ACTION CURRENTS & SKELETAL MUSCLE ELECTROPHYSIOLOGY

拟议研究的目的是研究生物磁信号，如果 正常人骨骼肌单纤维和多细胞活性 动物，肌肉可塑性的动物模型，正常人类受试者，和 患有某些肌肉疾病的患者。 在过去的三年里，我们 已经使用我们的室温，生物磁电流探针进行了 对细胞产生的磁场进行独特的一系列测量 肌肉中的动作电流（AC）。 与此同时，我们开发了 将生物磁场与细胞AC联系起来的数学模型， 根据磁记录技术提供的主要结论， 在我们现在详细了解的范围内， 关于活动肌肉细胞的电生理学信息， 用常规的细胞外电记录获得。 一 细胞内AC和跨膜作用的定量测量 这些电流产生的电势甚至可以通过磁性获得 而不用微量吸管穿透细胞。 或者， 磁记录AC结合微电极测量， 电位可以提供细胞内的电导率和膜 电容 我们已经测量了来自整个地球的电磁信号， 肌肉、单个运动单位和来自哺乳动物肌肉的单个纤维， 使我们能够通过我们的数学模型建立一个公司 理论上描述了磁- 记录的AC和电记录的细胞内和细胞外 动作电位，并确定有效电导率 肌肉纤维束的位置 我们还展示了AC与 收缩力 虽然必须继续增加这种 基本知识，我们现在有足够的信息，以确保生产力 我们的研究扩展到检查正常肌肉膜的变化 physiology. 技术进步使我们能够获得一种独特的， 高分辨率超导量子干涉仪 磁力计在非侵入性记录能力方面无与伦比 磁图（MMG）。 通过应用我们所有的新磁记录技术 技术来研究实验引起的肌肉变化，我们 应该能够获得关于肌肉可塑性的新信息， 在废用性萎缩、工作引起的肥大和 去神经 通过应用这些新技术来检查 肌肉疾病患者，我们应该能够开始阐明 肌肉疾病的潜在机制。

The objective of the proposed research is to study biomagnetic signals if single fiber and multicellular activity in skeletal muscle of normal animals, animal models of muscular plasticity, normal human subjects, and patients with certain muscular disorders. For the past three 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 (ACs) in muscle. In parallel, we have developed mathematical models that relate the biomagnetic field to cellular ACs, with the major conclusion that magnetic recording techniques provide, within limits that we now understand in detail, better quantitative information about the electrophysiology of active muscle cells that can be obtained with conventional extracellular electric recording. A quantitative measure of the intracellular ACs and the transmembrane action potential generated by these currents can even be obtained magnetically without penetrating the cell with micropipette. Alternatively, the magnetically-recorded AC combined with a microelectrode measurement of potential can provide the intracellular conductivity and membrane capacitance. We have measured electric and magnetic signals from whole muscles, single motor units, and single fibers from, mammalian muscles, enabling us to establish, by means of our mathematical models, a firm theoretical description of the relationship between the magnetically- recorded AC and the electrically-recorded intracellular and extracellular action potentials, and to determine effective electrical conductivities for muscle fiber bundles. We have also shown the relationship of ACs to contractile force. While it is imperative to continue adding to such basic knowledge, we now have sufficient information to assure a productive extension of our research to examine alterations of normal muscle membrane physiology. Technological advances have enabled us to obtained a unique, high-resolution Superconducting Quantum Interference Device (SQUID) magnetometer that is unsurpassed in its ability to noninvasively record the magnetomyogram (MMG). By applying all of our new magnetic recording techniques to study experimentally-induced alterations of muscle, we should be able to obtain new information on muscle plasticity, manifest under such conditions as disuse atrophy, work-induced hypertrophy, and denervation. By applying these new techniques to examine tissues of patients with muscular disorders, we should be able to begin elucidating mechanisms underlying muscle disease processes.