New substances that activate adrenaline receptors instead of opioid receptors have a similar pain-relieving effect, without the negative side effects such as hypoventilation and addiction, reports the Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU).
Opioids are frequently used in healthcare as pain relievers, due to their effectiveness. But they come with a downside, especially morphine which can mean side effects such as nausea, dizziness or hypoventilation – and above all – a strong addiction. In order to overcome the downsides of today's painkillers, researchers have investigated alternative methods.
Adrenaline instead of opioids
A research team at FAU, together with colleagues in China, Canada and the USA, has focused on a receptor that binds adrenaline. There have already been painkillers that work through this receptor, but these have a strong sedative effect, which means that their use has been limited to intensive care in hospitals, and has not been an option for a wider patient group.
The research has therefore focused on finding a molecule that can activate this receptor without the calming effect. After a thinning process of molecules found in a virtual database, two molecules were found with good binding ability and which only activated a selective amount of cellular signaling pathways.
After further optimization, the researchers succeeded in synthetically producing an agonist that stimulates the brain in a way that effectively reduces the experience of pain in animal models. According to Peter Gmeiner, one of the researchers behind the study, a series of tests could confirm that it was precisely the effect they succeeded in making on the receptors that is the cause of the pain-relieving effect.
Great progress
The separation of analgesic and sedative properties is a major advance in the development of non-opioid drugs, especially since the newly identified agonists are relatively easy to prepare and administer orally to patients. Gmeiner points out, however, that even though it can be seen as a major breakthrough, it will take time before new medicine ends up on the market. The project is at the basic research stage, and there are more layers of study that new drugs need to go through, on top of requiring a significant amount of funding.
