Poneratoxin （PoTX） is an insect neuropeptide isolated from ant venom. It was previously demonstrated that administration of synthetic PoTX into the lateral brain ventricle （icv） induced in rats significant antinoc...Poneratoxin （PoTX） is an insect neuropeptide isolated from ant venom. It was previously demonstrated that administration of synthetic PoTX into the lateral brain ventricle （icv） induced in rats significant antinociceptive effect. Moreover it was demonstrated that this effect was not mediated by opioid receptors. The aim of present study was to determine other probable mechanisms mediating antinociceptive effect of PoTX, above all： （1） to check if insect-derived pentapeptide Any-GS may influence on PoTX-induced analgesia in rats, and （2） to estimate the role of voltage-gated sodium channels in rat＇s brain in antinociceptive effect of PoTX. The study was performed on adult, female wistar rats, which a week before experiments were implanted with polyethylene cannulas into the lateral brain ventricle （icv）. Antinociceptive effect of PoTX applied directly icv was determined in rats by the test of the tail immersion. PoTX applied icv at the dose of 1 or 5 nmol induced significant antinociceptive effect in rats. Pretreatment rats with equimolar dose of 1 or 5 nmol of veratridine, an agent, which opens voltage-gated sodium channels in neurons of rat brain, did not modify effect of PoTX. On the other hand, prior icv administration of pentapeptide Any-GS significantly inhibited antinociceptive effect of both icv doses of 1 and 5 nmols of PoTX. The results of the present study demonstrated antagonistic effect Any-GS against PoTX-induced analgesia. Thus blocking effect Any-GS on PoTX-induced analgesia indicates that this insect peptide is a probable antagonist of PoTX.展开更多
文摘Poneratoxin （PoTX） is an insect neuropeptide isolated from ant venom. It was previously demonstrated that administration of synthetic PoTX into the lateral brain ventricle （icv） induced in rats significant antinociceptive effect. Moreover it was demonstrated that this effect was not mediated by opioid receptors. The aim of present study was to determine other probable mechanisms mediating antinociceptive effect of PoTX, above all： （1） to check if insect-derived pentapeptide Any-GS may influence on PoTX-induced analgesia in rats, and （2） to estimate the role of voltage-gated sodium channels in rat＇s brain in antinociceptive effect of PoTX. The study was performed on adult, female wistar rats, which a week before experiments were implanted with polyethylene cannulas into the lateral brain ventricle （icv）. Antinociceptive effect of PoTX applied directly icv was determined in rats by the test of the tail immersion. PoTX applied icv at the dose of 1 or 5 nmol induced significant antinociceptive effect in rats. Pretreatment rats with equimolar dose of 1 or 5 nmol of veratridine, an agent, which opens voltage-gated sodium channels in neurons of rat brain, did not modify effect of PoTX. On the other hand, prior icv administration of pentapeptide Any-GS significantly inhibited antinociceptive effect of both icv doses of 1 and 5 nmols of PoTX. The results of the present study demonstrated antagonistic effect Any-GS against PoTX-induced analgesia. Thus blocking effect Any-GS on PoTX-induced analgesia indicates that this insect peptide is a probable antagonist of PoTX.
