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Updated: Sep 14, 2025
Cheek Injection Model for Simultaneous Measurement of Pain and Itch-related Behaviors
Published on: September 27, 2019
Imperatorin activates TRPV1/GRPR pathway to induce scratching behaviors in mice
Liyuan Bao1, Xinyi Gao1, Ting Yi1
1Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Institutes of Integrative Medicine, Shanghai Key Laboratory of Acupuncture Mechanism and Acupoint Function, State Key Laboratory of Brain Function and Disorders and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai Medical College, Fudan University, Shanghai, 200032, China.
Imperatorin (IMP) effectively models acute, non-histaminergic itch in mice by activating TRPV1 and GRPR pathways. This preclinical model aids in screening new anti-itch drugs.
Area of Science:
- Neuroscience
- Pharmacology
- Dermatology
Background:
- Chronic itch significantly impacts quality of life and necessitates better preclinical models for drug development.
- Current models often rely on histamine, limiting the scope for non-histaminergic itch research.
Purpose of the Study:
- To establish and characterize a novel preclinical animal model for acute, non-histaminergic itch using imperatorin (IMP).
- To elucidate the underlying molecular mechanisms of IMP-induced itch, focusing on sensory neuron activation and central pathways.
Main Methods:
- Intradermal injection of imperatorin (IMP) in mice to induce itch behaviors (scratching, wiping).
- Assessment of IMP's effects on transient receptor potential ion channel V1 (TRPV1) and G protein-coupled receptor 53 (GRPR) pathways.
- Pharmacological inhibition using a GRPR antagonist (RC3095) and genetic manipulation (TRPV1 deficiency).
Main Results:
- IMP induced dose-dependent scratching, independent of histamine, and wiping behaviors.
- IMP activated TRPV1 channels in dorsal root ganglion (DRG) neurons, evidenced by increased p-ERK and calcium influx.
- TRPV1 deficiency and GRPR antagonism significantly reduced IMP-induced scratching and associated neuronal activation (c-Fos).
Conclusions:
- Imperatorin serves as an effective non-histaminergic model for acute itch.
- The IMP-induced itch pathway involves TRPV1 activation in DRG neurons and subsequent signaling through GRPR neurons in the spinal cord.
- This model is valuable for screening potential anti-pruritic agents targeting non-histaminergic itch mechanisms.
