Segal J R, Ceccarelli B, Fesce R, Hurlbut W P
Biophys J. 1985 Feb;47(2 Pt 1):183-202. doi: 10.1016/s0006-3495(85)83891-1.
A method based upon an extension of Campbell's theorem is used to measure the amplitude, waveform, and frequency of occurrence of miniature endplate potentials (mepps) at rapidly secreting neuromuscular junctions of frog cutaneous pectoris muscles. Measurements of the variance, skew, and power spectrum of the fluctuations in membrane potential are used to deduce the mepp parameters. These estimates of mepp amplitude and frequency are insensitive to slow drifts in membrane potential that preclude the conventional application of Campbell's theorem, which uses the mean and variance. The new method becomes unreliable at high mepp frequencies because the distribution of the values of membrane potential approaches a Gaussian thereby reducing the accuracy of skew measurements. Frequencies approaching 10(4) s-1 can be measured, however, if the data are high-pass filtered. The method has been tested with computer simulated data and applied to junctions exposed to La3+; the effects of Ca2+ on the La3+-induced secretion have been explored. Some muscles were fixed after treatment with La3+, and changes in nerve terminal ultrastructure were assessed by morphometric analysis of electron micrographs. Horseradish peroxidase was used to obtain information about vesicle recycling.
一种基于坎贝尔定理扩展的方法被用于测量蛙胸皮肌快速分泌神经肌肉接头处微小终板电位（mepps）的幅度、波形和出现频率。通过测量膜电位波动的方差、偏度和功率谱来推导mepp参数。这些对mepp幅度和频率的估计对膜电位的缓慢漂移不敏感，而这种缓慢漂移会妨碍使用均值和方差的传统坎贝尔定理的应用。在高mepp频率下，新方法变得不可靠，因为膜电位值的分布接近高斯分布，从而降低了偏度测量的准确性。然而，如果对数据进行高通滤波，则可以测量接近10(4) s-1的频率。该方法已通过计算机模拟数据进行测试，并应用于暴露于La3+的接头；探讨了Ca2+对La3+诱导分泌的影响。一些肌肉在La3+处理后固定，通过电子显微镜图像的形态计量分析评估神经末梢超微结构的变化。使用辣根过氧化物酶来获取有关囊泡循环的信息。
