EPSPs Measured in Proximal Dendritic Spines of Cortical Pyramidal Neurons.
EPSPs Measured in Proximal Dendritic Spines of Cortical Pyramidal Neurons.
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DOI：
10.1523/eneuro.0050-15.2016
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发表时间：
2016-03
期刊：
影响因子：
3.4
通讯作者：
Loew LM
中科院分区：
文献类型：
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作者：
Acker CD;Hoyos E;Loew LM
当神经递质谷氨酸与突触后受体结合时，就会发生EPSP，这些受体位于称为树突棘的多形膜上。为了传递突触信号，这些电位必须通过脊椎颈部和树突树到达胞体。由于它们的体积很小，脊椎的电学行为和它们划分电信号的能力一直很难在实验上评估。在这项研究中，我们发展了一种同时进行双光子电压敏感染料记录和双光子谷氨酸去化的方法，以测量CD1对照组小鼠急性脑片L5锥体神经元基树突上单棘未老化诱发的EPSP的特征(幅度和持续时间)。我们能够从广泛的脊柱形态中记录到类似于SOMA的微型EPSPS的未老化诱发脊椎电位。在近端脊髓，这些电位平均为13.0 mV(范围6.5-30.8 mV；N=20)，体细胞EPSP平均为0.59 mV，而平均衰减比(脊柱/胞体)为25.3。脊髓EPSP波群持续时间平均为11.7ms。模拟研究表明，颈椎阻力(RNACK)在脊柱EPSP波幅中起着重要作用。用于通过与电压敏感染料测量拟合来估计RNeck的模拟产生了179MΩ的平均值(范围23-420MΩ；N=19)。基于光漂白后细胞浆染料的荧光恢复的独立测量产生了204MΩ的平均RNeck估计(范围52-521MΩ；N=34)。
EPSPs occur when the neurotransmitter glutamate binds to postsynaptic receptors located on small pleomorphic membrane protrusions called dendritic spines. To transmit the synaptic signal, these potentials must travel through the spine neck and the dendritic tree to reach the soma. Due to their small size, the electrical behavior of spines and their ability to compartmentalize electrical signals has been very difficult to assess experimentally. In this study, we developed a method to perform simultaneous two-photon voltage-sensitive dye recording with two-photon glutamate uncaging in order to measure the characteristics (amplitude and duration) of uncaging-evoked EPSPs in single spines on the basal dendrites of L5 pyramidal neurons in acute brain slices from CD1 control mice. We were able to record uncaging-evoked spine potentials that resembled miniature EPSPs at the soma from a wide range of spine morphologies. In proximal spines, these potentials averaged 13.0 mV (range, 6.5–30.8 mV; N = 20) for an average somatic EPSP of 0.59 mV, whereas the mean attenuation ratio (spine/soma) was found to be 25.3. Durations of spine EPSP waveforms were found to be 11.7 ms on average. Modeling studies demonstrate the important role that spine neck resistance (Rneck) plays in spine EPSP amplitudes. Simulations used to estimate Rneck by fits to voltage-sensitive dye measurements produced a mean of 179 MΩ (range, 23–420 MΩ; N = 19). Independent measurements based on fluorescence recovery after photobleaching of a cytosolic dye from spines of the same population of neurons produced a mean Rneck estimate of 204 MΩ (range, 52–521 MΩ; N = 34).