Stevens C F, Wang Y
Howard Hughes Medical Institute, Salk Institute Molecular Neurobiology Laboratory, La Jolla, California 92037, USA.
Neuron. 1995 Apr;14(4):795-802. doi: 10.1016/0896-6273(95)90223-6.
Using whole-cell recording from CA1 hippocampal pyramidal neurons and minimal stimulation of Schaffer collaterals, we have studied what seem to be single synapses. Although the transmission at a putative single synapses is quite unreliable, the synapse can be made to release transmitter reliably in response to the second stimulus in a pair of stimuli that re presented in rapid succession (e.g., 50 ms separation). Statistical analysis of transsmision failures seen with such paired pulse stimulation reveals that the majority of stimulus-evoked synaptic currents (> 90%) are produced by a single synapse under the conditions of minimal stimulation, even if multiple synapses are actually present. Individual synapses appear to release either zero or one quantum; that is, a single synapse seems to have only one functional release sit at any time. After the release site has been used, approximately 20 ms is required to refill the site so that it can be used again.
利用从CA1海马锥体神经元进行的全细胞记录以及对谢弗侧支的最小刺激，我们研究了看似单个的突触。尽管在假定的单个突触处的传递相当不可靠，但该突触可以被诱导在快速连续呈现的一对刺激中的第二个刺激（例如，间隔50毫秒）时可靠地释放递质。对这种配对脉冲刺激所观察到的传递失败进行统计分析表明，在最小刺激条件下，即使实际存在多个突触，大多数刺激诱发的突触电流（>90%）也是由单个突触产生的。单个突触似乎要么释放零个量子，要么释放一个量子；也就是说，单个突触在任何时候似乎只有一个功能性释放位点。在释放位点被使用后，大约需要20毫秒来重新填充该位点，以便它可以再次被使用。
