Contractile and Electrical Activity of Neurons on Exposure to Colchicine.

The aim of the present work was to study the contractile activity of traumatized nerve cell processes and to attempt to inhibit their retraction using a solution of colchicine. Experiments were performed on living isolated neurons from freshwater mollusks ( Lymnaea stagnalis and Planorbis corneus vulgaris), which were studied in phase contrast conditions using time-lapse microvideo recordings. Contractile activity of nerve cell processes was seen in 92% of cases in control conditions in Ringer’s solution. Colchicine inhibited nerve process contraction in 86% of neurons. Experiments addressing neuron electrical activity were performed on leech Retzius neurons. Incubation of ganglia in colchicine solution was found to increase the frequency of spontaneous spike activity from 0.22 to 0.75 spikes/sec. The amplitude of spontaneous potentials decreased from 46.9 to 37 mV, the threshold decreased by 18%, the duration of spontaneous spikes increased from 4.3 to 7.1 msec, and the latent period of responses to stimuli increased from 25.0 to 37.9 msec. In conditions of stimulation at 7–10 Hz, neurons generated spike activity at higher frequencies than in control conditions. Thus, our experiments showed that colchicine can inhibit the contractile activity of traumatized nerve cell processes, keeping the electrically excitable membrane in a satisfactory condition. It follows that attempts can be made in vivo to produce partial inhibition of nerve fiber contraction, thus preventing increases in neuron diastasis, which prevent surgical approximation to the point of contact and promote the development of massive scars at transection sites. [ABSTRACT FROM AUTHOR]