Chronic itch is a debilitating symptom that accompanies skin conditions such as atopic dermatitis (AD) and allergic contact dermatitis.

Previous studies have established that inflammatory mediators in the skin stimulate the sensory neurons that produce an itch, but the molecular pathways behind chronic itching remain largely unknown.

The researchers examined cysteinyl leukotrienes (CysLTs)—lipid signaling molecules thought to mediate allergic skin reactions—and found that a signaling molecule called LTC₄ has a functional role in chronic itching.

The authors report that the CysLT receptor 2 (CysLT₂R) is highly expressed in dorsal root ganglia (DRG) associated with itching in mice and is expressed more broadly in human DRG neurons.

Furthermore, using an AD mouse model, the authors found that the CysLT signaling pathway, specifically the coupling of LTC₄ with CysLT₂R, produces scratching in mice in a dose-dependent manner, but without corresponding pain behaviors.

According to the authors, LTC₄ may provide a link between immune cells and sensory neurons in mice and may represent a therapeutic target for chronic itch associated with inflammatory skin pathologies in humans. 

https://www.pnas.org/content/118/13/e2022087118

http://sciencemission.com/site/index.php?page=news&type=view&id=publications%2Fthe-cyslt2r-receptor&filter=22