The fine structure of a rectifying electrotonic synapse
The fine structure of a rectifying electrotonic synapse
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整流电紧张突触的精细结构
作者：
R. Hanna;J. S. Keeter;G. Pappas
克氏原螯虾腹神经索腹神经节中的外侧巨轴突和运动巨轴突之间的突触是电子突触。连接膜变直，有利于外侧巨纤维向巨运动纤维的冲动传递。这种整流电子结由与普通节肢动物间隙连接无区别的紧密贴壁膜组成。并列的膜含有宽度约为12.5纳米的膜内颗粒。这些颗粒具有中心凹陷并且以中心到中心间距为约20 nm的松散有序阵列排列。唯一明显的形态学证据是突触前外侧巨纤维交界区附近的细胞质中存在小泡（直径约80 nm）。囊泡不存在于突触后巨大运动纤维的相邻细胞质中;然而，线粒体和滑管状内质网在巨大运动纤维的细胞质中更常见。
The synapses between the lateral giant axon and the giant motor axon found in the abdominal ganglia of the ventral nerve cord of the crayfish Procambarus clarkii are electronic. The junctional membrane rectifies, favoring impulse transmission from lateral giant fiber to giant motor fiber. This rectifying electronic junction consists of closely apposed membranes indistinguishable from ordinary arthropod gap junctions. The apposed membranes contain intramembrane particles that are approximately 12.5 nm in width. These particles have a central depression and are arranged in a loosely ordered array with a center-to- center spacing of about 20 nm. The only obvious morphological evidence of asymmetry is the presence of vesicles (about 80 nm in diameter) in the cytoplasm adjacent to the junctional region of the presynaptic lateral giant fiber. Vesicles are not present in the adjacent cytoplasm of the postsynaptic giant motor fiber; however, mitochondria and smooth tubular endoplasmic reticulum are more frequent in the cytoplasm of the giant motor fiber.