It's a familiar sensation, particularly among lovers of wool sweaters or frequent victims of insect bites, but itchiness and its causes have long been a source of contentious debate among scientists. Researchers at Johns Hopkins University School of Medicine now think they may have come up with an answer to the burning question, “Why do we itch?”
The scientists say they have identified specific nerve cells in mice that are responsible for sending itch signals to the nervous system. Their findings, published in the journal Nature Neuroscience, could settle decades of bickering about how the human body processes feelings of pain versus feelings of itch.
The infighting has been fueled by uncertainty about whether certain nerve cells, equipped to respond to both itchy and painful stimuli, were sending both signals to the brain. Based on these latest findings, researchers concluded that nerve cells with an itch receptor known as MrgA3 send itch messages to the brain whether they're exposed to painful or itchy stimuli.