Liu H P, Tay S S, Leong S K
Department of Anatomy, Faculty of Medicine, National University of Singapore, Singapore.
J Hirnforsch. 1997;38(1):107-17.
The present ultrastructural study investigated the innervation of the guinea pig pancreas, with special emphasis on the pancreatic ganglia and the sympathetic and parasympathetic boutons/terminals. The pancreatic ganglion cells, ensheathed in a thin layer of connective tissue, showed typical features of autonomic neurons. Each contained a prominent eccentric round nucleus with 1 to 5 nucleoli and a copious cytoplasm with many organelles. Synapses were scattered in the ganglion and were of the axodendritic type. Axosomatic synapses were not encountered even after examination of semiserial sections in one of the tissue blocks. Desmosome-like junctions (puncta adhaerentia) were found between somata of the ganglion cells, and between their dendrites, and also between somata of the ganglion cells and satellite cells. The sympathetic nerves supplying the pancreas were demonstrated by the 5-hydroxydopamine loading method. Axon terminals loaded with the false transmitter were filled with intensely stained small dense-cored vesicles. These were present in close contact with acinar cells, islet cells as well as smooth muscle cells of arterioles. No 5-hydroxydopamine loaded axon terminals or ganglion cells were observed within the ganglia. The preganglionic parasympathetic nerve fibres supplying the pancreas traveling with the vagus nerve were studied by sectioning the left vagus nerve at mid-cervical level. Three to 7 days after left cervical vagotomy, degenerating axon terminals containing small spherical agranular vesicles, together with degenerating dendrites and neuronal somata showing electron dense cytoplasm were encountered within the pancreatic ganglion. The satellite cells were hypertrophied, showing a pale cytoplasm in which were embedded degenerating axon terminals and dendrites. In conclusion, the present study described the normal structure of pancreatic ganglia, provided ultrastructural evidence of the presence of sympathetic and parasympathetic fibres in the pancreas of the guinea pig, and reported postsynaptic changes in the dendrites after mid-cervical sectioning of the left vagus nerve.
本超微结构研究对豚鼠胰腺的神经支配进行了调查，特别着重于胰腺神经节以及交感和副交感神经终扣/末梢。胰腺神经节细胞被一层薄的结缔组织包裹，呈现出自主神经元的典型特征。每个细胞都含有一个突出的偏心圆形细胞核，有1至5个核仁，以及一个含有许多细胞器的丰富细胞质。突触分散在神经节中，为轴-树突型。即使在其中一个组织块中检查了半连续切片后，也未发现轴-体突触。在神经节细胞的胞体之间、它们的树突之间，以及神经节细胞的胞体与卫星细胞之间发现了桥粒样连接（粘着斑）。通过5-羟多巴胺加载法显示了供应胰腺的交感神经。加载了假递质的轴突末梢充满了染色强烈的小致密核心囊泡。它们与腺泡细胞、胰岛细胞以及小动脉的平滑肌细胞紧密接触。在神经节内未观察到加载5-羟多巴胺的轴突末梢或神经节细胞。通过在颈中部切断左迷走神经，研究了与迷走神经一起走行的供应胰腺的节前副交感神经纤维。左颈迷走神经切断术后3至7天，在胰腺神经节内遇到了含有小球形无颗粒囊泡的退化轴突末梢，以及显示电子致密细胞质的退化树突和神经元胞体。卫星细胞肥大，其淡染的细胞质中嵌入了退化的轴突末梢和树突。总之，本研究描述了胰腺神经节的正常结构，提供了豚鼠胰腺中存在交感和副交感纤维的超微结构证据，并报告了左迷走神经颈中部切断后树突的突触后变化。
