The fields of neuroscience and bone biology have recently converged following the discovery that bone remodeling is directly
regulated by the brain. This work has defined bone remodeling as one of the cardinal physiological functions of the body,
subject to homeostatic regulation and integrated with the other major physiological functions by the hypothalamus. Central
to this discovery was the definition of the adipocyte-derived hormone leptin as a regulator of both arms of bone remodeling,
formation and resorption, through its action on the ventromedial hypothalamus and subsequently via the sympathetic nervous
system to osteoblasts. The characterization of the sympathetic nervous system as a regulator of bone remodeling has led to
several large clinical studies demonstrating a substantial protective effect of ß-blockers, particularly ß1-blockers, on fracture
risk. Studies in model organisms have reinforced the role of the central nervous system in the regulation of bone remodeling
in vivo by the identification of several additional genes, namely cocaine and amphetamine regulated transcript (
Cart), melanocortin 4 receptor (
Mc4R), neuropeptide Y (
NPY), Y2 receptor, cannabinoid receptor CB1 (
Cnbr1), and the genes of the circadian clock. These genes have several common features, including high levels of expression in
the hypothalamus and the ability to regulate other major physiological functions in addition to bone remodeling including
energy homeostasis, body weight, and reproduction. We review the major pathways that define the new field of neuroskeletal
biology and identify further avenues of inquiry.
Keywords Skeleton - Bone - Adrenergic receptor - Peptin - Sympathetic nervous system