Turning Off Pain with the Flick of a Switch

19 February 2014


A team of researchers at Stanford have developed mice whose sensitivity to pain can be spiked up or down by shining light on their paws. Their work could have serious ramifications for helping the millions who suffer from chronic, debilitating pain due to nerve damage.

The mice were modified with gene therapy to have light-sensitive nerves. Light was shone on their paws through the bottom of the glass cage. One color of light made the mice more sensitive to pain. Another color reduced pain.

Light-sensitive proteins, or opsins, are used to control pain with various colors of light.

Light-sensitive proteins, or opsins, were used to control pain with various colors of light.

The work was done in Scott Delp’s lab. “This is an entirely new approach to study a huge public health issue,” Delp said. It opens many doors to furthering our understanding of pain and other sensations. Delp became interested in how pain functions in the nerves outside the brain responsible for muscle and movement.

The injections used on the mice contained light-sensitive proteins, called opsins, to enable both extreme pain sensitivity and pain inhibition due to different light sources. This is the basis of a technique called optogenetics- a process involving the insertion of opsins into the nerves. In Lou Gehrig’s Disease (ALS), the nerves that control movement, pain, and touch, among other sensations, could possibly be treated using optogenetics.

Their work has major implications for pharmaceutical and therapeutic applications. Delp hopes to improve the understanding and even treatment for individuals with chronic pain using new biomedical technologies for imaging, neuromodulation, and optogenetics.

“Developing a new therapy from the ground up would be incredibly rewarding,” Delp said. “Most people don’t get to do that in their careers.”



Alec Schwartz
Biochemistry and Molecular Biology Major
Dickinson College
Class of 2016







Shrivats Mohen Iyer, Kate L Montgomery, Chris Towne, Soo Yeun Lee, Charu Ramikrishnan, Karl Deisseroth & Scott L Delp. (16 Feb 2014). Virally mediated optogenetic excitation and inhibition of pain in freely moving nontransgenic mice. Nature Biotechnology doi:10.1038/nbt.2834 

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