Light Activates Pain Nerve Cells With New Compound Tested by Scientists

Researchers searched for and found a compound that lets nerve cells, located anywhere on the body outside the eyes, react to light. Massachusetts General Hospital's David Kokel and colleagues identified the drug-like molecule named "optovin", which elicits movements in mice and fish when exposed to flashes of light.

Similar experiments have been conducted with a light-based technique known as optogenetics, but the new method doesn't require researchers to genetically engineer animals to achieve the neural control, MIT Technology Review reports.

The techniques is meant as a useful research tools for understanding nerve cells, neurons and the brain, which may also one day be used therapeutically.

Zebrafish embryos in a small tank enriched with the chemical will move around very quickly in response to a flash of light, which triggers likely a feeling of pain, the researchers reported. They tested over 10,000 chemicals in this way until finding optovin. A downside is that it only works on this one kind of neurons and nerve cells, a disadvantage to optogenetics which can manipulate all kinds of neurons with light - after genetically modifying them that is.

Kokel found that optovin docks onto a specific kind of protein channel that sits in the membrane of nerve cells that are the first to respond to pain. Researchers could use optovin in experiments to study pain; they also think it could be useful in treating pain one day, because "if you over-activate these channels, they become desensitized," Kokel says.

Paper:
David Kokel et al., Photochemical activation of TRPA1 channels in neurons and animals, Nature Chemical Biology, 2013, DOI: 10.1038/nchembio.1183