Scientists have discovered a method of activating opioid receptors in the brain using light, according to a new study published in Neuron.
The researchers combined the rhodopsin protein, which senses light in the retina of the eye, with a Mu opioid receptor. The resulting was a receptor that responds to light in the same way that standard opioid receptors respond to opiate drugs like morphine or OxyContin.
Opioid receptors have several functions in the body aside from their role in stopping pain: They are also involved in breathing, the gastrointestinal tract, and reward response. The researchers used light as a way to limit these receptors to performing one task at a time. In this case, they sought to mimic how opioid receptors respond to pain-killing drugs.
In a test tube, the researchers exposed their receptors to light. The receptors reacted by releasing the same chemicals usually realized by standard opioid receptors. When the receptors were injected into the brains of mice, the researchers were able to use light to stimulate a reward response.
Typically, opioid drugs have been the best option for patients suffering from severe pain. However, these drugs come with the potential for abuse and side effects. With more testing, the researchers hope that they can treat pain using light instead of these potentially dangerous drugs.
Despite the abuse potential of opioid drugs, they have long been the best option for patients suffering from severe pain. The drugs interact with receptors on brain cells to tamp down the body’s pain response. But now, neuroscientists at Washington University School of Medicine in St. Louis have found a way to activate opioid receptors with light.
In a test tube, the scientists melded the light-sensing protein rhodopsin to key parts of opioid receptors to activate receptor pathways using light. They also influenced the behavior of mice by injecting the receptors into the brain, using light instead of drugs to stimulate a reward response.
Their findings are published online in the journal Neuron.