Cytoplasmic syncytial interneuronal connection in molluscs

The absolute criteria developed by the authors have been presented; they allow revealing cytoplasmic syncytial connections between processes of nerve cells in vivo and in vitro at the light microscopy level by using classical methods and time lapse videoshooting in the phase contrast. With aid of electron microscopy, metastable membrane contacts and their perforations, cytoplasmic syncytial interneuronal pores, and fusion of nerve processes are demonstrated. In the culture of isolated molluscan neurons, the process of formation of syncytial connections between processes of the same neuron or of different neurons is reproduced. Processes of one neuron, which have syncytial connection with another neuron, are shown to remain viable after death of its neuronal soma. The cytoplasmic varicosities formed on processes of one neuron are able to overcome the place of syncytial contact with processes of another neuron and to move to the body of the latter. A hypothesis is put forward that the cytoplasmic syncytial connection between nerve processes is formed under the conditions of the absence of their glial sheaths.