New epilepsy drug is possible. (Biomedicine).

Epilepsy affects more than 2 million people in the United States alone, and existing medications don't always safely control the seizures that mark the disorder. A drug mimicking a natural substance in the brain may offer a new therapy.

In the 1990s, Andrey M. Mazarati of the University of California, Los Angeles and his colleagues found that administering a small protein called galanin arrests epileptic seizures in mice. Galanin is a neuropeptide, a molecule used in small concentrations by the brain's nerve cells.

Galanin itself would make a poor drug, however. It doesn't easily cross from the bloodstream into the brain, which is why Mazarati had to inject the neuropeptide directly into the brain, and it's destroyed quickly by enzymes in the body.

Working with researchers in Sweden, Mazarati has begun testing a synthetic molecule with a structure similar to galanin's. Unlike the neuropeptide, this compound, dubbed galnon, can be injected into the bloodstream and make its way into the brain. It's also resistant to degradation by natural enzymes.

Most important, galnon binds to the same brain-cell-surface proteins, or receptors, that galanin does and prevents seizures. In one widely used mouse model of epilepsy, galnon is actually more effective than diazepam, a common seizure medication. Noting that his Swedish colleagues plan to improve galnon's binding to brain-cell receptors, Mazarati calls the synthetic molecule a prototype for a new class epilepsy drugs. --J.T.