Wiens T J
Department of Zoology, University of Manitoba, Winnipeg, Canada.
J Neurobiol. 1989 Jul;20(5):458-69. doi: 10.1002/neu.480200514.
Crustaceans are characteristically parsimonious in their neuromuscular innervation. In extreme instances, a single efferent axon, excitatory or inhibitory, may innervate two or more muscles that have totally different actions. In particular, the inhibitory axons of the reptantian decapod leg have been reported, in various studies within four different infraorders, to innervate anywhere from one to all seven of the leg's distal muscles and to vary in number from two to four. These axons' often inexplicable combinations of target muscles have in many cases precluded interpretation of their behavioral significance. Recent findings reviewed in this paper suggest that in fact all reptants share the same three inhibitory axons: one is a universal common inhibitor, making synaptic connections within all leg muscles; the other two are specific (single-target) inhibitors of the opener and stretcher muscles, respectively (muscles which share a single excitatory axon as their sole source of activation even though they act on different joints). The literature suggests two distinct roles in the control of limb movement for these two classes of inhibitors.
甲壳类动物在神经肌肉支配方面的特点是极为节俭。在极端情况下，一条传出轴突，无论是兴奋性的还是抑制性的，可能会支配两种或更多具有完全不同作用的肌肉。特别是，在四个不同亚目中的各种研究都报道，爬行类十足目动物腿部的抑制性轴突，支配着腿部远端肌肉中的一到全部七块肌肉，数量从两根到四根不等。这些轴突对目标肌肉的组合常常令人费解，在许多情况下妨碍了对其行为意义的解读。本文所综述的最新研究结果表明，实际上所有爬行类动物都共有三条相同的抑制性轴突：一条是通用的共同抑制剂，在所有腿部肌肉内形成突触连接；另外两条分别是开肌和伸肌的特异性（单靶点）抑制剂（这两块肌肉共享一条兴奋性轴突作为其唯一的激活源，尽管它们作用于不同的关节）。文献表明这两类抑制剂在肢体运动控制中发挥着两种不同的作用。
