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Updated: May 30, 2026

Cheek Injection Model for Simultaneous Measurement of Pain and Itch-related Behaviors
Published on: September 27, 2019
The distinct roles of two GPCRs, MrgprC11 and PAR2, in itch and hyperalgesia
Qin Liu1, Hao-Jui Weng, Kush N Patel
1Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA.
Abstract:
Itch has been defined as an unpleasant skin sensation that triggers the urge to scratch. Primary sensory dorsal root ganglia neurons detect itch stimuli through peripheral axons in the skin, playing an important role in generating itch. Itch is broadly categorized as histaminergic (sensitive to antihistamines) or nonhistaminergic. The peptide Ser-Leu-Ile-Gly-Arg-Leu (SLIGRL) is an itch-inducing agent widely used to study histamine-independent itch. Here, we show that Mrgprs (Mas-related G protein-coupled receptors), particularly MrgprC11, rather than PAR2 (protease-activated receptor 2) as previously thought, mediate this type of itch. A shorter peptide, SLIGR, which specifically activates PAR2 but not MrgprC11, induced thermal pain hypersensitivity in mice but not a scratch response. Therefore, although both Mrgpr and PAR2 are SLIGRL-responsive G protein-coupled receptors present in dorsal root ganglia, each plays a specific role in mediating itch and pain.
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