How Nerve Cells Grow

Published: July 24, 2003  |  Source: healthscout.com
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FRIDAY, July 25 (HealthDayNews) — Researchers at Johns Hopkins Medical Institutions have identified a protein that promotes the growth of tentacle-like axons on nerve cells.

The finding could eventually help scientists develop ways to rebuild nerves lost to spinal cord injuries or degenerative conditions such as Huntington’s disease. Researchers have spent decades trying to find signals that guide axons and lets these cell tips reach out to distant targets.

The Johns Hopkins team made their finding while studying a family of proteins that are best known for repelling axons and inhibiting their growth. Unexpectedly, they found one member of those proteins — semaphorin-7a — actually promotes the growth of axons.

In laboratory experiments, they found that rat nerve cells grew more and longer axons on the side nearest the source of the semaphorin-7a protein. They also found that in mice that lacked semaphorin-7a, axons of some odor-sensing nerves never reached their targets.

The study appears in this week’s issue of Nature.

“I’ve been studying semaphorins for about a decade and didn’t expect to find any that stimulated Axon growth, certainly not to the extent we saw in the lab and in mice,” Alex Kolodkin, a professor of neuroscience, says in a news release.

The researchers say they need to determine how semaphorin-7a’s message is passed along inside the nerve. Understanding that could help them find a specific target for promoting axon growth following nerve injury or degeneration.

More information

Here’s where you can learn more about degenerative nerve diseases (health.nih.gov).

–Robert Preidt
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Last updated 7/25/2003