[Neuronal division or enucleation]

In this work,using the classical neurohistological Bielschowsky-Gros method, all the morphological phenomena were reproduced that were earlier interpreted by many authors as the signs of neuron division, budding and fission. It is suggested that these phenomena are associated with the effect of enucleation demonstrated in many cells of other tissue types exposed to different physical and chemical factors. The experiments were conducted in tissue culture, using the isolated neurons of the mollusk Lymnnaea stagnalis, in which the neural cells were treated with actin microfilament inhibitor cytochalasin B. Phase-contrast time-lapse video recording during 4-8 hours demonstrated the effects of nucleus displacement, ectopy and bulging up to almost complete fission of neuronal body. These effects reproduce the images obtained in static fixed preparations under "normal" and various experimental conditions. Sometimes, at the early experimental stages, the bulging of cytoplasm was also detected. Control experiments in which the neurons were treated with the culture medium containing cytochalasin B solvent dimethyl sulfoxide, showed no changes in neurons during 8-hour period. It is suggested that the images, interpreted earlier as neuron division or fission, could be explained by inhibition of actin microfilaments, which sometimes may develop spontaneously in cells experiencing individual metabolic changes compromising the cytoskeleton stability maintenance.