Taylor R G, Fowler W M, Lieberman J S, Ullmann N, Abresch R T
Arch Phys Med Rehabil. 1980 Apr;61(4):151-9.
The purpose of this study was to evaluate a technique for in vitro study of mouse skeletal muscle, to determine if paired stimuli would allow estimation of new time parameters of contraction. Conventional tension measurements were obtained, plus the time measurements from the paired stimulus studies. The muscles were also subjected to fatigue by repetitive tetanization. A fast muscle (extensor digitorum longus or plantaris) and a slow muscle (soleus) were studied in each preparation. Studies were conducted at physiologic (35C) and at nonphysiologic (20C) temperatures. Data obtained indicate that this isometric in vitro method allows subdivision of results into 3 categories of effect due to treatment related to the functional muscle compartments: 1) chronotropic-excitation contraction coupling mechanisms, 2) inotropic- contractile elements, and 3) metabolic (fatigue)-energy supply mechanisms. When results as 20C were compared with physiologic temperature, a negative chronotropic effect was observed for all parameters in all 3 muscles. A positive inotropic effect was observed for twitch with no change or a negative effect for all other tension parameters. The lower temperature produced slight protection from fatigue. Models were developed to demonstrate how data from isometric studies fit the original concepts developed using isotonic methods. The model and method should prove of value in detecting the acute effect of drugs or of other therapy imposed on skeletal muscles.
本研究的目的是评估一种用于小鼠骨骼肌体外研究的技术，以确定成对刺激是否能用于估计新的收缩时间参数。获得了传统的张力测量值，以及成对刺激研究中的时间测量值。肌肉还通过重复强直刺激而疲劳。在每个标本中研究了一块快肌（趾长伸肌或跖肌）和一块慢肌（比目鱼肌）。研究在生理温度（35℃）和非生理温度（20℃）下进行。所获得的数据表明，这种等长体外方法可将结果细分为与功能性肌肉区室相关的处理所产生的3类效应：1）变时性 - 兴奋收缩偶联机制，2）变力性 - 收缩元件，以及3）代谢（疲劳） - 能量供应机制。当将20℃时的结果与生理温度下的结果进行比较时，在所有3块肌肉中的所有参数上均观察到负性变时效应。对于单收缩观察到正性变力效应，而所有其他张力参数无变化或呈负性效应。较低温度对疲劳有轻微的保护作用。建立了模型以证明等长研究的数据如何符合使用等张方法所提出的原始概念。该模型和方法在检测施加于骨骼肌的药物或其他治疗的急性效应方面应具有价值。
