π-TRTX-Hm3a, a 37-amino acid peptide derived from the venom of the Togo starburst tarantula (Heteroscodra maculata), selectively inhibits the acid-sensing ion channel 1a (ASIC1a) in a pH-dependent manner, with an inhibitory concentration half-max (IC50) of 1-2 nM, and also potentiates the activity of acid-sensing ion channel 1b (ASIC1b) with an effective concentration half-max (EC50) of 46.5 nM [1].