The activation of MrgprX1 degranulates mast cells to communicate with sensory nerve and cutaneous cells for developing neurogenic inflammation. The Mas-related G protein-coupled receptors (Mrgpr) family as well as transient receptor potential ankyrin 1 (TRPA1) and protease activated receptor 2(Par2) have important roles in itch and inflammation. Some receptors are more important than others in the generation of itch. Neuropeptides, like substance P (SP) and calcitonin gene-related protein (CGRP), are produced by sensory nerves in the dermis they induce mast cells to release vasoactive amines that facilitate infiltration of neutrophils and T cells.
The epidermis closely interacts with nerve endings, and both epidermis and nerves produce substances for mutual sustenance.
