Department of Electrical and Electronical Engineering, Public University of Navarra, 31006 Pamplona, Spain.
Clin Neurophysiol. 2010 Feb;121(2):214-20. doi: 10.1016/j.clinph.2009.10.006. Epub 2009 Dec 1.
This study aims to check the theoretical predictions of the small changes in the rise-time of human single muscle fibre action potentials (SFAPs) experimentally when the recording electrode is in the proximity of the fibre.
Using a single-fibre electrode, 93 sets of consecutive SFAPs were recorded under needle movement from the m. tibialis anterior of four normal subjects. In each SFAP set, the excitation source was assumed to remain unchanged and thus only the fibre-electrode distance varied between consecutive discharges. The changes of SFAP rise-time with peak-to-peak amplitude (V(pp)) within each SFAP set were used to study the relationship between rise-time and radial distance.
SFAP rise-time was relatively unchanged when V(pp) was greater than 1.0-1.5 mV. For V(pp) smaller than 1.0-1.5 mV, the sensitivity of rise-time to changes in radial distance increased considerably.
Although the SFAP rise-time is practically not influenced by changes in radial distance in the proximity of muscle fibres, future work is necessary to confirm the hypothesis of using the rise-time for estimating changes in the intracellular action potential (IAP) depolarisation phase.
The studies are useful in diagnostics and following the results of treatment in patients suffering from muscular dystrophy or myopathy, they are known to be accompanied by severe changes in the duration of IAP.
本研究旨在通过实验检查当记录电极接近纤维时，人单肌纤维动作电位 (SFAP) 上升时间的微小变化的理论预测。
使用单纤维电极，从四名正常受试者的胫骨前肌中记录了 93 组连续的 SFAP。在每组 SFAP 中，假设激发源保持不变，因此仅在连续放电之间改变纤维-电极距离。在每组 SFAP 内，用 SFAP 上升时间与峰峰值幅度 (V(pp)) 的变化来研究上升时间与径向距离之间的关系。
当 V(pp)大于 1.0-1.5 mV 时，SFAP 上升时间相对不变。对于 V(pp)小于 1.0-1.5 mV，上升时间对径向距离变化的灵敏度显著增加。
尽管在肌肉纤维附近，SFAP 上升时间实际上不受径向距离变化的影响，但未来的工作有必要证实使用上升时间估计细胞内动作电位 (IAP) 去极化相变化的假设。
这些研究对于诊断和跟踪患有肌肉萎缩症或肌病患者的治疗结果很有用，已知这些疾病会伴随着 IAP 持续时间的严重变化。
