Donaldson P L, Josephson R K
J Neurobiol. 1981 Nov;12(6):545-59. doi: 10.1002/neu.480120604.
Fibers of the metathoracic extensor tibia muscle of the cricket Teleogryllus oceanicus are innervated by a slow excitatory axon (slow fibers), a fast excitatory axon (fast fibers), or by both slow and fast axons (dual fibers). Sectioning metathoracic nerve 5 removes the fast axon input to the muscle but not that of the slow axon. Following such partial denervation, the mechanical responses initiated by the slow axon increase progressively for at least 30 days; twitch tensions reach 5-10 times those of control muscles and tetanic tensions 10-30 times control values. After sectioning nerve 5, resting membrane potentials decrease in those fibers which originally received fast axon input and the input resistance of all fiber types increases, including that of slow fibers which are not innervated through nerve 5. Excitatory junctional potentials (EJPs) initiated by the slow axon become larger following partial denervation, accounting in part for the larger contraction amplitudes. The increased input resistance is adequate to account for the larger EJPs in slow fibers but not for the proportionally greater increase in EJP amplitude in fibers which were formerly dually innervated. The change in EJP amplitude is abrupt in slow fibers and gradual in formerly dual fibers.
大洋洲长蟋蟀后胸胫节伸肌的纤维由一条慢兴奋性轴突（慢纤维）、一条快兴奋性轴突（快纤维）或由慢、快轴突共同支配（双纤维）。切断后胸神经5会消除快轴突对肌肉的输入，但不会消除慢轴突的输入。在这种部分去神经支配后，由慢轴突引发的机械反应至少持续30天逐渐增强；单收缩张力达到对照肌肉的5 - 10倍，强直收缩张力达到对照值的10 - 30倍。切断神经5后，原本接受快轴突输入的那些纤维的静息膜电位降低，所有纤维类型的输入电阻增加，包括那些并非通过神经5支配的慢纤维。部分去神经支配后，由慢轴突引发的兴奋性突触后电位（EJP）变大，这部分解释了收缩幅度增大的原因。输入电阻的增加足以解释慢纤维中EJP变大的情况，但无法解释原本接受双重支配的纤维中EJP幅度按比例更大的增加情况。慢纤维中EJP幅度的变化是突然的，而原本接受双重支配的纤维中则是逐渐变化的。
