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本文研究了在2周左右的大鼠海马脑片上,突触前细胞内钙的释放和突触后对刺激mossy fiber传导通路的反应的相关性。用膜片钳全细胞电压钳的方法记录了海马CA3区的锥体细胞的兴奋性突触后电流。记录电极的电极内液含有较高浓度的BAPTA以中和细胞内升高的钙浓度。刺激电极放置在mossy fiber的传导通路上,分别给予20,50,100Hz的频率刺激。实验结果表明,在2周左右的大鼠海马脑片上,ryanodine在10和50μmol/L浓度时都降低了兴奋性突触后电流的幅度和曲线下面积。另一个药物cyclopiazonic acid(CPA)在30μmol/L浓度时降低了100Hz10个突触串刺激的兴奋性突触后电流的幅度和曲线下面积。用光学方法测量突触前细胞内钙离子水平的实验结果显示,在脑片灌流液中分别加入10和50μmol/L浓度的ryanodine以及30μmol/L浓度的CPA都能减小串刺激引起的细胞内钙的反应。电生理学和光学实验结果显示突触前细胞内钙的释放能够影响mossy fiber末端的神经介质的释放。
In this study, we investigated the relationship between calcium release from presynaptic cells and the response to post-synaptic stimulation of mossy fiber conduction in rat hippocampal slices at 2 weeks. The patch-clamp whole-cell voltage clamp method was used to record the excitatory postsynaptic currents of pyramidal cells in hippocampal CA3 region. The recording electrode electrode solution contains a higher concentration of BAPTA to neutralize elevated intracellular calcium concentration. Stimulation electrodes were placed in the mossy fiber conduction path, respectively, to give 20,50,100Hz frequency stimulation. The experimental results showed that ryanodine reduced the amplitude of excitatory postsynaptic currents and the area under the curve at both 10 and 50 μmol / L concentrations in rat hippocampal slices for about 2 weeks. Another drug, cyclopiazonic acid (CPA), decreased the amplitude and area under the curve of excitatory postsynaptic currents stimulated by 10 Hz synaptic clefts at 100 Hz at a concentration of 30 μmol / L. The experimental results of optical measurement of pre-synaptic calcium levels showed that the addition of 10 and 50 μmol / L ryanodine and 30 μmol / L CPA to the intracerebral perfusate decreased intracellular The reaction of calcium. Electrophysiological and optical experimental results show that pre-synaptic intracellular calcium release can affect neurotransmitter release at the mossy fiber end.