Chemical substance inside a cell that carries information farther along the signal pathway from the internal part of a membrane-spanning receptor embedded in the cell membrane, increasing or decreasing responsiveness to stimulus due to an agonist. It may be in the form of an enzyme's product or ion fluxes.

SECOND MESSENGER: "The second messenger has an amplification effect in certain instances."
Cite this page: N., Pam M.S., "SECOND MESSENGER," in, April 28, 2013, (accessed April 18, 2021).