This peptide activates human and mouse sensory neuron-specific G-protein coupled receptors MRGPRX1 (PubMed:30243794). The activity on human receptors has been measured (EC(50)=1.8 uM) (PubMed:30243794). Compared with the agonist chloroquine (anti-malaria drug), it is 200-fold more potent (PubMed:30243794). The peptide also causes an increase in cytosolic calcium in a specific subset of DRG neurons, and, in contrast to other Conus venom peptides, the peptide also affects a large fraction of the non-neuronal cells (PubMed:25464369). In vivo, when intracranially injected into mice, it principally renders mice unable to move, and at very low doses, it causes hyperactivity (PubMed:25464369). It also induces itch sensation, since intradermal cheek injection into humanized transgenic mouse (mouse MRGPRX1 replaced by human MRGPRX1) induces scratching (PubMed:30243794). In vivo, when tested at high doses (10 uM) on zebrafish larvae, it induces a range of behavioral effects ranging from an early hypoactivity during the first hour of treatment to an increase in movement during the following hours when the larvae are submitted to strobe light phases (PubMed:33764053). Expressed by the venom duct. The mature peptide does not contain cysteine residue. Belongs to the FARP (FMRFamide related peptide) family. Paths of discomfort - Issue 212 of March 2019