Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Light-activated compound silences nerves, may one day help epileptics

08.03.2007
Brain activity has been compared to a light bulb turning on in the head. Scientists at Washington University School of Medicine in St. Louis have reversed this notion, creating a drug that stops brain activity when a light shines on it.

The unexpected result, reported online in Nature Neuroscience, turned several lights on in researchers' heads.

"This is daydreaming at this point, but we might one day combine this drug with a small implanted light to stop seizures," says senior author Steven Mennerick, Ph.D. associate professor of psychiatry and of anatomy and neurobiology. "Some current experimental epilepsy treatments involve the implanting of an electrode, so why not a light?"

The new compound activates the same receptor used by many anesthetics and tranquilizers, making it harder for a brain cell to respond to stimulation. Mennerick and colleagues including lead author Larry Eisenman, M.D., Ph.D., assistant professor of neurology, tested the drug on cells in culture set up to behave like they were involved in a seizure, with the cells rapidly and repeatedly firing. When they added the new drug and shone a light on the cells, the seizure-like firing pattern calmed.

If the drug is adapted for epilepsy, Mennerick notes, it is most likely to help in cases where seizures consistently originate from the same brain region. Theoretically, doctors could keep a patient on regular doses of the new drug and implant a small fiber optic light in the dysfunctional region. The light would activate the drug only when seizure-like firing patterns started to appear.

Scientists in the laboratory of Douglas F. Covey, Ph.D., professor of molecular biology and pharmacology, created the drug by linking a steroid known to have anesthetic effects with a molecule, known as NBD, that fluoresces in response to blue light. Mennerick and colleagues were hoping to use the new compound, which they call the NBD-steroid, to trace the steroid's path in the nervous system.

To their initial disappointment, the researchers found that adding the fluorescent tag to the steroid had disabled it.

"Normally, the steroid keeps the cell quiet in the face of stimuli that would otherwise cause it to fire," Mennerick says. "That's why drugs like barbiturates and Valium, which act on the same receptor as the steroid, are sedatives—they quiet the nerve system down."

When dosed with NBD-steroid, nerve cells still responded to stimuli as readily as they had prior to exposure. Just to see where the modified steroid was going, though, researchers exposed the cells to light.

"All of a sudden, the response to the steroid was back, and the nerve cells were more reluctant to react to stimuli," Mennerick says. "And we knew we had found something very interesting."

To confirm what was happening, scientists dosed two of a nerve cell's many different branches with NBD-steroid. When they shone a light on one of the branches, its readiness to respond decreased, while the readiness of the branch not exposed to light remained the same.

Department of Anesthesiology colleagues tested the compound's effects on tadpoles.

"Tadpoles rapidly take up drugs through their skin, so they're frequently used to test potential anesthetics," Mennerick notes. "And of course, given that it's a photoactive drug, they make a nice test subject because they're mostly translucent."

Tadpoles swimming in a solution of NBD-steroid went to sleep at the bottom of their beaker when exposed to light.

Mennerick and his colleagues are currently seeking to identify or create an animal model of epilepsy that lets them test the NBD-steroid's potential as a therapeutic.

They are also looking for a new fluorescent tag that responds to longer wavelengths of light. Unlike many photoactive compounds, the NBD-steroid responds not to ultraviolet light but to light from the blue region of the electromagnetic spectrum. This helps because the longer wavelengths of blue light penetrate farther into tissue than ultraviolet light and are less damaging to it. Molecules that fluoresce in response to even longer wavelengths of light are available, and scientists are testing whether any of them can create the same effect when bound to the steroid.

Michael C. Purdy | EurekAlert!
Further information:
http://www.wustl.edu

More articles from Health and Medicine:

nachricht Millions through license revenues
27.04.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht New High-Performance Center Translational Medical Engineering
26.04.2017 | Fraunhofer ITEM

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>