May be directly involved in a paralyzing effect, by inhibiting muscle contraction, or may also act centrally to modulate prey behaviors (Probable). The non-amidated form (Sa12b) potently inhibits ASIC current in rat DRG neurons (IC(50)=81 nM) when preincubated before activation by acidic pH (PubMed:31658776). Has no consistent action on the time course of desensitization or the sustained component of the current (PubMed:31658776). Has no activity when coapplied with acidic pH, suggesting that the peptide needs to interact with the channel during its closed state (PubMed:31658776). This effect is concentration-dependent and reversed after washout of the peptide (PubMed:31658776). Since the inhibition is almost complete at 1 uM and all ASIC subunits are expressed in dorsal root ganglion (DRG) neurons, it suggests that it inhibits different ASIC subunits without an apparent selectivity (PubMed:31658776). It is noteworthy that it does not show activity on the locust oviduct contraction (tested at 50 nM), in contrast to the amidated form (Ref.2, PubMed:34023397). The amidated form (Sa112) inhibits both the frequency and amplitude of spontaneous contractions of the locust oviducts (tested at 50 nM). Expressed by the venom gland. Is either amidated (Sa112) or non-amidated (Sa12b). amidated form (Sa112), Monoisotopic mass. non-amidated form (Sa12b), Monoisotopic mass. Belongs to the FARP (FMRFamide related peptide) family.