The effects of temperature on vesicular supply and release in autaptic cultures of rat and mouse hippocampal neurons
The effects of temperature on vesicular supply and release in autaptic cultures of rat and mouse hippocampal neurons
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DOI：
10.1113/jphysiol.2001.013277
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发表时间：
2002-03-01
影响因子：
5.5
通讯作者：
Rosenmund, C
中科院分区：
文献类型：
--
作者：
Pyott, SJ;Rosenmund, C
膜融合在突触小泡循环中起着核心作用。虽然许多融合前和融合后事件都在室温下进行了研究，但很少有研究人员在更生理相关的温度下研究这些过程。我们使用海马神经元的自体培养物来研究温度从 25 摄氏度升高到 35 摄氏度所带来的突触小泡易释放池 (RRP) 的大小和再填充率的变化。我们还检查了自发释放和动作电位 (AP) 诱发释放的温度依赖性变化，以及 AP 期间释放的 RRP 比例。尽管我们发现在较高温度下 RRP 的补充率增加了三倍，但 RRP 的尺寸并没有随着温度的升高而发生明显变化。此外，我们观察到 AP 期间释放的量子略有但显着减少。这种增加的再填充率和降低的释放概率导致在较高温度下的高频刺激期间突触抑制的程度和时间过程减少。突触抑制的减少伴随着高频刺激期间释放的同步成分的维持的增加。这些发现表明，室温下海马神经元的囊泡供应和释放动态在接近生理温度时显着不同，并且可能影响我们目前对单个神经元和神经元网络处理信息方式的理解。
Membrane fusion plays a central role in the synaptic vesicle cycle. While many of the pre- and post-fusion events have been investigated at room temperature, few researchers have investigated these processes at more physiologically relevant temperatures. We have used autaptic cultures of hippocampal neurons to investigate changes in the size and refilling rate of the readily releasable pool (RRP) of synaptic vesicles brought about by an increase in temperature from 25 to 35 degreesC. We have also examined temperature-dependent changes in spontaneous and action potential (AP)evoked release as well as the fraction of the RRP that is released during an AP. Although we found a threefold increase in the refilling rate of the RRP at the higher temperature, there was no apparent change in the size of the RRP with increased temperature. Moreover, we observed a slight but significant decrease in the quanta released during an AP. This increased refilling rate and decreased release probability resulted in a reduction of both the degree and time course of synaptic depression during high frequency stimulation at the higher temperature. This reduction in synaptic depression was accompanied by an increased maintenance of the synchronous component of release during high frequency stimulation. These findings indicate that the dynamics of vesicular supply and release in hippocampal neurons at room temperature are significantly different at near physiological temperatures and could affect our present understanding of the way in which individual neurons and networks of neurons process information.