Plants May Have Brain’s Signal System

A key signaling system in the brain also may exist in plants, suggesting its roots go back to before plants and animals went their separate evolutionary ways, scientists say.

The finding also may help explain why plants produce substances like nicotine, cocaine and caffeine that act on the brain, researchers said.

In the plant Arabidopsis, a laboratory favorite, researchers found genes resembling ones used by animals to make structures called glutamate receptors. These are brain cell “hitching posts” for the substance glutamate. When glutamate binds to its receptors, it relays a signal to the brain cells.

The scientists found evidence that Arabidopsis receptors are part of a signaling system that helps the plant respond to light. So maybe nicotine, cocaine and other plant substances that act on other kinds of receptors in the brain are part of undiscovered signaling systems in plants, the researchers said.

The work is reported in the Nov. 12 issue of the journal Nature by Gloria Coruzzi, a plant molecular biologist at New York University, and colleagues.