Counter S A, Borg E, Lännergren J
Acta Physiol Scand. 1981 Jan;111(1):105-8. doi: 10.1111/j.1748-1716.1981.tb06711.x.
The basic contraction properties of the solitary avian middle ear muscle, the M. stapedius, was investigated in chicken, Gallus gallus, by a sensitive tension transducer. Previous experimental studies on the in situ muscle preparation revealed both fast and slow components in the muscle's physiological responses. In the present study, brief electrical stimulus pulses delivered to the "isolated" M. stapedius elicited rapid twitch contractions with average tension levels of 46 mN for maximal stimulation. The contraction time was 15 ms, the half relaxation time was 15 ms and the total twitch time was 54 ms. Repetitive stimulation (2.5-200 Hz) revealed maximum summation of responses at 10-20 Hz and apparent complete fusion at 160 Hz. Peak tension at 160 Hz ranged from 150 mN to 200 mN. The twitch tetanus ratio was found to be 0.25. In earlier experiments with an in situ preparation, a slow component was observed in the physiological responses. However, this slow component was not seen in the single twitch responses or the responses or the response to repetitive stimulation in the present study. The M. stapedius of Gallus gallus was found to be a "fast" muscle by conventional terminology. Its contraction time is slightly shorter than the contraction times of the M. stapedius in mammals such as the cat (21 ms) and the rabbit (22 ms). These findings are consistent with earlier morphological studies which show the M. stapedius of Gallus gallus to have the features of a fast twitch muscle.
利用灵敏的张力换能器，对家鸡（原鸡）单独的中耳肌肉——镫骨肌的基本收缩特性进行了研究。先前对原位肌肉标本的实验研究揭示了该肌肉生理反应中的快速和慢速成分。在本研究中，向“分离出的”镫骨肌施加短暂的电刺激脉冲，引发了快速的抽搐收缩，最大刺激时平均张力水平为46毫牛顿。收缩时间为15毫秒，半松弛时间为15毫秒，总抽搐时间为54毫秒。重复刺激（2.5 - 200赫兹）显示，在10 - 20赫兹时反应达到最大总和，在160赫兹时明显完全融合。160赫兹时的峰值张力范围为150毫牛顿至200毫牛顿。抽搐 - 强直比为0.25。在早期的原位标本实验中，在生理反应中观察到一个慢速成分。然而，在本研究的单次抽搐反应或对重复刺激的反应中未见到这个慢速成分。按照传统术语，家鸡的镫骨肌被发现是一块“快速”肌肉。其收缩时间略短于猫（21毫秒）和兔子（22毫秒）等哺乳动物的镫骨肌的收缩时间。这些发现与早期的形态学研究一致，早期研究表明家鸡的镫骨肌具有快速抽搐肌肉的特征。
