A University of Vermont medical doctor and researcher hopes a $308,000, two-year study will be a first step in unlocking one of medicine's oldest puzzles: the mechanisms that might make acupuncture work.

Dr. Helene Langevin, a neuroendrocrinologist and licensed acupuncturist, is studying how the body's tissue responds when pierced by an acupuncture needle.

Acupuncture is the practice, originated in China more than 1,000 years ago, of inserting hair-thin metal needles into the body at specific locations to cure everything from headaches to lower back pain. The practice is widely accepted in China, but it is considered a somewhat unorthodox treatment in the United States

While every practicing acupuncturist can describe the more than 300 exact spots on the body where needles can be placed, no one knows how acupuncture works, or why these special locations are important.

Langevin's study is designed to measure a specific phenomenon that acupuncturists describe as "de qi" (pronounced day-chee). When an acupuncturist inserts a needle into the body in the correct place, the tissue closes around the needle and tugs on it; the reaction is known as "de qi."

"It feels like a fish biting on a fishing line," Langevin said. "It pulls, but it's not muscle contracting -- it's tissue."

Acupuncturists believe this tugging is the body's signal that the correct spot on the body has been pierced and the healing process has been activated.

Langevin's study will measure if this tugging occurs at any spot on the body where acupuncture needles are inserted or whether it occurs only at the special acupuncture points.

Researchers will insert roughly 20 needles in each of 80 volunteers needed for the study. Half of the needles will be placed in acupuncture points, and the other half will be placed in parts of the body not identified as acupuncture points.

"If we find out it's true" that the tug occurs only at acupuncture points, Langevin said, "we'll then be able to investigate the cellular and molecular events that take place" near the needles.

To measure the tug, Langevin's research team had to develop a special instrument that would insert the acupuncture needle with uniform pressure, every time it's used. A human acupuncturist would introduce too much uncertainty into the study, she said.

The instrument also had to measure the force needed to remove the needle. The device contains a computer-controlled miniature motor that can advance and retract an acupuncture needle, as well as measure the tension needed to remove the needle.

Elaine Munro, 46, of Waterbury was Langevin's first research subject Friday. Clad in shorts and a T-shirt, Munro lay on a hospital bed at Fletcher Allen Health Care's General Clinical Research Center while Langevin placed needles at different points in her body.

"I've never had acupuncture before," Munro said. "I was curious."

Munro said sometimes the needles felt like a pinprick, sometimes she couldn't feel them at all, and sometimes the needles hurt. She said she was interested in the study's results because her daughter has rheumatoid arthritis, which requires her to take pain-killing medicine.

"I'm concerned about the long-term effects on the body of taking pain killers," Munro said. "If ... (acupuncture) works, the real benefit is that there's no drugs" involved as pain killers.