From CNI-1493 to the immunological homunculus: physiology of the inflammatory reflex

The inflammatory reflex is a neurophysiological mechanism that regulates the immune system. The efferent branch of the reflex the cholinergic anti-inflammatory pathway, which inhibits inflammation by suppressing cytokine synthesis via release of acetylcholine in organs of the reticuloendothelial system, including the spleen, liver, and gastrointestinal tract. Acetylcholine binds to alpha 7 nicotinic acetylcholine receptors expressed by macrophages and other cytokine-producing cells. Receptor-ligand engagement suppresses proinflammatory cytokines and prevents tissue damage. Herein is a review of some of the experimental studies that define the inflammatory reflex and its anatomic and physiologic components.