The popular pain-relieving medication ibuprofen plays a role in our nervous system. For the first time, researches from the University of Copenhagen have now been able to determine how the drug works in the nervous system. The researchers hope this new knowledge can contribute to the production of better and more targeted pain-relieving medication in the future.

"For the first time we are able to give a full picture of how ibuprofen affects the acid receptor in the nervous system. We have examined in more detail the acid receptor that is activated each time we feel pain or in case of cell death, e.g. following a stroke. We have learned that ibuprofen, roughly speaking, affects the form of the receptor, preventing the signal for activating pain from being sent to the brain," said Associate Professor Stephan Alexander Pless from the Department of Drug Design and Pharmacology, who is behind the new study.

With a view to establishing the effect of ibuprofen on the nervous system the researchers produced a series of slightly different versions of the acid receptor. Here they examined the activity in the cell before and after adding ibuprofen and minutely detailed the interaction. In the process they had to use a new method involving fluorescent substances, as the receptors are so small that they are invisible to the naked eye. But using the fluorescent technique, which makes the receptors light up, the researchers have gained further insight into the process and the movement of the receptors.

The researchers discovered that the effect of ibuprofen is caused by the receptor taking on a new form. Normally the receptor takes on a special form, which the cell recognises as pain-inducing. Then the cell sends signals to the brain and pain is felt. If ibuprofen is added, however, the receptor takes on a different form. This means that the cell is unable to recognise it as pain-inducing and therefore fails to send signals to the brain.

The researchers hope their discovery can help target and refine the development of pain-relieving drugs in the future.

"As researchers we are constantly trying to learn and gain new knowledge on drugs and their effects. Ibuprofen is a medication used by many people, and we are therefore interested in getting the full picture of how it affects the body. For the first time we now have detailed knowledge of how it works, and naturally we hope others will be able to use this knowledge constructively in the future to develop new and more targeted drugs," said Stephan Pless.

The study titled, "Molecular basis for allosteric inhibition of acid-sensing ion channel 1a by ibuprofen," was published in the Journal of Medicinal Chemistry.