AsianScientist (Aug. 8, 2016) – Researchers in China and the UK have found that a natural substance known to activate pain in the central nervous system actually has the opposite effect in other parts of the body.
The discovery, published in Antioxidants & Redox Signalling, could explain the repeated and costly failure of 20 years of clinical trials.
These trials were for potential pain-killing drugs that targeted Substance P, a naturally-occurring substance. Substance P is produced in both the central nervous system, which consists of the brain and spinal cord, and in our peripheral nervous system, which consists of all the other nerves and nerve cells that send signals to the brain.
The present study, by the Hebei Medical University in China and the University of Leeds in the UK, found that Substance P makes nerve cells in the peripheral nervous system less responsive and excitable, thereby reducing sensations of pain. This is in direct contrast to its role in the central nervous system, where it triggers very different signals—exciting neurons and promoting pain.
“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,” explained lead researcher Professor Nikita Gamper from the University of Leeds in the UK.
According to Gamper, this means that 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. As such, the drugs could have appeared to have failed once they reached clinical trial stage.
Gamper believes that this discovery could pave the way for new drugs that don’t have the negative side effects currently associated with stronger painkillers.
The article can be found at: Huang et al. (2016) Redox-Dependent Modulation of T-Type Ca2+ Channels in Sensory Neurons Contributes to Acute Anti-Nociceptive Effect of Substance P.
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Source: University of Leeds; Photo: Shutterstock.
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