Researchers at the Salk Institute have identified two distinct neural pathways in mice for encoding mechanical and chemical sensations of itch. Mechanical itch arises from physical stimuli, while chemical itch is triggered by irritants like insect bites. This groundbreaking discovery demonstrates that specific neurons transmit mechanical itch signals from the spinal cord to the brain independently from those encoding chemical itch sensations. The study found that by manipulating certain pathways in the brain, researchers could activate mechanical itch, revealing the key differences between the two sensory pathways.
This work, published in the journal Neuron, provides insights crucial for developing therapies for chronic itch conditions such as eczema and psoriasis. Scientists Martyn Goulding and Sung Han led the investigation, leveraging genetic techniques and innovative microscopy to observe neuronal activity in real-time. They noted that, intriguingly, sensitizing one pathway could lead to a pathological itch state, implying a collaborative role in chronic itch scenarios.
Future research aims to explore how these pathways converge in the brain and their relationship to pain. The researchers are also interested in understanding how aging affects itch perception, given the rising prevalence of chronic itch among older adults. Overall, these findings pave the way for novel therapeutic interventions for chronic itch disorders.
