Svoboda K, Tank D W, Denk W
Biological Computation Research Department, Bell Laboratories, Lucent Technologies, Murray Hill, NJ 07974, USA.
Science. 1996 May 3;272(5262):716-9. doi: 10.1126/science.272.5262.716.
Characterization of the diffusional and electrotonic coupling of spines to the dendritic shaft is crucial to understanding neuronal integration and synaptic plasticity. Two-photon photobleaching and photorelease of fluorescein dextran were used to generate concentration gradients between spines and shafts in rat CA1 pyramidal neurons. Diffusional reequilibration was monitored with two-photon fluorescence imaging. The time course of reequilibration was exponential, with time constants in the range of 20 to 100 milliseconds, demonstrating chemical compartmentalization on such time scales. These values imply that electrical spine neck resistances are unlikely to exceed 150 megohms and more likely range from 4 to 50 megohms.
对棘突与树突干之间的扩散耦合和电紧张耦合进行表征，对于理解神经元整合和突触可塑性至关重要。利用双光子光漂白和荧光素葡聚糖的光释放，在大鼠CA1锥体神经元的棘突和树突干之间产生浓度梯度。通过双光子荧光成像监测扩散再平衡。再平衡的时间进程呈指数形式，时间常数在20至100毫秒范围内，表明在这样的时间尺度上存在化学分隔。这些数值意味着棘突颈部电阻不太可能超过150兆欧，更可能在4至50兆欧范围内。
