Dendritic spines are the primary site of excitatory synaptic input onto neurons, and are biochemically isolated from the parent dendritic shaft by their thin neck. However, due to the lack of direct electrical recordings from spines, the influence that the neck resistance has on synaptic transmission, and the extent to which spines compartmentalize voltage, specifically excitatory postsynaptic potentials, albeit critical, remains controversial. Here, we use quantum-dot-coated nanopipette electrodes (tip diameters ∼15–30 nm) to establish the first intracellular recordings from targeted spine heads under two-photon visualization. Using simultaneous somato-spine electrical recordings, we find that back propagating action potentials fully invade spines, that excitatory postsynaptic potentials are large in the spine head (mean 26 mV) but are strongly attenuated at the soma (0.5–1 mV) and that the estimated neck resistance (mean 420 MΩ) is large enough to generate significant voltage compartmentalization. Nanopipettes can thus be used to electrically probe biological nanostructures.

树突棘是神经元兴奋性突触输入的主要部位，并通过其细颈与母体树突干生化分离。但是，由于缺乏来自棘突的直接电记录，因此颈部电阻对突触传递的影响以及棘突分隔电压的程度（特别是兴奋性突触后突触电位，尽管很关键）的程度仍然存在争议。在这里，我们使用量子点涂覆的纳米吸管电极（尖端直径〜15–30 nm）在双光子显像下从目标脊柱头部建立第一个细胞内记录。使用同时进行的躯体-脊柱电记录，我们发现向后传播的动作电位完全侵入棘突，脊柱头部的兴奋性突触后电位很大（平均26 mV），但在躯体上被强烈衰减（0.5-1 mV），并且估计的颈部电阻（平均420MΩ）足够大，可以产生明显的电压分隔。纳米移液器因此可以用于电探测生物纳米结构。