second messenger

noun

, Biochemistry.

1. any of various intracellular chemical substances, as cyclic AMP, that transmit and amplify the messages delivered by a first messenger to specific receptors on the cell surface.

second messenger

1. A molecule that relays messages in a cell from a receptor on a cell membrane to the final destination where an action within the cell is to take place. ( See signal transduction pathway .)

Word History and Origins

Origin of second messenger¹

First recorded in 1960–65

Example Sentences

The latest data suggest Johnson & Johnson recipients should get a booster with one of the messenger RNA vaccines, if they haven’t already done so — and even consider a second messenger RNA booster for the greatest protection.

From Washington Post

The entire circuit is modulated by the protein TCF7L2 that, acting through a second messenger molecule called cAMP, mediates the sensitivity of nAChR-expressing neurons to nicotine.

From Nature

What’s more, Tiuri’s quest turns out to have been slightly redundant: A second messenger was wisely, if anti-dramatically, entrusted with the same message.

From New York Times

The first messenger’s arrival at the outer wall of the cell eventually causes production within the cell of a “second messenger,” which prompts the cell to act.

From Washington Post

A second messenger announced that they had begun their march; our brazen drum was sounded, all were alert, the sultan came out, and I accompanied him: he surrounded them with chosen troops, and gave the signal for attack.”...

From Project Gutenberg