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Increased muscle calcium. A possible cause of mitochondrial dysfunction and cellular necrosis in denervated rat
Abstract:
Mitochondrial preparations derived from denervated rat skeletal muscle and paired controls were characterized with respect to their ability to take up externally added Ca2+. The denervated and control muscle homogenates and mitochondrial [Ca2+] were also determined. Our data indicate that the denervated mitochondria are able to take up less Ca2+ than the controls before uncoupling occurs. This defect is associated with elevated [Ca2+] in homogenate and mitochondrial fractions in the denervated state. The causal relationship between Ca2+ overload, mitochondrial functional damage and cell necrosis is discussed.
Insights
Denervated rat muscle mitochondria show impaired calcium uptake, leading to overload and potential cell damage. This highlights mitochondrial dysfunction in muscle atrophy.
Area of Science:
- Mitochondrial biochemistry
- Skeletal muscle physiology
- Cellular pathology
Background:
- Mitochondria play a crucial role in cellular calcium homeostasis.
- Muscle denervation leads to significant physiological and biochemical changes.
Purpose of the Study:
- To investigate the effect of muscle denervation on mitochondrial calcium uptake in rats.
- To determine the relationship between impaired calcium handling, mitochondrial function, and cell necrosis in denervated muscle.
Main Methods:
- Mitochondrial preparations from denervated and control rat skeletal muscle were isolated.
- Calcium uptake capacity of mitochondria was measured.
- Calcium concentrations in homogenate and mitochondrial fractions were determined.
Main Results:
- Denervated mitochondria exhibited reduced capacity for calcium uptake compared to controls.
- Elevated calcium levels were observed in both homogenate and mitochondrial fractions of denervated muscle.
- Impaired calcium uptake preceded mitochondrial uncoupling.
Conclusions:
- Muscle denervation causes mitochondrial dysfunction characterized by defective calcium handling.
- Calcium overload in denervated mitochondria may contribute to mitochondrial damage and subsequent cell necrosis.
- These findings suggest a potential mechanism for cell death in denervated skeletal muscle.