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.

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.

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.

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.

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.”...