Evoked and spontaneous transmission favored by distinct sets of synapses.
Evoked and spontaneous transmission favored by distinct sets of synapses.
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DOI：
10.1016/j.cub.2014.01.022
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发表时间：
2014-03-03
期刊：
影响因子：
9.2
通讯作者：
Isacoff, Ehud Y.
中科院分区：
文献类型：
--
作者：
Peled, Einat S.;Newman, Zachary L.;Isacoff, Ehud Y.
自发的“微型”递质释放在所有突触上都以低速率发生。长期以来，自发释放被认为是一种不可避免的泄漏，最近被认为是由不同的突触前和突触后分子机制介导的，并在建立和调节神经元回路中发挥专门作用。目前尚不清楚自发和诱发的传输是如何在单个突触相关，它们是如何空间分布时，一个轴突与一个目标，以及它们是否共同调节多个接触。在果蝇幼虫神经肌肉接头的电生理记录，在使用依赖性谷氨酸受体（GluR）阻断剂Philanthotoxin的存在下，表明自发和诱发的传输采用不同的GluR集。在体内成像的传输使用突触靶向GCaMP3检测Ca2+内流通过GluRs揭示参与自发和诱发传输的突触之间的空间重叠很少。自发和诱发的传输与突触前水平的蛋白质Brp相反：高Brp的突触有利于诱发的传输，而低Brp的突触更活跃的自发。高频刺激并没有增加诱发和自发传递之间的重叠，而是降低了诱发传递中高度活跃的突触的自发释放率。虽然单个突触可以参与诱发和自发传递，但高度活跃的突触显示出对一种传递模式的偏好。突触前蛋白Brp促进诱发传递并抑制自发释放。这些发现表明存在突触前机制，促进突触特化，无论是诱发或自发传输。
Spontaneous “miniature” transmitter release takes place at low rates at all synapses. Long thought as an unavoidable leak, spontaneous release has recently been suggested to be mediated by distinct pre- and post-synaptic molecular machineries and to have a specialized role in setting up and adjusting neuronal circuits. It remains unclear how spontaneous and evoked transmission are related at individual synapses, how they are distributed spatially when an axon makes multiple contacts with a target and whether they are commonly regulated. Electrophysiological recordings in the Drosophila larval neuromuscular junction, in the presence of the use-dependent glutamate receptor (GluR) blocker Philanthotoxin, indicated that spontaneous and evoked transmission employ distinct sets of GluRs. In vivo imaging of transmission using synaptically-targeted GCaMP3 to detect Ca2+ influx through the GluRs revealed little spatial overlap between synapses participating in spontaneous and evoked transmission. Spontaneous and evoked transmission were oppositely correlated with presynaptic levels of the protein Brp: synapses with high Brp favored evoked transmission, whereas synapses with low Brp were more active spontaneously. High frequency stimulation did not increase the overlap between evoked and spontaneous transmission, and instead decreased the rate of spontaneous release from synapses that were highly active in evoked transmission. While individual synapses can participate in both evoked and spontaneous transmission, highly-active synapses show a preference for one mode of transmission. The presynaptic protein Brp promotes evoked transmission and suppresses spontaneous release. These findings suggest the existence of presynaptic mechanisms that promote synaptic specialization to either evoked or spontaneous transmission.
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影响因子：
5.7
作者：
Ramirez DM;Kavalali ET
通讯作者：
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影响因子：
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作者：
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DOI：
10.1016/0742-8413(91)90236-m
发表时间：
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影响因子：
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作者：
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作者：
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