Kolesnyk O P, Fedulova S A, Veselovsky N S
Fiziol Zh (1994). 2016;62(5):12-18.
Changes in amplitudes of evoked inhibitory postsynaptic currents (eIPSCs) from rat cultured hippocampal neurons were studied using whole-cell patch-clamp technique in postsynaptic neuron and local extracellular electrical paired pulse stimulation of single presynaptic axon. Paired pulse depression (PPD) and paired pulse facilitation (PPF) were observed in studied 43 neurons. According to coefficient of variance (CV) analysis was found that CV of second respond was significantly larger than CV first by 57 % (n 26) during depression and significanty smaller by 27 % (n = 17) during facilitation. Thus, only presynaptic mechanism underlies short-term depression and facilitation. We also estimated quantal parameters assuming that transmitter release is reasonably described by a binomial distribution. We found that under our experimental conditions there were no significant changes in GABA release probability during PPD and PPF. The values of mean quantal content and mean number of sites of transmitter release were the same for first stimulus in pair and were equal 9.7 in depression and 5 in facilitation of synaptic transmission. The values both of them for second stimulus were significant decreased by 28 and 26% during PPD and were significant increased by 14 and 11% during PPF, respectively. Thus, there is significant difference in quantal parameters characterizing GABA release during short-term depression and facilitation of synaptic transmission.
采用全细胞膜片钳技术，在突触后神经元中记录大鼠培养海马神经元诱发抑制性突触后电流（eIPSCs）的幅度变化，并对单个突触前轴突进行局部细胞外电刺激配对脉冲刺激。在所研究的43个神经元中观察到了配对脉冲抑制（PPD）和配对脉冲易化（PPF）。根据变异系数（CV）分析发现，在抑制期间，第二个反应的CV比第一个反应的CV显著大57%（n = 26），而在易化期间则显著小27%（n = 17）。因此，短期抑制和易化仅由突触前机制介导。我们还假设递质释放可用二项分布合理描述，估计了量子参数。我们发现，在我们的实验条件下，PPD和PPF期间GABA释放概率没有显著变化。配对刺激中第一个刺激的平均量子含量和递质释放位点的平均数在抑制突触传递时为9.7，在易化突触传递时为5。在PPD期间，第二个刺激的这两个值均显著降低28%，在PPF期间则分别显著增加14%和11%。因此，在突触传递的短期抑制和易化过程中，表征GABA释放的量子参数存在显著差异。
