Hill R H, Govind C K
J Comp Neurol. 1983 Aug 10;218(3):327-33. doi: 10.1002/cne.902180308.
The form of the fast closer excitor (FCE) and the slow closer excitor (SCE) motoneurons to the closer muscle in the claw of the lobster Homarus americanus was determined by injecting cobalt chloride or Lucifer Yellow into their respective somata. Both neurons are monopolar with the single neurite rising vertically to the dorsal surface of the ganglion, then travelling along this surface to where it gives off its dendrites before entering the second nerve root as an axon. The FCE and SCE motoneurons, however, differ in their dendritic form in several respects. First, the FCE completely lacks an anterior dendritic field, which is well elaborated in the SCE. Second, the FCE has fewer large primary dendrites in its posterior field than the SCE. Third, the posterior dendritic field of the FCE is not as extensive as that of the SCE. Fourth, the axon of the FCE originates from one of the posterior primary dendrites while that of the SCE is an axial extension of its neurite. Thus the SCE has a more elaborate dendritic field than the FCE, which may account for its greater excitability. For instance, recordings from intact lobsters show that the SCE has a lower firing threshold and is active for longer periods of time and at higher frequencies than the FCE.
通过向美洲螯龙虾爪中闭肌的快速闭合激发神经元（FCE）和慢速闭合激发神经元（SCE）的胞体注射氯化钴或荧光黄，确定了这两种运动神经元的形态。这两种神经元都是单极的，单一神经突垂直上升至神经节的背表面，然后沿着该表面延伸至其发出树突的位置，之后作为轴突进入第二神经根。然而，FCE和SCE运动神经元在树突形态的几个方面存在差异。首先，FCE完全没有前树突场，而SCE的前树突场发育良好。其次，FCE后树突场中的大型初级树突比SCE少。第三，FCE的后树突场不如SCE广泛。第四，FCE的轴突起源于后初级树突之一，而SCE的轴突是其神经突的轴向延伸。因此，SCE的树突场比FCE更复杂，这可能解释了它更强的兴奋性。例如，对完整龙虾的记录表明，SCE的放电阈值更低，比FCE更活跃，且活跃时间更长、频率更高。
