Dynamic norepinephrine alterations in bone marrow: evidence of functional innervation

Area of Science:

• Neuroimmunology
• Hematology

Background:

• Efferent sympathetic nerve activity is hypothesized to regulate leukocyte proliferation and maturation in bone marrow.
• Histological evidence for bone marrow innervation exists, but functional activation remains unproven.

Purpose of the Study:

• To assess norepinephrine (NE) release dynamics in bone marrow in response to stimuli that elevate sympathetic activity.
• To demonstrate functional activation of bone marrow adrenergic nerves.

Main Methods:

• Norepinephrine turnover was measured using isotopic and non-isotopic methods in mice.
• Stimuli included cold exposure and bacterial challenge (Pseudomonas aeruginosa infection).

Main Results:

• Cold exposure increased bone marrow NE turnover rate by 36%.
• Bacterial infection significantly increased bone marrow NE turnover rate by 131%.
• Demonstrated functional responsiveness of bone marrow adrenergic innervation.

Conclusions:

• Bone marrow adrenergic innervation is functionally dynamic and responsive to generalized stress.
• Neural mechanisms likely participate in regulating lympho- and myelopoietic cellular events.