Peptide offers hope for new pain control treatments
17 Aug 2016 by Evoluted New Media
A natural substance that activates pain receptors in the central nervous system has been found to have the opposite effect in other parts of the body, leading to hopes it could be used for new pain control methods.
A natural substance that activates pain receptors in the central nervous system has been found to have the opposite effect in other parts of the body, leading to hopes it could be used for new pain control methods.
‘Substance P’, a peptide, is produced in both the central and peripheral nervous system. In the latter, Substance P makes nerve cells less responsive and excitable, reducing sensations of pain.
Professor Nikita Gamper, from Leeds’ School of Biomedical Science and lead researcher, said: “We were really surprised by the results – Substance P is described in the literature as a molecule that gets nerve cells excited and promotes pain. But we’ve discovered a paradox – that in the peripheral nervous system it acts as one of the body’s natural painkillers and actually suppresses pain.”
Substance P has been the target of many potential pain-killing drug trials over the years but the best way utilise it has not yet been found. The study looked at the action of the peptide within nerve cells in the lab and in animal models and focused on acute pain.
Professor Gamper said: “When drugs were used in trials to suppress Substance P’s action in the central nervous system, they may have also prevented it from acting as a painkiller in the peripheral system. So, although the drugs looked like they worked in the lab, when they were moved to clinical trials, they failed.”
The peptide modulates the action of certain proteins that affect the ability of pain-sensing neurons to react to stimuli in the peripheral system. One certain protein affected by Substance P becomes so sensitive to zinc, that natural levels of the element in the body are enough to suppress their neuronal responses.
Researchers believe this discovery could pave the way for new pharmaceuticals that do not have the same side effects as drugs that are currently used. Morphine, as it acts within the CNS, can cause addiction or sleepiness. Professor Gamper said: “If we could develop a drug to mimic the mechanism that Substance P uses, and ensured it couldn’t pass the blood brain barrier into the central nervous system, so was only active within the peripheral nervous system, it’s likely it could suppress pain with limited side effects.”
Trials will continue in order to ascertain the role of Substance P in chronic pain. The study was published in Antioxidants and Redox Signalling.
