Figure 8. Suppression of microtubule plus tip dynamic instability blocks actin filament dependent growth cone elaboration in response to acute NGF treatment but does not alter the ATP/ADP ratio.

The growth cone was defined as the distal 10 microns of the axon shaft. If a growth cone exhibited lamellipodia then the distal most extent of the lamellipodium was taken as the distal most point on the growth cone, if not the distal most extent of the axon shaft was used as the defining distal point. Quantitative analysis of images was performed using Zeiss AxioVision software. The region of interest encompassing the growth cone was outlined and measurements of mean pixel fluorescence intensity in all relevant channels was determined for generation of ratios. For each channel, the mean intensity value obtained from the background of the image not containing any cells was subtracted from the mean intensity in the growth cone region of interest prior to determination of the ratio. Acquisition settings were chosen to generate maximum pixel values between 20-30% of the dynamic range to allow for detection of both decreases and increases in intensity in response to experimental treatments.

生长锥（growth cone）被定义为轴突干（axon shaft）的远端10微米区段。若生长锥带有板状伪足（lamellipodia），则以该板状伪足的最远端作为生长锥的最远端点；若不存在板状伪足，则以轴突干的最远端作为界定的最远端点。采用蔡司AxioVision软件完成图像的定量分析。勾勒出包含生长锥的感兴趣区域（region of interest），并测定所有相关通道内的平均像素荧光强度以生成强度比值。针对每个通道，在计算强度比值前，需先从生长锥感兴趣区域的平均荧光强度中，减去取自图像中不含任何细胞区域的背景平均强度值。采集参数设置为使最大像素值处于动态范围的20%至30%区间，以便能够检测到实验处理下荧光强度的升高与降低变化。