Figure 2:

Mrgprb2 on mast cells can be activated by variety of endogenous and exogenous positively charged activators (e.g. neuropeptide substance P, drugs, chemical irritants, AMP, QSM, etc). The activation of Mrgprb2 on mast cells leads to the release of protease, cytokine, chemokines and recruitment of other immune cells. There are also mutual interactions between mast cells and sensory nerves in the skin leading to itch and pain.