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Novel approach to soothing pain therapy
Many diseases are accompanied by chronic pain, which is an additional burden for those affected in everyday life. Scientists at the Friedrich Alexander University (FAU) Erlangen-Nuremberg have now discovered a new approach to effectively relieve the pain of certain diseases.
Capsaicin is known as an ingredient of chilies and responsible for their sharpness. However, the substance can also help, for example, with the pain of a so-called post-zoster neuralgia after shingles, reports the FAU. But here are often side effects such as a strong burning determine. However, the researchers were able to identify a substance "that could also be used to fight severe pain - but is far more tolerable," the university said. Their findings were published in the scientific journal "Scientific Reports".
Scientists discover new approach to treating chronic pain. (Image: psdesign1 / fotolia.com) Nociceptors responsible for pain sensation
The mediation of sensations of pain is controlled in the body by special nerve fibers, the so-called nociceptors. If the nociceptors are activated, they release, inter alia, pro-inflammatory neuropeptides, explain the researchers. Harmful influences are detected by the nociceptors with the help of a large number of receptors on their surface. For example, the capsaicin receptor channel reacts strongly to the sharp ingredient of the chili peppers. Another of these receptors is activated by mustard, horseradish or onions, which is why the scientists call this "mustard oil receptor" - the scientific term is "TRPA1". According to the scientists, this receptor also plays a key role in painful inflammation of the colon and pancreas and in asthma.
Chronic colonic inflammation prevented
In their current study, the researchers examined Dr. Matthias Engel of the Department of Internal Medicine I, and Prof. Dr. med. Peter Reeh from the Institute of Physiology and Pathophysiology at FAU, the effect of the substance capsazepine, which partially blocks the "chili receptor". In earlier studies, the use of capsazepine had prevented the development of chronic colitis (ulcerative colitis) in mice, explain the doctors. Which processes were responsible for this, however, remained unclear. This must be due to an unknown side effect of capsazepine, because the capsaicin receptor is not involved in the disease process of this inflammation, emphasizes Dr. med. Angel.
Scientists have also shown in earlier work that a synthetic inhibitor of mustard oil receptor not only prevent the colonic disease, but even cure, reports the FAU. So the researchers now suspected that capsazepine could have such an inhibitory side effect on the mustard oil receptor. The result of their investigation, however, was a surprise. Instead of being inhibited, the receptor was activated by the drug - and most effectively. This in turn made the receptor insensitive to the irritant. Thus, capsazepine developed its protective effect because the nociceptors reacted less to corresponding stimuli and no longer released neuropeptides, the researchers explain.
Desensitization throughout the body
The scientists were also able to determine that the release of the neuropeptides, for example, in the skin decreased, although the capsazepine was administered only locally in the intestine. Apparently, capsazepine can effectively reach all nociceptors in the body via the bloodstream and desensitize accordingly. Here, the researchers also see opportunities for therapeutic use as a remedy for severe pain. It has long been known that nociceptors can be desensitized by large doses of capsaicin throughout the body, but there was the problem of massive side effects.
New approaches to pain therapy
By taking large amounts of the chili drug, the body can no longer regulate the temperature well, the sensation of painful heat is lost and the blood circulation of some organs is worse, explain the scientists. All these side effects are permanent and irreversible, which is why capsaicin in humans is used only locally with patches and in low dose in creams. However, with several days of capsazepine given in a high but well-tolerated dose, the sensitivity to painful chemical and heat stimulation was gradually reduced throughout the body and concurrent prevention of colitis. This is a promising finding that could help in the long term to develop highly effective painkillers for diseases where the mustard oil receptor plays an important role, according to the FAU. As such diseases, in addition to the chronic colitis, for example, joint arthrosis, chronic pancreatitis, Crohn's disease or chronic asthma may be mentioned. (Fp)