Better medicines are needed to relieve pain

you pick up the red-hot saucepan, nerve endings in your skin will register the sudden, potentially traumatic spike in temperature. Heat-sensitive proteins on those nerve endings will respond by changing their shape, allowing sodium and calcium ions to flood into the skin’s nerve cells. Once enough charge has accumulated, electrical signals will fire along a relay of nerve fibres until they reach the spinal cord and, eventually, the brain. There, different regions will be notified: the sensory cortex, for example, will locate the injury; the limbic system will assess its severity. This entire sequence will take a split second (or less); its subjective sensation—sharp, searing pain.The immune system, meanwhile, will kick off inflammation in the skin that is in contact with the hot saucepan. This not only reddens the affected area and makes it sensitive to touch, but also amplifies the pain signals travelling to the brain. Once the brain has registered the pain and worked out a defence—in this case to immediately drop the hot saucepan onto the floor—it will then send its own signals back to the fingertips, attempting to damp down the unpleasant feelings of pain and allow the healing process to start.