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Summary
Disuse atrophy in skeletal muscle leads to resistance to pancuronium, a neuromuscular blocking agent. Immobilized muscles require higher doses of this drug for effective paralysis.
Area of Science:
- Anesthesiology
- Pharmacology
- Neuromuscular Physiology
Background:
- Disuse atrophy is a common condition in immobilized patients.
- The effect of disuse atrophy on neuromuscular blockade is not well understood.
Purpose of the Study:
- To investigate the impact of disuse atrophy on skeletal muscle response to pancuronium.
Main Methods:
- Dose-response curves for pancuronium were determined in immobilized (casted) and non-immobilized (uncasted) gastrocnemius muscles of dogs.
- Muscle responses were measured using train-of-four nerve stimulation under anesthesia.
Main Results:
- The immobilized (casted) gastrocnemius muscle showed resistance to pancuronium.
- The ED50 for pancuronium was significantly higher in the atrophied muscle (0.051 mg/kg) compared to the normal muscle (0.027 mg/kg), with a potency ratio of 1.89.
Conclusions:
- Skeletal muscle disuse atrophy results in resistance to pancuronium.
- Immobilized patients may require increased doses of non-depolarizing neuromuscular blocking agents for adequate paralysis.