Bruns D, Riedel D, Klingauf J, Jahn R
Max-Planck Institute for Biophysical Chemistry, Department of Neurobiology, Göttingen, Germany.
Neuron. 2000 Oct;28(1):205-20. doi: 10.1016/s0896-6273(00)00097-0.
We have studied the origin of quantal variability for small synaptic vesicles (SSVs) and large dense-cored vesicles (LDCVs). As a model, we used serotonergic Retzius neurons of leech that allow for combined amperometrical and morphological analyses of quantal transmitter release. We find that the transmitter amount released by a SSV varies proportionally to the volume of the vesicle, suggesting that serotonin is stored at a constant intravesicular concentration and is completely discharged during exocytosis. Transmitter discharge from LDCVs shows a higher degree of variability than is expected from their size distribution, and bulk release from LDCVs is slower than release from SSVs. On average, differences in the transmitter amount released from SSVs and LDCVs are proportional to the size differences of the organelles, suggesting that transmitter is stored at similar concentrations in SSVs and LDCVs.
我们研究了小突触囊泡（SSV）和大致密核心囊泡（LDCV）量子变异性的起源。作为模型，我们使用了水蛭的5-羟色胺能Retzius神经元，其允许对量子递质释放进行安培法和形态学联合分析。我们发现，一个SSV释放的递质量与囊泡体积成比例变化，这表明5-羟色胺以恒定的囊泡内浓度储存，并在胞吐过程中完全释放。来自LDCV的递质释放显示出比根据其大小分布预期更高的变异性，并且LDCV的大量释放比SSV的释放更慢。平均而言，从SSV和LDCV释放的递质量差异与细胞器的大小差异成比例，这表明递质在SSV和LDCV中以相似的浓度储存。
