Better medicines are needed to relieve pain

The moment 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.