Antinociceptive effect of poneratoxin [PoTX] in rats

Poneratoxin (molecular weight 2932) is a 25 amino acid neuropeptide, isolated from an ant venom. It affects excitability of nerve and muscle fibres by changing the kinetics of the voltage-dependent sodium channel. The aim of the study was to investigate the analgetic effect of synthetic poneratoxin (PoTX) in adult female Wistar rats. In the first part of the study the animals received PoTX intracerebroventricularly. The analgetic effect was evaluated by a tail immersion test. In the second part of the experiment the analgetic effect of PoTX was blocked with naloxone, an opioid receptors antagonist. The study showed that poneratoxin exerts the analgetic effect in rats and this effect is not mediated by central opioid system. Therefore it was concluded that other mechanism is resposible for the effect of PoTX.