Completely isolated molluscan neurons. An ultrastructural study.

The neurons of the molluscs Lymnaea and Helix isolated by fermentative digestion followed by mechanical treatment do not differ ultrastructurally from intact ones. These cells have sufficient metabolic reserves and incorporate into RNA 8% of the total radioactive pool, even more than neurons in ganglia under equal conditions. Neuronal damage can occur, mainly during the pipetting, and this is usually expressed in vacuolization of the cytoplasm. It is important to note that alterations in cell ultrastructure develop earlier than changes in the membrane electrical properties. The surface of the isolated neurons is enlarged two-fold due to the infoldings of the cell membrane. So, the specific resistance of soma membrane of these neurons was calculated as 78 +/- 13 komega-sq. cm. On the surface of isolated neurons scraps of glial and neuronal processes not connected with their own cell bodies, and as a consequence not powerful, are sometimes found. Some endings of the neuronal processes on the surface of isolated neurons are ultrastructurally similar to the axo-somatic synapses.