Figure 2 Manipulation of actin filament dynamics does not impact the decrease in the ATP/ADP ratio or ATP level induced by blockade of ATP production in either growth cones or cell bodies.

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.

本研究将生长锥（growth cone）定义为轴突干远端10微米的区段。若生长锥带有片状伪足（lamellipodium），则以该片状伪足的最远端作为生长锥的最远端界定点；若未带有片状伪足，则以轴突干的最远端作为生长锥的最远端界定点。采用蔡司AxioVision软件对图像开展定量分析：首先勾勒出包含生长锥的感兴趣区域（region of interest），随后测定各相关成像通道的平均像素荧光强度以用于比值计算。在计算比值前，需先从生长锥感兴趣区域的平均荧光强度中，扣除图像中不含任何细胞的背景区域所得到的平均强度值。图像采集参数设置原则为使最大像素值处于动态范围的20%~30%区间，以此确保可检测到实验处理下荧光强度的升高与降低变化。