von Gersdorff H, Matthews G
Max Planck Institute for Biophysical Chemistry, Department of Membrane Biophysics, Göttingen, Germany.
Annu Rev Physiol. 1999;61:725-52. doi: 10.1146/annurev.physiol.61.1.725.
Patch-clamp capacitance measurements can monitor in real time the kinetics of exocytosis and endocytosis in living cells. We review the application of this technique to the giant presynaptic terminals of goldfish bipolar cells. These terminals secrete glutamate via the fusion of small, clear-core vesicles at specialized, active zones of release called synaptic ribbons. We compare the functional characteristics of transmitter release at ribbon-type and conventional synapses, both of which have a unique capacity for fast and focal vesicle fusion. Subsequent rapid retrieval and recycling of fused synaptic vesicle membrane allow presynaptic terminals to function independently of the cell soma and, thus, as autonomous computational units. Together with the mobilization of reserve vesicle pools, local cycling of synaptic vesicles may delay the onset of vesicle pool depletion and sustain neuronal output during high stimulation frequencies.
膜片钳电容测量可以实时监测活细胞中胞吐作用和胞吞作用的动力学。我们回顾了这项技术在金鱼双极细胞巨大突触前终末中的应用。这些终末通过小而清亮核心囊泡在称为突触带的特化释放活性区融合来分泌谷氨酸。我们比较了带状突触和传统突触处递质释放的功能特性，二者都具有快速且局部囊泡融合的独特能力。融合的突触囊泡膜随后的快速回收和再循环使突触前终末能够独立于细胞体发挥作用，从而作为自主计算单元。与储备囊泡池的动员一起，突触囊泡的局部循环可能会延迟囊泡池耗竭的开始，并在高刺激频率下维持神经元输出。
