GRPR and atopic eczema: To test whether this synaptic facilitation to GRPR+ neurons is also observed in other models of chronic itch, we used the inbred strain NC/Nga mice, a model of atopic dermatitis, in which spontaneous scratching is observed when maintained under conventional (CV-NC/Nga), but not under specific-pathogen-free (SPF-NC/Nga) conditions19.