WEST LAFAYETTE, Ind. -- The medicinal leech, a worm-like creature once used by doctors to bleed patients, now is being used to draw clues on how a common protein may help promote neural regeneration.
Purdue University biologist Christie Sahley and research assistant Orie Shafer have found that nitric oxide synthase, or NOS, is activated when parts of the nerve cell are damaged in the medicinal leech, a three-inch-long invertebrate known for its ability to regenerate its neural connections.
The Purdue group now is conducting follow-up studies to see what role NOS may play in neural regeneration. The findings may someday be applied to research in human spinal regeneration. Details of the study were presented Nov. 21 at the annual meeting of the Society for Neuroscience.
"Our study shows that NOS in the leech is activated at the site of injury within minutes after axons are severed, and it remains active well beyond 48 hours after the injury," Sahley says. Axons are the long "arms" of a nerve cell that carry impulses away from the cell body toward a target cell.
"We are now conducting follow-up studies to identify what information this molecule provides at a cellular level, and to see how these functions might help the leech's nervous system set itself up to allow regeneration to occur," she says.
NOS, an enzyme also found in humans, produces a "signaling" molecule that sends chemical messages throughout the body to incite certain chemical reactions. Because the NOS found in leeches is very much like the human NOS, it may serve a similar function in both species, Sahley says.
"Nerve cells in leeches are basically identical in structure and function to those in more complicated systems such as humans," Sahley says. "But for some reason, nerve regeneration in higher systems is not complete. By analyzing how nerves regenerate in a simple system, we may find clues to facilitate regeneration in vertebrates."