Last Updated: 2003-07-03 14:00:08 -0400 (Reuters Health)

NEW YORK (Reuters Health) - A technique that improves the body's ability to discern touch is either boosted or dampened by two different drugs, according to research released Thursday.

The findings could lead to new ways to treat sensory problems in the elderly, stroke patients and others, investigators say.

In the study, researchers in Germany found that the effects of a technique called coactivation -- which improves the sense of touch in the fingertips -- were increased by the drug amphetamine, and decreased by a drug that blocks a type of receptor in the brain called N-methyl-D-aspartate (NMDA).

Study participants underwent three hours of coactivation, in which a tiny disk was used to stimulate the skin on the right index finger. The technique temporarily boosted participants' sense of touch, an improvement that was either helped or hindered by the two drugs.

Coactivation essentially "shuffles" the synapses that link nerve cells in the brain, increasing the number of cells involved in processing tactile sensations.

Study author Dr. Hubert R. Dinse told Reuters Health that coactivation "was developed to purposely alter brain organization and thus behavior and perception."

"According to our new findings," he explained in a statement, "certain drugs can enhance the effects of coactivation. The drug component makes this coactivation approach even more promising."

He and his colleagues believe the approach might prove helpful for people with disturbances in the body's sensory "maps," such as amputees, stroke patients and those with chronic pain.