A new study involving scientists from IBEC, IQAC/CSIC and CNRS in France uses light-regulated drugs to alleviate the negative emotions associated with chronic pain.
Chronic pain is pain that lasts more than six months. Its origin can be both physiological and emotional, and it is accompanied by symptoms such as hypersensitivity, anxiety and depressive behavior. It has no cure, treatment is difficult, and current drugs don’t alleviate the symptoms.
In the paper published in ACS Central Science, IBEC’s Nanoprobes and Nanoswitches group and their colleagues obtained a series of phenylazopyridines, molecules that act on the mGlu5 receptor – one of two brain receptors related to the sensation of pain and negative emotions – that change their structure when irradiated with light, like a switch.
Tests carried out in zebrafish demonstrated that localized administration of light and these photoswitchable phenylazopyridines enabled them to couple to the neuroreceptors and modulate their activity – in other words, when light is applied to switch them on, the molecules had an effect on mGlu5. By observing the movement of the zebrafish larvae, the researchers could see how the the activated compound affected emotions associated with chronic pain, such as anxiety. Not only that, but further experiments also demonstrated that the action of light and photo-exchangeable molecules in localized tissues, including the brain in mice, can regulate a drug’s analgesic effect.
“The results, despite being at a preliminary stage, demonstrate the possibilities of future development of therapies based on photopharmacology,” says IBEC group leader and ICREA professor Pau Gorostiza.
Xavier Gómez-Santacana, Silvia Pittolo, Xavier Rovira, Marc Lopez, Charleine Zussy, James A. R. Dalton, Adèle Faucherre, Chris Jopling, Jean-Philippe Pin, Francisco Ciruela, Cyril Goudet, Jesús Giraldo, Pau Gorostiza, and Amadeu Llebaria. (2017). Illuminating Phenylazopyridines To Photoswitch Metabotropic Glutamate Receptors: From the Flask to the Animals. ACS Central Science DOI: 10.1021/acscentsci.6b00353
IBEC in the Media: At the weekend, Pau Gorostiza was interviewed on Spain’s National Radio discussing this study. His part starts at minute 33”.