Identification and purification of an irreversible presynaptic neurotoxin from the venom of the spider Hololena curta.
Identification and purification of an irreversible presynaptic neurotoxin from the venom of the spider Hololena curta.
复制标题
从蜘蛛 Hololena curta 的毒液中鉴定和纯化不可逆的突触前神经毒素。
DOI：
10.1073/pnas.84.10.3506
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发表时间：
1987
影响因子：
11.1
通讯作者：
Jan,LY
中科院分区：
文献类型：
--
作者：
Bowers,CW;Phillips,HS;Lee,P;Jan,YN;Jan,LY
在果蝇中寻找抑制神经元钙通道的强效毒素，导致从狩猎蜘蛛Hololena curta的毒液中鉴定出突触前神经毒素。使用果蝇神经肌肉接头作为测定，突触前抑制活性纯化使用凝胶过滤和反相HPLC。凝胶电泳数据表明，该毒素是由两个不同的亚基的Mr 7000和9000。在纳摩尔浓度的毒素产生了一个完整的和持久的抑制突触传递在果蝇幼虫神经肌肉接头，而不影响自发发生的微型接头电位的幅度。甚至在运动神经末梢的直接去极化期间也观察到毒素产生的传递阻断。这些生理学结果表明，末端是毒素的作用部位。使用异常兴奋的果蝇突变体的间接证据表明，毒素是通过改变神经末梢的电特性而不是通过干扰钙离子内流后可能发生的非电事件来抑制递质释放的。Hololena毒素的所有作用都可以通过对果蝇运动神经元突触前钙通道的特异性和直接作用来解释。
A search for potent toxins that inhibit neuronal calcium channels in Drosophila melanogaster has resulted in the identification of a presynaptic neurotoxin from the venom of the hunting spider Hololena curta. Using Drosophila neuromuscular junction as an assay, presynaptic inhibitory activity was purified using gel filtration and reverse-phase HPLC. Data from gel electrophoresis indicate that the toxin is composed of two different subunits of Mr 7000 and 9000. At nanomolar concentrations the toxin produced a complete and long-lasting inhibition of synaptic transmission at the Drosophila larval neuromuscular junction without affecting the amplitudes of the spontaneously occurring miniature junction potentials. The block of transmission produced by the toxin was observed even during the direct depolarization of the motor nerve terminal. These physiological results indicate that the terminal is the site of action for the toxin. Indirect evidence using abnormally excitable Drosophila mutants suggests that the toxin is inhibiting transmitter release by altering the electrical properties of the nerve terminal rather than by interfering with nonelectrical events that may occur subsequent to calcium influx. All of the actions of the Hololena toxin can be explained by a specific and direct effect on presynaptic calcium channels in Drosophila motor neurons.