Presynaptic long-term facilitation at the crayfish neuromuscular junction: voltage-dependent and ion-dependent phases
Presynaptic long-term facilitation at the crayfish neuromuscular junction: voltage-dependent and ion-dependent phases
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小龙虾神经肌肉接头的突触前长期促进：电压依赖性和离子依赖性阶段
DOI：
10.1523/jneurosci.08-12-04667.1988
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发表时间：
1988
影响因子：
--
通讯作者：
H. Atwood
中科院分区：
文献类型：
--
作者：
J. Wojtowicz;H. Atwood
研究了小龙虾开瓶肌突触传递的长期促进（LTF），以确定其诱导和表达的必要因素。在无动作电位的情况下，通过突触前神经末梢细胞内去极化诱导LTF。诱导后，突触传递在数小时内增强约80%。突触前和突触后细胞的细胞内记录，结合离子和药理学试验，允许将LTF分解为两个阶段：最初的强直性阶段取决于钠和钙离子的存在，以及随后的持久期。后一种突触传递的持久增强是由突触末端的反复去极化引起的，但不依赖于钠离子或钙离子的流入或钙离子的细胞内释放。LTF的强直期和长时期均可归因于单个神经元的活动，即它们是同突触现象。此外，LTF与量子释放的增加有关，而量子的大小保持不变。在LTF持久期，神经末梢释放的递质比LTF诱导前更多。因此，LTF位点位于突触前。我们的研究结果表明突触前膜中存在电压依赖机制，不同于Na或Ca通道的电压门控。这种机制在小龙虾神经肌肉连接处和其他神经系统中建立持久的突触变化可能是重要的。
Long-term facilitation (LTF) of synaptic transmission was investigated in the crayfish opener muscle to determine the factors necessary for its induction and expression. LTF was induced without action potentials by intracellular depolarization of presynaptic nerve terminals. Following induction, the synaptic transmission was enhanced by about 80% for a period of several hours. Intracellular recordings from pre- and postsynaptic cells, combined with ionic and pharmacological tests, permitted dissection of LTF into 2 phases: an initial tetanic phase that depended on the presence of both sodium and calcium ions and a subsequent long-lasting phase. This latter long-lasting enhancement of synaptic transmission was induced by repeated depolarizations of synaptic terminals but did not depend on the influx of sodium or calcium ions or on intracellular release of calcium ions. Both tetanic and long-lasting phases of LTF are attributable to activity of a single neuron, i.e., they are homosynaptic phenomena. Furthermore, LTF is associated with an increase of quantal release, whereas the size of quanta remains unchanged. During the long-lasting phase of LTF, the nerve terminal releases more transmitter for a given depolarization than before induction of LTF. Thus, the locus of LTF is presynaptic. Our findings suggest the presence of a voltage-dependent mechanism in the presynaptic membrane different from voltage-gating of Na or Ca channels. Such a mechanism may be important in the establishment of long-lasting synaptic changes at the crayfish neuromuscular junction and perhaps in other neural systems.
DOI：
10.1126/science.2868525
发表时间：
1986
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Zucker,RS;Landò,L
通讯作者：
Landò,L