Origin of tetrodotoxin and toxification mechanism in tetrodotoxin-bearing pufferfishes and Japanese newt

点击翻译按钮获取中文摘要

High molecular weight substances (TTX-binding substances) which had ability to bind tetrodotoxin (TTX) were proved to be contained in the blood plasma of puffer fishes. Most of TTX in the plasma existed in a state of binding with the subsances. The TTX-binding substances had ability to bind not only TTX but also saxitoxin (STX). Small amount of STX bound with the substances existed naturally in the plasma. All the plasma of puffer fishes examined showed TTX-binding ability. In them the plasma of finepatterned puffer, Takifugu poecilonotus, showed the strongest activity, its one mililiter plasma could bind 23 mouse units of TTX.The TTX-binding substances unbound TTX under acidic condition and bound under neutral condition reversibly. The TTX-binding substances bound STX rather than TTX but did not bind goniotoxins. The TTX-binding substances were examined for neutralizing effects against the lethal activity of TTX or STX.When the mixture of the TTX-binding substances and TTX or STX was injected i.p. into mice, the lethal activity of TTX or STX was significantly reduced.Japanese newt is one of TTX-bearing animals. Specimens were collected from several spots at different vertical levels in Sanriku town, Iwate prefecture. The specimens were assayd for toxicity by mouse assay. A wide individual variation of toxicity was recognized among the specimens caught from a given spot. The local variation in toxicity was also large. There was a tendency that the toxicity was higher in specimens collected at high elevation than at low elevation. Toxicity of the newts collected from rice fields near seashore was increased 100 days after transportation them from the rice fields to a marsh near the top of a mountain.