4,9-Anhydrotetrodotoxin (4,9-anhydro-TTX) is a derivative of TTX that selectively blocks inward sodium current through Nav1.6 voltage-activated sodium channels (IC50 = 7.8 nM in Xenopus oocytes). [1][2][3] It demonstrates IC50 values of 1.3, 0.34, 0.99, 78.5, 1.3, and >30 181M for Nav1.2, Nav1.3, Nav1.4, Nav1.5, Nav1.7, and Nav1.8, respectively.[1]
Mambalgin 1 TFA, a selective inhibitor of ASIC1a (with IC50 values of 192 nM for human ASIC1a and 72 nM for the ASIC1a 1b dimer), preferentially binds to the channel in its closed inactive state. It demonstrates selectivity for ASIC1a over a range of other channels, including ASIC2a, ASIC3, TRPV1, P2X2, 5-HT3, Nav1.8, Cav3.2, and Kv1.2. In vivo, Mambalgin 1 TFA effectively prolongs the latency of the withdrawal response in mouse tail-flick and paw-flick tests.