Sydnes G, Walløe L
Acta Physiol Scand. 1980 Aug;109(4):439-45. doi: 10.1111/j.1748-1716.1980.tb06618.x.
The slowly adapting stretch receptor in the abdomen of freshwater crayfish (Astacus fluviatilis) was investigated to determine its properties under dynamic conditions. An in situ preparation was used; the necessary dissection did not involve the receptor organ or its immediate surroundings. Sinusoidal variations in the angle of flexion in the joint to which the receptor organ was connected, were generated by a feed-back controlled stretcher. Nerve spiked recorded from the axon of the receptor neurone and information about angle of flexion in the joint obtained by position transducers, were fed into a computer. Fourier transforms were performed on both input and output data to determine the amplitude of the 0. and 1. harmonic together with the phase of the 1. harmonic. The receptor organ was investigated for linearity up to 1.5 degrees input amplitude, and proved to be surprisingly linear within this range. In addition, the transfer function of the receptor organ was determined by stimulating it with small-amplitude sinusoidals with different frequencies. With a steady flexion of 35-40 degrees in the joint, the gain of the receptor organ increased 5-6 times when the modulation frequency of the input signal was increased from 0.1 to 5 cycles/s. A maximum in gain was constantly found at about 5 cycles/s, with a rapid fall towards 0 when the modulation frequency was increased further. A change in phase lead from positive (leading output) to negative with change in sign about 1 cycle/s was also found. These results resemble the results found by investigators of isolated preparations. A "hold" property is probably a part of the overall property of the receptor organ together with an element of Maxwell type. An element of the form h(s) = ksn with n approximately 0.45 is also a part of the transfer function of the receptor organ, although the physiological parallel to this element is uncertain.
对淡水小龙虾（Astacus fluviatilis）腹部的慢适应性牵张感受器进行了研究，以确定其在动态条件下的特性。采用了原位制备方法；必要的解剖操作未涉及感受器器官或其紧邻的周围组织。通过反馈控制的拉伸器产生与感受器器官相连关节的屈曲角度的正弦变化。从感受器神经元的轴突记录的神经冲动以及通过位置传感器获得的关节屈曲角度信息，被输入到计算机中。对输入和输出数据都进行了傅里叶变换，以确定零次和一次谐波的幅度以及一次谐波的相位。研究了感受器器官在输入幅度高达1.5度时的线性度，结果证明在此范围内它具有惊人的线性。此外，通过用不同频率的小幅度正弦波刺激感受器器官来确定其传递函数。当关节稳定屈曲35 - 40度时，输入信号的调制频率从0.1增加到5赫兹时，感受器器官的增益增加了5 - 6倍。增益最大值始终出现在约5赫兹处，当调制频率进一步增加时，增益迅速降至零。还发现随着调制频率在约1赫兹处符号变化，相位超前从正（输出超前）变为负。这些结果与对离体标本研究的结果相似。“保持”特性可能是感受器器官整体特性的一部分，同时还具有麦克斯韦型元件。形式为h(s) = ksn且n约为0.45的元件也是感受器器官传递函数的一部分，尽管与该元件对应的生理机制尚不确定。
