sodium-bromide and Neuroblastoma

Differentiated C1300 mouse neuroblastoma cells were treated with 10(-4)-10(6) M gamma-aminobutyric acid (GABA) and/or sodium bromide (NaBr) for 2 days and then fixed. Quantitative studies revealed an increase in the length and branching of the processes, as well as an increase in the number of cells when compared to the controls. It is suggested that the above changes contribute to the augmentation of specialized contacts between cells and processes as well as the further maturation of the primitive stages of synaptogenesis as discussed.

Topics: Animals; Bromides; Cell Differentiation; Clone Cells; gamma-Aminobutyric Acid; Mice; Neoplasms, Experimental; Neuroblastoma; Neurons; Sodium; Sodium Compounds; Synapses

Sodium bromide was applied in vitro to mouse neuroblastoma cells of different ages for short and long periods (2 h to 10 days). The changes observed light-and-electron microscopically were similar to those described earlier after GABA treatment. Coated vesicles proliferated and originated by pinching off from the Golgi complex and from the rough endoplasmic reticulum. Numerous coated vesicles were continuous with the plasma membrane, especially near zones in which electron-dense material aggregated at the inner aspect of the plasmalemma. Small invaginations, similar in ultrastructure to coated vesicles, were also formed. It is unclear whether the coated vesicles or the dense plasmalemma invaginations contribute to the "undercoating" by fusing with the adjacent electron-dense plasma membrane. There was a distinct increase in the number and area of specialized contacts (intermediate junctions and zonulae adhaerentes) between cells and their processes. A floccular or filamentous electron-dense substance varying in amount and appearance was occasionally seen between the contacting membranes. Varicosities of terminal swellings of cell processes contained vesicles of variable size, shape and density, and also profiles of the smooth endoplasmic reticulum. Under the influence of sodium bromide, similar to the effect of GABA, mitochondria appeared within the varicosities, and primitive contacts (intermediate junctions) were formed between the terminal swellings and potential postsynaptic elements, which were absent in controls. Additionally, dense-core vesicles proliferated and aggregated at the cell periphery. They were often arranged linearly below the plasma membranes of perikarya and processes, and surrounded by a highly electron-dense substance. The similarity of the present findings to those obtained after GABA treatment and their relation to synaptogenesis are discussed.

Topics: Animals; Bromides; Cell Differentiation; Cell Line; Cell Membrane; Endoplasmic Reticulum; gamma-Aminobutyric Acid; Golgi Apparatus; Mice; Neuroblastoma; Neurons; Sodium; Sodium Compounds; Synaptic Vesicles

Growth cones of differentiated neuroblastoma cells in monolayer cultures were studied by electron microscopy. Morphological differentiation of the growth cone formation was induced by sodium bromide. Upon prolonged application of 10(-4) to 10(-5) M sodium bromide to the cultures, a peculiar or modified formation of the growth cone occurred. Growth cones lengthened gradually. The ultrastructure of the growth cone in contrast to the control was typified by a round to oval structure, midway being electron-dense and carrying laterally denser cytoplasmic protrusions. Bundles of microtubules, aggregates of many dense-cored vesicles, 70-150 nm in diameter, a few less electron-dense, as well as some agranular vesicles were present. Comparing the findings with previous ultrastructural accounts of growth cones of cultured ganglion cells or neuroblastoma cells, differences outnumbered similarities. The organization of the microtubule bundles and the abundance of dense-cored vesicles, sometimes extending distally was remarkable. The presence of an electron-dense substance, of unknown origin, extending laterally with the cytoplasmic protrusions has not been describe as yet.

Topics: Animals; Axons; Bromides; Cell Differentiation; Cell Line; Clone Cells; Dendrites; Ganglia, Sympathetic; Mice; Microscopy, Electron; Neuroblastoma; Sodium; Sodium Compounds; Synapses; Synaptic Vesicles