– GrTx1, a peptide toxin derived from Grammostola rosea spider venom, selectively inhibits sodium channels Nav1.1, Nav1.2, Nav1.3, Nav1.4, Nav1.6, and Nav1.7, with IC50 values of 0.63 µM, 0.23 µM, 0.77 µM, 1.29 µM, 0.63 µM, and 0.37 µM, respectively [2]. This compound has applications in neurological disease research [1].