2022 Volume 59 Issue 3 Pages 278-283
The age-related decline in muscle mass and strength (sarcopenia) may involve the role of the autonomic nervous system in skeletal muscle function in addition to the muscle and motor nervous systems. Muscle sympathetic nerves, which are considered to be adrenergic vasoconstrictors, are histologically distributed in muscle fibers and neuromuscular endplates, and may be involved in the maintenance of skeletal muscle mass and the regulation of contractility. We found that the triceps muscle tetanic force induced by tibial nerve stimulation was attenuated by cutting the lumbar sympathetic trunk, lumbar dorsal roots, or cervical spinal cord, and that reflex potentials were evoked in the lumbar sympathetic postganglionic fibers in response to muscle contraction, indicating that reflex excitation of sympathetic nerves by skeletal muscle contraction contributes to the maintenance of contractility of that muscle. The possibility that this mechanism diminishes with aging and may contribute to sarcopenia is discussed.
