Painful protein
Scientists in the US have discovered a protein in nerve cells that can act as a switch for chronic pain. The switch is called protein kinase G (PKG). This could lead to the development of a new class of drugs for blocking chronic pain.
The researchers, from Columbia University Medical Center (CUMC), found that PKG is activated by injury or inflammation, and passes the pain message to the brain. Turning the PKG off relieves the pain and makes it a good target for therapy. This pathway was described earlier in invertebrates but the Columbia group has worked on rats that have a nervous system that is closer to humans.
None of the existing drugs are adequate to deal with chronic pain because of side effects, which include getting addicted to them. Painkillers available in the market target neurons in the spinal cord that relay pain messages to the brain. But this means that the drug has to overcome the blood-brain barrier.The CUMC researchers have focused on the neurons near the skin that send messages to the spinal cord. The study will appear in the forthcoming issue of Neuroscience. The group has applied for a patent for the pathway that turns on the PKG, as well as several molecules that inhibit it.