Kohno K, Noguchi N
Anat Embryol (Berl). 1986;173(3):361-70. doi: 10.1007/BF00318920.
Thin sectioning and freeze-fracturing have revealed the distribution of gap junctions and chemical synapses in the synaptic interface of the large myelinated club endings on the lateral dendrite of the goldfish Mauthner cell. In 12 samples of club endings fractured completely or nearly completely, the apposed synaptic membrane area averaged 39.090 microns2, of which 16.6% was occupied by gap junctions and about 4 to 5% by the active zones of chemical synapses. The numerical profile density (number per unit area of the synaptic membrane) of gap junctions varied greatly, from 1.78 to 6.30, and was mostly in inverse proportion to their size. The chemical synapses were located mainly in two places: in the circumferential rim of the synaptic membrane next to the widened extracellular space, and in the margins of intraterminal invaginations of the synaptic cleft. The axoplasm of the preterminal axon, just after losing its myelin sheath, was filled with microtubules, among which neurofilaments gathered into many small bundles. The correlation between the areas of gap junctions and the chemical synapses and the amplitude of the excitatory postsynaptic potentials (EPSP) is discussed.
薄切片和冷冻断裂技术揭示了金鱼莫氏细胞外侧树突上有髓大棒状终末突触界面中间隙连接和化学突触的分布情况。在12个完全或几乎完全断裂的棒状终末样本中，相对的突触膜面积平均为39.090平方微米，其中16.6%被间隙连接占据，约4%至5%被化学突触的活性区占据。间隙连接的数字轮廓密度（每单位突触膜面积的数量）变化很大，从1.78到6.30，且大多与其大小成反比。化学突触主要位于两个位置：在靠近细胞外间隙增宽处的突触膜圆周边缘，以及突触间隙终末内陷的边缘。终末前轴突刚失去髓鞘后，其轴浆充满微管，其中神经丝聚集成许多小束。文中讨论了间隙连接和化学突触的面积与兴奋性突触后电位（EPSP）幅度之间的相关性。
