Graded synaptic transmission at the Caenorhabditis elegans neuromuscular junction
Graded synaptic transmission at the Caenorhabditis elegans neuromuscular junction
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DOI：
10.1073/pnas.0903570106
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发表时间：
2009-06-30
影响因子：
11.1
通讯作者：
Jorgensen, Erik M.
中科院分区：
文献类型：
--
作者：
Liu, Qiang;Hollopeter, Gunther;Jorgensen, Erik M.
大多数神经传递是由动作电位介导的，而感觉神经元被动地传播电信号并以分级方式释放神经递质。在这里，我们表明，秀丽隐杆线虫神经肌肉接头释放神经递质的分级方式。当运动神经元去极化光激活通道视紫红质-2，诱发的突触后电流与刺激的强度成比例。当运动神经元超极化光激活的盐视紫红质，紧张性释放的突触囊泡减少。这些数据表明，诱发和紧张性神经递质释放的分级响应膜电位。乙酰胆碱突触被高频刺激抑制，部分原因是尼古丁敏感的ACR-16受体的脱敏。相比之下，GABA突触在变得抑郁之前是促进的。分级传输和可塑性赋予这些突触广泛的动态范围。分级释放精确地传递刺激强度，甚至超极化输入。突触可塑性以使用依赖的方式改变进入肌肉的兴奋性和抑制性输入的平衡。
Most neurotransmission is mediated by action potentials, whereas sensory neurons propagate electrical signals passively and release neurotransmitter in a graded manner. Here, we demonstrate that Caenorhabditis elegans neuromuscular junctions release neurotransmitter in a graded fashion. When motor neurons were depolarized by light-activation of channelrhodopsin-2, the evoked postsynaptic current scaled with the strength of the stimulation. When motor neurons were hyperpolarized by light-activation of halorhodopsin, tonic release of synaptic vesicles was decreased. These data suggest that both evoked and tonic neurotransmitter release is graded in response to membrane potential. Acetylcholine synapses are depressed by high-frequency stimulation, in part due to desensitization of the nicotinesensitve ACR-16 receptor. By contrast, GABA synapses facilitate before becoming depressed. Graded transmission and plasticity confer a broad dynamic range to these synapses. Graded release precisely transmits stimulation intensity, even hyperpolarizing inputs. Synaptic plasticity alters the balance of excitatory and inhibitory inputs into the muscle in a use-dependent manner.