Arbuthnott E R, Gladden M H, Sutherland F I
Department of Physiology, Trinity College, Dublin, Eire.
J Anat. 1989 Apr;163:183-90.
Six muscle spindles and three muscle spindle poles from four rat soleus muscles have been sectioned serially at 1 micron intervals to trace the motor innervation by light microscopy. Forty myelinated axons had 92 endings on the intrafusal muscle fibres. 67.5% of these axons supplied a single type of muscle fibre only, 22.5% to dynamic bag1 (Db1) fibres, 15% to static bag2 (Sb2) fibres and 30% to chain fibres. The rest supplied more than one fibre type, 5% supplying the Db1 and one chain fibre, 20% supplying the Sb2 and chain fibres, but 7.5% (three axons) supplied all the fibre types together. Apart from these three axons all the fusimotor axons would be expected to have a clear dynamic or static action on the Group Ia discharge. Whilst for the cat entirely non-specific distribution does not exist, or at least is very rare, since only a small proportion of the rat fusimotor axons were in this category we conclude that fusimotor distribution in rats and cats is essentially similar.
对取自四只大鼠比目鱼肌的6个肌梭和3个肌梭极进行了连续切片，切片间隔为1微米，以便通过光学显微镜追踪运动神经支配情况。40条有髓轴突在梭内肌纤维上有92个终末。这些轴突中有67.5%仅支配单一类型的肌纤维，22.5%支配动态囊袋1（Db1）纤维，15%支配静态囊袋2（Sb2）纤维，30%支配连锁纤维。其余的支配不止一种纤维类型，5%支配Db1纤维和一条连锁纤维，20%支配Sb2纤维和连锁纤维，但7.5%（三条轴突）同时支配所有纤维类型。除了这三条轴突外，预计所有肌梭运动轴突对Ia类放电都有明确的动态或静态作用。虽然猫不存在完全非特异性的分布，或者至少非常罕见，但由于只有一小部分大鼠肌梭运动轴突属于这一类别，我们得出结论，大鼠和猫的肌梭运动分布基本相似。
