Splenic schooling dampens inflammation

When confronted with potentially lethal bacterial sepsis, the brain tells the spleen to shut down the production of inflammatory cytokines, according to Huston and colleagues on page 1623. This may help explain why splenectomy renders people more prone to the immunological overreaction of septic shock when infected with certain types of bacteria.

When the brain detects inflammation or injury, it sends signals along the vagus nerve—the meandering nerve that regulates vital functions such as heart rate and digestion. This signal triggers the release of the neurotransmitter acetylcholine (Ach) from peripheral nerve endings. Ach then binds to its receptor on immune cells and inhibits the production of inflammatory cytokines, in part by inhibiting the activation of the transcription factor NF-κB. This circuit is known as the cholinergic antiinflammatory pathway.

Electrical stimulation of the vagus nerve suppresses cytokine...