三丁基锡在鱼脑中的吸收与沿轴突传递的研究

The Study of Uptake of Tributyltin in the Fish Brain and Axonal Transport

为证实水中三丁基锡是否与Hg2+,Cd2+与Mn2+等离子相类似,即由鱼的感觉器官进入神经系统,再经过轴突传递进入大脑。笔者将一组虹鳟鱼暴露在含有113Sn-TBT(4 2kBq L)的水中;另一组经静脉注射113Sn-TBT。用全身放射自显影方式给出113Sn-TBT在鱼体中的分布。结果表明,113Sn-TBT可以通过鱼感觉器官,例如隆起颗粒进入鱼脑,并大量累积。静脉给药组的鱼大脑中也出现了放射性标记,表明TBT能通过血脑屏障到达大脑。由此得出结论:TBT可由水→鳃→血流→血脑屏障→大脑的传递过程在鱼的大脑中累积,但TBT也能经过水暴露敏感神经的端点被鱼体吸收,再由轴突传递直接输送到大脑。

It remains to be confirmed that waterborne tributyltin,similar to Hg^(2+),Cd^(2+) and Mn^(2+),can enter nerves innervating water-exposed sensory organs of fish and were transported to the brain by axonal transport.The authors exposed rainbow trout(Oncorhynchus mykiss)to waterborne ()^(113)Sn-TBT(4.2 kBq/L) with another group of fish received an intravenous injection of ()^(113)Sn-TBT.Distribution of ()^(113)Sn-TBT in the bodies of fish was visualized and quantified by quantitative whole-body autography.The results show that ()^(113)Sn-TBT can be taken up in different water-exposed sensory nerve terminals such as eminentia(lateral lines organs) and transported directly to the brain by axonal transport.Labeling of the brain was also seen for i.v.-injected fish,indicating that the blood-brain barrier is not impervious to TBT.It is concluded that TBT can be accumulated in fish brain by the transfer [water→gills→blood stream→blood-brain barrier→brain],and TBT can be taken up in the fish bodies through different water-exposed sensory nerve terminals and transported to the brain by axonal transport.