The response to danger: Is it in your bones?

Area of Science:

• Neuroendocrinology
• Neuroscience

Background:

• Osteocalcin is a bone-derived hormone with known systemic effects.
• The ventral tegmental area (VTA) is a key brain region involved in reward and motivation.
• GPR37-expressing neurons in the VTA are implicated in various neurological processes.

Purpose of the Study:

• To investigate the role of circulating osteocalcin in VTA GABAergic neuron function.
• To elucidate the bone-to-brain neuroendocrine circuit's involvement in threat detection.
• To determine the necessity of this circuit for escape responses to visual threats.

Main Methods:

• Utilized rodent models to study the effects of osteocalcin.
• Employed genetic and pharmacological tools to manipulate GPR37+ VTA GABAergic neurons.
• Assessed behavioral responses to visual threat stimuli.

Main Results:

• Demonstrated that osteocalcin maintains GPR37+ VTA GABAergic neurons in a state of readiness.
• Established that this bone-to-brain circuit is essential for rapid visual threat detection.
• Confirmed the circuit's necessity for initiating an effective escape response.

Conclusions:

• The bone-to-brain neuroendocrine circuit involving osteocalcin and VTA GABAergic neurons is critical for survival behaviors.
• Osteocalcin signaling directly impacts neuronal excitability in the VTA, influencing threat perception.
• This study reveals a novel mechanism by which bone influences brain function and behavior.