Neuronal control of bone and muscle

• Bone homeostasis is regulated by powerful neural pathways that emanate from the hypothalamus.
• The major efferent neural effector pathway to bone is the sympathetic nervous system (SNS).
• Muscle is also regulated by the SNS, but in opposition to bone: The SNS is anabolic in muscle, but is anti-anabolic in cancellous bone.
• The ob/ob mouse is a well characterised model wherein reduced sympathetic tone increases cancellous bone mass, but reduces muscle mass.
• This indicates the existence of co-ordinated regulation of bone and muscle mass through central pathways

The functional interplay between bone and muscle that enables locomotion is a fundamental aspect of daily life. However, other interactions between bone and muscle continue to attract attention as our understanding of the breath and importance of this inter-relationship continues to expand. Of particular interest is the regulatory connection between bone and muscle, which adds a new insight to the coordination of the bone/muscle unit. We have appreciated the importance of neuronal signaling to the control of bone turnover and muscle contraction, but recent data indicate that neuronal inputs control a far wider range of bone and muscle physiology than previously appreciated. This review outlines the role of the sympathetic nervous system and neuronal/neuropeptide inputs upon the regulation of bone and muscle tissue, and the potential for co-regulatory actions, particularly involving the sympathetic nervous system.This article is part of a Special Issue entitled “Muscle Bone Interactions”.