PnAn13, an antinociceptive synthetic peptide inspired in the toxin PnTx4(6-1) (δ-Ctenitoxin-Pn1a).

Animal venoms are an almost inexhaustible source for promising molecules with biological activity and the venom of spider is a good example of this. Among several other toxins obtained from this venom, PnTx4(6-1), also called δ-Ctenitoxin-Pn1a, was isolated and initially described as an insect toxin that binds to the site 3 of sodium channels in cockroach nerve cord synaptosomes () and slows down sodium current inactivation in isolated axons of this animal. This toxin did not cause any apparent toxicity to mice when intracerebroventricularly injected (30 μg).

δ-Ctenitoxin-Pn1a, a Peptide from Phoneutria nigriventer Spider Venom, Shows Antinociceptive Effect Involving Opioid and Cannabinoid Systems, in Rats.

PnTx4(6-1), henceforth renamed δ-Ctenitoxin-Pn1a (δ-CNTX-Pn1a), a peptide from Phoneutria nigriventer spider venom, initially described as an insect toxin, binds to site 3 of sodium channels in nerve cord synaptosomes and slows down sodium current inactivation in isolated axons in cockroaches (Periplaneta americana). δ-CNTX-Pn1a does not cause any apparent toxicity to mice, when intracerebroventricularly injected (30 μg). In this study, we evaluated the antinociceptive effect of δ-CNTX-Pn1a in three animal pain models and investigated its mechanism of action in acute pain.