The smooth endoplasmic reticulum: structure and role in the renewal of axonal membrane and synaptic vesicles by fast axonal transport.

摘要: The spatial arrangement of the smooth endoplasmic reticulum (SER) was studied in 0.5-2 mum thick sections rat spinal and chick ciliary ganglia previously impregnated with heavy metal salts. Electron microscopy at low (10-5 V) or high (10-6 voltage showed SER as a continuous system extending probably from perikaryon to axon terminal. Tubules SER, which were running parallel direction axon, occasionally seen close apposition axonal membrane. Moreover preterminal region, anastomosed tubules formed subsurface 'primary network' gave rise deeper 'secondary made thinner tubules; synaptic vesicles bulging tip thin frequently observed. To specify role played by fast transport, chicken slighty compressed radioautographed 3 h after intracerebral injection [3-H]lysine. Quantitative analysis silver grain distribution indicated that labeled proteins, rapidly conveyed down piled up regions containing an accumulation profiles. On basis these results, it is concluded that: (1) appears intraaxonal pathway bridging terminal; (2) conveys macromolecular components transport; (3) macromolecules, are delivered membrane vesicles, transferred means connections SER.