Dopamine Used To Prompt Nerve Tissue To Regrow

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Dopamine Used To Prompt Nerve Tissue To Regrow

http://www.sciencedaily.com/releases/2006/11/061102125452.htm

When Yadong Wang, a chemist by training, first ventured into nerve

regeneration two years ago, he didn't know that his peers would have

considered him crazy.

His idea was simple: Because neural circuits use electrical signals

often conducted by neurotransmitters (chemical messengers) to

communicate between the brain and the rest of the body, he could

build neurotransmitters into the material used to repair a broken

circuit. The neurotransmitters could coax the neurons in the damaged

nerves to regrow and reconnect with their target organ.

Strange though his idea might have seemed to others in his field,

Wang, an assistant professor in the Wallace H. Coulter Department of

Biomedical Engineering at Georgia Tech and Emory University,

discovered that he could integrate dopamine, a type of

neurotransmitter, into a polymer to stimulate nerve tissues to send

out new connections. The discovery is the first step toward the

eventual goal of implanting the new polymer into patients suffering

from neurological disorders, such as Alzheimer's, Parkinson's or

epilepsy, to help repair damaged nerves. The findings were published

online the week of Oct. 30 in the Proceedings of the National

Academy of Sciences (PNAS).

" We showed that you could use a neurotransmitter as a building block

of a polymer, " said Wang. " Once integrated into the polymer, the

transmitter can still elicit a specific response from nerve

tissues. "

The " designer " polymer was recognized by the neurons when used on a

small piece of nerve tissue and stimulated extensive neural growth.

The implanted polymer didn't cause any tissue scarring or nerve

degeneration, allowing the nerve to grow in a hostile environment

post injury.

When ready for clinical use, the polymer would be implanted at the

damaged site to promote nerve regeneration. As the nerve tissue

reforms, the polymer degrades.

Wang's team found that dopamine's structure, which contains two

hydroxyl groups, is vital for the material's neuroactivity. Removing

even one group caused a complete loss of the biological activity.

They also determined that dopamine was more effective at

differentiating nerve cells than the two most popular materials for

culturing nerves — polylysine and laminin. This ability means that

the material with dopamine may have a better chance to successfully

repair damaged nerves.

The success of dopamine has encouraged the team to set its sights on

other neurotransmitters.

" Dopamine was a good starting point, but we are looking into other

neurotransmitters as well, " Wang said.

The team's next step is to verify findings that the material

stimulates the reformation of synapses in addition to regrowth.

" A successful nerve regeneration will require the nerve to synapse

with the target organ, " Wang said. " Since we've written this paper,

we've also been able to get the nerves to form extensive synapses,

which is a step in the right direction. "