ACTION CURRENTS AND SKELETAL MUSCLE ELECTROPHYSIOLOGY

在过去的六年里，我们使用我们的室温，生物磁性 电流探头进行一系列独特的磁场测量 由神经和肌肉中的细胞动作电流产生。 平行于 在这些实验中，我们开发了数学模型， 生物磁场对细胞动作电流的影响，主要结论 磁记录技术所提供的，在我们现在的限制范围内， 了解详细，更好的定量信息， 比传统的活跃神经和肌肉细胞的电生理学 细胞外电测量。 一种定量准确的测量 细胞内动作电流和跨膜动作电位 这些电流产生的电磁波甚至可以通过磁性获得， 穿透细胞膜，避免细胞膜损伤， 常规微量移液管。 该技术还提供了一个直接 细胞内电导率的测量，正如我们最近证明的那样， 一个巨大的轴突在小龙虾和小龙虾中。 我们建议利用 磁技术研究电生理学的优势 骨骼肌。 首先，我们将进行一系列测量， 暴露动物单个运动单元的电磁信号 通过我们的数学模型， 在肌肉之间的关系的理论描述 磁记录动作电流和电记录动作电流 细胞内和细胞外动作电位，并确定 肌肉纤维束的有效电导率。 这些 结果应该为我们提供基本的知识，最终将有助于 了解传统的EMG记录和非侵入性磁记录， 人类骨骼肌的记录。 数量特征和 磁测量的简单性使得磁记录技术 非常适合于监测可能的不同生理 肌肉疾病的发展阶段。 我们将测试这一点， 来自肌肉萎缩小鼠模型的后肢肌肉的侵入性记录 营养不良 这些实验应该有助于识别可能的特征 健康和患病肌肉之间的电生理差异，以及 可以为肌肉组织中的药物治疗提供生理时间阈值， 和神经肌肉疾病。 最后，我们将评估我们的磁 技术作为一种完全非侵入性的测量时间过程， 肌肉疾病 我们将研究限制肌肉使用的影响， 它最近报道可能抑制肌肉萎缩症。

For the past six years, we have used our room-temperature, Biomagnetic Current Probe to conduct a unique series of measurements of magnetic fields produced by cellular action currents in nerves and muscle. In parallel to these experiments, we have developed mathematical models that relate the biomagnetic field to cellular action currents, with the major conclusion that the magnetic recording technique provides, within limits that we now understand in detail, better quantitative information about the electrophysiology of active nerve and muscle cells than the conventional extracellular electric measurements. A quantitatively-accurate measure of the intracellular action currents and the transmembrane action potential generated by these currents can even be obtained magnetically without penetrating the cell membrane, avoiding the membrane damage caused by conventional micropipettes. The technique also provides a direct measurement of intracellular conductivity, as we recently demonstrated for a single giant axons in the crayfish and earthworm. We propose to utilize the advantages of magnetic techniques to study the electrophysiology of skeletal muscle. First we will conduct a series of measurements of electric and magnetic signals from single motor units in exposed animal muscles to establish, by means of our mathematical models, a firm theoretical description of the relationship in muscle between the magnetically-recorded action current and the electrically-recorded intracellular and extracellular action potentials, and to determine effective electrical conductivities for muscle fiber bundles. These results should provide us with basic knowledge that will ultimately aid in understanding both conventional EMG recordings and non-invasive magnetic recordings from skeletal muscle in humans. The quantitative features and simplicity of magnetic measurements make the magnetic recording technique highly appropriate for monitoring of possible different physiological stages in the development of muscular diseases. We will test this by invasive recordings on the hind-limb muscles from a mouse model of muscular dystrophy. These experiments should help identify possible characteristic electrophysiological differences between healthy and diseased muscle, and may provide physiological time thresholds for drug therapies in muscular and neuromuscular diseases. Finally, we will evaluate our magnetic technique as a totally non-invasive measurement of the time-course of muscular disease. We will examine the effects of restricted muscle use and its recently reported possible inhibition of muscular dystrophy.