‘Optical switches’ could be used to treat epilepsy
German researchers have found a way to switch sensory neurons on and off using light alone.
The technique, which uses a chemical compound to temporarily make neuroreceptors photosensitive, allows for the direct manipulation of nerve cells, so the brain’s responses to sensory stimulation can be altered at will.
According to the researchers, it could eventually form the basis of new treatments for a range of neurological conditions, among them depression and epilepsy.
Led by chemical biology and genetics professor Dirk Trauner, scientists at Ludwig-Maximilians-Universitat (LMU) in Munich developed a chemically modified version of fentanyl – a synthetic opioid commonly used as an anaesthetic and painkiller.
The compound binds to the brain’s neuroreceptors, making them sensitive to light so their function can be activated and deactivated at will – simply by exposing them to beams of different colours.
According to the researchers, whose paper is published in the February edition of Neuron, this technique could be used to promote or inhibit neurons that are compromised in diseases of the central nervous system like epilepsy.
It could also be used to activate other chemical compounds such as analgesics, cytostatic drugs or anti-diabetic agents at sites where they are required, minimising the unwanted side effects that occur when these drugs are released throughout the body.
Neurons are responsible for all modes of sensory perception, relying on proteins expressed at their surface membranes to respond to stimuli like touch or temperature.
Many nerve cells will only respond to a single type of event, but according to Professor Trauner, the technique developed at LMU enables neuroreceptors to be switched on and off regardless of the stimulus they normally require.
“In the long term, we hope to use this approach as the basis for new therapies for neurological disease,” he commented.
“The properties of light can be very precisely manipulated, so that we can modulate the state of the cells in a defined fashion,” Professor Trauner continued. “Furthermore, the reaction is fully reversible.”
Posted by Steve Long