Electrophysiological activity of the brain of the mollusk Lymnaea stagnalis L. after cryopreservation in liquid nitrogen (−196°C)

Abstract

The study of the reversible suspension of the vital activity of neurons, as a part of nervous tissue, after their cryopreservation, is new and in demand. Long-term storage of a viable material at a temperature of liquid nitrogen (−196°C) opens new opportunities for biomedicine in the field of the establishment of cryobanks for nerve tissue transplants. In this work, the recovery of the electrophysiological activity of neurons after deep freezing, by an example of ganglia of the brain of the mollusk Lymnaea stagnalis L. was studied. The comparison of electric characteristics (membrane potentials, action potentials) of identified neurons of different ganglia was carried out in an organotypic culture of the mollusk cryopreserved brain and the brain not exposed to cryopreservation. The preservation of functional connections between identified RPeD1 interneurons of the pedal ganglion, interneurons VD1, VD4 and the area of the VA-cluster of the visceral ganglion was analyzed. The influence of a cryoprotector dimethylsulfoxide (DMSO) on functional connections between the identified neurons of the mollusk brain was studied. It was shown that the typical patterns of electric activity of neurons were restored after cryopreservation of the mollusk brain; neurons generated postsynaptic potentials (PSP), but functionally active connections between the identified neurons of different ganglia were not found. DMSO did not influence the functioning of connections between the neurons localized in different ganglia. Interruption of some connections between neurons could be caused by cryodamages in the neuropil and commissures, which is confirmed by the presence of the PSP of an atypical profile.