The neuropeptide alpha-melanocyte-stimulating hormone: a key component of neuroimmunomodulation.

Recent research indicates that the proopiomelanocortin derivative alpha-melanocyte stimulating hormone (alpha-MSH) is a significant modulator of host reactions including fever and inflammation. Although the precise mechanism of action is still unknown, cytokine antagonism is believed to be responsible for at least a part of its anti-inflammatory/antipyretic influence: alpha-MSH antagonizes pyrogenic and proinflammatory effects of cytokines such as interleukin-1 (IL-1), interleukin-6 (IL-6), tumor necrosis factor (TNF), and interferon gamma (IFN gamma). Although it is clear that the peptide can act within the brain to inhibit fever and peripheral inflammation, an anti-inflammatory effect on a peripheral target was evidenced in animals with transection of the spinal cord. Recent data show that alpha-MSH is significant also in human disorders such as AIDS, rheumatoid arthritis, and myocardial infarction. This molecule is believed to be a key factor in neuroimmunomodulation and it may be useful as a therapeutic agent in control of inflammatory reactions.