Spider venom-derived peptide induces hyperalgesia in Na<sub>v</sub>1.7 knockout mice by activating Na<sub>v</sub>1.9 channels.

Zhou, Xi; Ma, Tingbin; Yang, Luyao; Peng, Shuijiao; Li, Lulu; Wang, Zhouquan; Xiao, Zhen; Zhang, Qingfeng et al. · Nat Commun · 2020

basic_science · Level V

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Abstract

The sodium channels Na<sub>v</sub>1.7, Na<sub>v</sub>1.8 and Na<sub>v</sub>1.9 are critical for pain perception in peripheral nociceptors. Loss of function of Na<sub>v</sub>1.7 leads to congenital insensitivity to pain in humans. Here we show that the spider peptide toxin called HpTx1, first identified as an inhibitor of K<sub>v</sub>4.2, restores nociception in Na<sub>v</sub>1.7 knockout (Na<sub>v</sub>1.7-KO) mice by enhancing the excitability of dorsal root ganglion neurons. HpTx1 inhibits Na<sub>v</sub>1.7 and activates Na<sub>v</sub>1.9 but does not affect Na<sub>v</sub>1.8. This toxin produces pain in wild-type (WT) and Na<sub>v</sub>1.7-KO mice, and attenuates nociception in Na<sub>v</sub>1.9-KO mice, but has no effect in Na<sub>v</sub>1.8-KO mice. These data indicate that HpTx1-induced hypersensitivity is mediated by Na<sub>v</sub>1.9 activation and offers pharmacological insight into the relationship of the three Na<sub>v</sub> channels in pain signalling.

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