BALTIMORE — Almost anyone who has faced a test or a deadline probably wished there was a smart pill to pop.

New research suggests this might eventually be possible.

University of Maryland scientists have linked a brain compound called kynurenic acid to cognition, potentially opening the door to development of a drug that could aid learning in healthy people — and in those with disorders such as Alzheimer's disease.

"Workers might want to take a pill so they can work harder, and college students would be interested because they already are taking amphetamine-type pills so they will be sharper," said Robert Schwarcz, professor of psychiatry, pediatrics and pharmacology and experimental therapeutics at the University of Maryland School of Medicine.

There are many other research projects around the country into brain function. They are examining a wide variety of factors — vitamin supplements, estrogen, herbs, red wine — as well as ways to bolster blood circulation and chemicals that initiate actions in the brain. Several drugs are already being used to improve cognition in Alzheimer's patients, but they aren't effective for every patient.

The odds are long for any new drug treatment gaining government approval for use in humans, but Schwarcz believes the kynurenic acid discovery could be the breakthrough needed by pharmaceutical companies to produce a commercial product. No human tests have been performed based on the findings, but he believes at least four major companies have picked up on his research and have begun active drug development programs.

Other scientists think the research shows promise in a sorely needed area.

"There may be no more important target than how to address impaired cognition in humans," said Dr. William T. Carpenter, director of the Maryland Psychiatric Research Center.

Schwarcz and other scientists have been studying the link for more than a decade and can now show that mice genetically engineered to produce 70 percent less kynurenic acid had markedly improved cognition. They were better able to explore and recognize objects, remember unpleasant experiences and navigate a maze.

In humans, the acid is produced after consuming food containing tryptophan, such as turkey. Tryptophan is an amino acid essential to the human diet because it helps the body produce serotonin, which promotes healthy sleep and stable mood. Conversely, abnormally high levels of kynurenic acid are found in people with brain disorders. Further, more acid is produced with age.