Quantal mechanism of long-term potentiation in hippocampal mossy-fiber synapses.
Quantal mechanism of long-term potentiation in hippocampal mossy-fiber synapses.
复制标题
海马苔藓纤维突触长时程增强的量子机制。
DOI：
10.1152/jn.1994.71.6.2552
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发表时间：
1994
影响因子：
2.5
通讯作者：
T. H. Brown
中科院分区：
文献类型：
--
作者：
Zixie Xiang;A. C. Greenwood;E. W. Kairiss;T. H. Brown
1.本文研究了大鼠海马苔藓纤维突触长时程增强（LTP）表达的量子机制。全细胞记录用于测量维持在31 +/-1 ℃的脑切片中LTP诱导前后的兴奋性突触后电流（EPSC）。2.从473个CA 3锥体神经元记录诱发的EPSC。每2-10 s重复一次成对脉冲（脉冲间间隔40 ms）刺激mf突触。在高频（100 Hz）mf刺激产生LTP表达之前和过程中获得至少400对mf反应。从五个神经元，表现出LTP，也满足严格的标准和程序，是必要的引发和确定单一的MF反应，得到足够的稳定数据。3.三个独立的证据暗示了突触前成分的机制基础MF LTP。第一个是基于经典方差法的图形版本。图形方差法（GV）的评价是通过在成对脉冲易化（PPF）过程中将细胞夹持在两个不同的保持电位。结果表明，GV方法可以区分大鼠mf突触平均量子含量m和平均量子大小q的变化。同样的分析，当应用于PPF之前和之后的LTP诱导，表明这两个结果从m的增加。4.第二条证据线是基于经典的失败方法。与mf LTP是由于m增加的推断一致，量子释放失败的数量在统计学上显著减少。（250字处删节）
1. The quantal mechanism underlying the expression of long-term potentiation (LTP) was studied in the mossy-fiber (mf) synapses of the rat hippocampus. Whole-cell recordings were used to measure the excitatory postsynaptic currents (EPSCs) before and after LTP induction in brain slices maintained at 31 +/- 1 degrees C. 2. Evoked EPSCs were recorded from 473 CA3 pyramidal neurons. The mf synapses were stimulated using paired pulses (40-ms interpulse interval) repeated every 2-10 s. At least 400 pairs of mf responses were obtained before and during the expression of LTP, which was produced by high-frequency (100 Hz) mf stimulation. Sufficiently stationary data were obtained from five neurons that exhibited LTP and that also satisfied strict criteria and procedures that are necessary for eliciting and identifying unitary mf responses. 3. Three independent lines of evidence implicated a presynaptic component to the mechanism underlying mf LTP. The first was based on a graphical version of the classical method of variance. The graphical variance (GV) method was evaluated by clamping the cell at two different holding potentials during paired-pulse facilitation (PPF). The results indicated that the GV method can distinguish changes in mean quantal content m and mean quantal size q in rat mf synapses. The same analysis, when applied to PPF before and after LTP induction, indicated that both result from an increase in m. 4. The second line of evidence was based on the classical method of failures. Consistent with the inference that mf LTP is due to an increase in m, there was a statistically significant reduction in the number of quantal release failures.(ABSTRACT TRUNCATED AT 250 WORDS)