[Neuron contractile and electrical activities as affected by colchicine]

The purpose of this investigation was to analyze the contractile activity of traumatized nerve cell processes and to try to inhibit their retraction by colchicine solution. Isolated living neurons of mollusks (Lymnaea stagnalis and Planorbis comeus vulgaris) were studied using phase contrast and time-lapse microvideorecording. In the control group, contractile activity of nerve cell processes in Ringers solution was detected in 92% of cases. Application of colchicine resulted in the inhibition of retraction of nerve fibers in 86% of neurons. In the experiments designed to study neuron electrical activity, leech Retzius neurons were used. It was found that ganglion incubation in colchicine solution of increased the frequency of spontaneous pulse activity from 0.22 to 0.75 imp/s. The amplitude of spontaneous potentials decreased from 46.9 to 37 mV, the threshold was reduced by 18%, spontaneous spike duration increased from 4.3 ms to 7.1 ms, while the latent period of the response to irritating stimulus increased from 25.0 to 37.9 ms. During the irritation with a frequency of 7-10 Hz, neuron generated higher frequency of pulse activity, than in norm. Thus, it was possible to show, that cochicine can inhibit the contractive activity of the traumatized nerve cell processes, preserving an electroexcitable membrane in a satisfactory state. These results suggest that it is possible to partially inhibit the nerve fiber retraction in vivo, thus preventing the diastasis increase in the nerves that impedes their contact surgical approximation and promotes the development of a massive scar in severed area.