This family includes peptides isolated from Phoneutria such as delta-ctenitoxins. Members of the CNTX-Pn1a family and its paralogs (delta-CNTX-Pn1b through delta-CNTX-Pn1e) of Phoneutria toxins have complex effects on sodium channels but their primary effect appears to be an inhibition of channel inactivation, a pharmacology similar to that of the delta-atracotoxins and delta-conotoxins. Orthologous toxins such as delta-CNTX-Pr1/PK1 and Pn2 are also family members, some of which act by blocking the calcium channels [1]. Delta-CNTX-Pn1a and delta-CNTX-PN2a are 48-amino-acid polypeptides, with 5 disulfide bridges [2]. The later has a complex pharmacology that results in inhibition of NaV channel inactivation and a hyperpolarizing shift in the channel activation potential [3].

1: A rational nomenclature for naming peptide toxins from spiders and other venomous animals. King GF, Gentz MC, Escoubas P, Nicholson GM; Toxicon. 2008;52:264-276. PMID:18619481

2: delta-Ctenitoxin-Pn1a, a Peptide from Phoneutria nigriventer Spider Venom, Shows Antinociceptive Effect Involving Opioid and Cannabinoid Systems, in Rats. Emerich BL, Ferreira RC, Cordeiro MN, Borges MH, Pimenta AM, Figueiredo SG, Duarte ID, de Lima ME; Toxins (Basel). 2016;8:106. PMID:27077886

3: Spider-venom peptides as therapeutics. Saez NJ, Senff S, Jensen JE, Er SY, Herzig V, Rash LD, King GF; Toxins (Basel). 2010;2:2851-2871. PMID:22069579