Dumitru D, King J C, van der Rijt W, Stegeman D F
University of Texas Health Science Center at San Antonio 78284-7798.
Muscle Nerve. 1994 Nov;17(11):1301-7. doi: 10.1002/mus.880171109.
The extracellular morphology of single muscle fiber action potentials (SMFAPs) is anticipated by volume conductor theory to be triphasic. Single muscle fiber action potentials recorded during single muscle fiber studies (500 Hz to 20 kHz) usually appear triphasic; however, when recorded with an open bandwidth (1 Hz to 20 kHz) they are found to be biphasic. Fibrillation potentials recorded with a single fiber electrode and open bandwidth have identical biphasic morphologies as volitional SMFAPs. Computer simulations suggest that the intracellular action potential models currently used to derive simulated extracellularly recorded SMFAPs must have the repolarization phase considerably prolonged to yield the clinically recorded potentials. This implies that either the models presently used require significant modification, or there is some distortion of the transmembrane source current induced in needle recording studies such that biphasic and not triphasic potentials are detected.
根据容积导体理论，单肌纤维动作电位（SMFAPs）的细胞外形态预计为三相。在单肌纤维研究中（500赫兹至20千赫兹）记录的单肌纤维动作电位通常呈现三相；然而，当以开放带宽（1赫兹至20千赫兹）记录时，发现它们是双相的。用单纤维电极和开放带宽记录的纤颤电位具有与随意性SMFAPs相同的双相形态。计算机模拟表明，目前用于推导模拟细胞外记录的SMFAPs的细胞内动作电位模型必须将复极化阶段显著延长，以产生临床记录的电位。这意味着要么目前使用的模型需要重大修改，要么在针电极记录研究中诱导的跨膜源电流存在某种失真，以至于检测到的是双相而非三相电位。
