More Painful Ligands

Science's STKE  30 May 2000:
Vol. 2000, Issue 34, pp. tw3
DOI: 10.1126/stke.2000.34.tw3

Certain sensory neurons express the cell surface receptor for capsaicin, the agent in hot peppers that causes the sensation of thermal and chemical pain. Capsaicin binds to the intracellular domain of its receptor, a ligand-gated nonselective cation channel, suggesting that there may be endogenous intracellular activators. Hwang et al. demonstrate that certain products of lipoxygenases, called eicosanoids, directly activate the capsaicin receptor. Activation by eicosanoids was blocked by an antagonist of the receptor. Prostaglandins, thought to play a role in mediating inflammatory pain, failed to activate the receptor. Structural similarities between capsaicin and the eicosanoids may explain their use of a common receptor.

Hwang, S.W., Cho, H., Kwak, J., Lee, S.-Y., Kang, C.-J., Jung, J., Cho, S., Minm K.H., Suh, Y.-G., Kin, D., and Oh, U. (2000) Direct activation of capsaicin receptors by products of lipoxygenases: Endogenous capsaicin-like substances. Proc. Natl. Acad. Sci. U.S.A. 97: 6155-6160. [Abstract] [Full Text]