Tarantula toxins potently target voltage-gated sodium channels (Navs) through binding to voltage sensor domains, and they are powerful tools for the investigation of Nays.In the present study,we isolated and characterized three peptide toxins named JZTX-36,-38 and-39 from venom of Chilobrachys guangxiensis.These toxins could modulate human Nav1.5 currents with different effects on Nav1.5 channel activation and inactivation gating.