pctx-1

**PcTx-1** (psalmotoxin 1) is a 40-amino acid peptide toxin derived from the venom of the Trinidad tarantula *Psalmopoeus cambridgei*. It is a member of the inhibitor cystine knot (ICK) peptide family, featuring three disulfide bonds stabilizing a compact structure comprised mainly of a three-stranded antiparallel β-sheet and multiple loops. PcTx-1 is the first identified and most potent **selective blocker** of the acid-sensing ion channel 1a (**ASIC1a**), a proton-gated sodium channel implicated in pain perception (nociception), synaptic plasticity, learning, and memory. PcTx-1 binds to the extracellular domain of ASIC1a, increasing its apparent affinity for protons and thereby inducing chronic desensitization at physiological pH. This mechanism effectively inhibits ASIC1a activity, with potential analgesic and neuroprotective effects shown in preclinical rodent models of acute pain and ischemic stroke. PcTx-1 blocks ASIC1a with high potency (IC50 in the low nanomolar range) and selectivity, and its unique binding surface provides a template for the development of future ASIC-targeted therapeutics[1][5][3][8][9].

Other names

psalmotoxin 1psalmotoxin1psalmotoxin-1π-TRTX-Pc1a