Leech salivary gland peptide with unknown function (PubMed:32524995). It was originally described as exhibiting analgesic function by specifically inhibiting rodent Nav1.8/SCN10A and Nav1.9/SCN11A voltage-gated sodium channels, as well as showing analgesic activities in several mouse models (PubMed:29559913). In a second study, the synthetic peptide has been shown as having very weak activity on Nav1.8/SCN10A at the highest concentration tested (90 uM) and as being only very modestly active at hNav1.9/SCN11A, with a modest peak current size reduction (~19%) at high concentrations (10 uM) (PubMed:32524995). In addition, this second study reports no analgesic activity in a mouse model of inflammatory pain (PubMed:32524995). Expressed in salivary glands. Highly expressed in the head, body and tail with a 2-3-fold higher expression in the head. Does not show effect on voltage-gated calcium channels, potassium channels, and tetrodotoxin-sensitive sodium channels (PubMed:29559913). Does not show activity on Nav1.7/SCN9A, and shows very weak activity on cation channel TRPA1 (PubMed:32524995). Belongs to the annelide toxin family.