Sciences et Techniques de Lille I, France.
Advances in Space Research : the Official Journal of the Committee on Space Research (COSPAR)
|January 1, 1984
Summary
Microgravity exposure reduces maximal muscle strength and impairs calcium handling in rat skeletal muscle fibers. This affects both calcium release and uptake by the sarcoplasmic reticulum, impacting muscle function.
Area of Science:
- Muscle physiology
- Space biology
- Calcium signaling
Background:
- Skeletal muscle adapts to altered loading conditions.
- Microgravity is known to induce muscle atrophy and functional decline.
- Intramuscular calcium (Ca) regulation is critical for muscle contraction.
Purpose of the Study:
- To investigate the effects of microgravity on skeletal muscle contractile properties.
- To assess changes in intracellular calcium movements in response to microgravity.
- To understand the impact of spaceflight on the sarcoplasmic reticulum's Ca handling.
Main Methods:
- Experiments utilized chemically skinned muscle fibers from the rat gastrocnemius muscle.
- Measurements of muscle tension were performed to assess contractile strength.
- Analysis focused on calcium release and uptake kinetics by the sarcoplasmic reticulum.
Main Results:
- Microgravity exposure led to a significant decrease in maximal muscle strength.
- The intensity and rate of both Ca release from and Ca uptake into the sarcoplasmic reticulum were reduced.
- Contractile proteins showed diminished force development.
Conclusions:
- Microgravity adversely affects skeletal muscle contractile function.
- Impaired calcium handling by the sarcoplasmic reticulum is a key mechanism underlying microgravity-induced muscle weakness.
- These findings highlight the need for countermeasures against spaceflight-induced muscle deconditioning.