Effect of nicotine on locomotion of Caenorhabditid elegans
The locomotion of the soil nematode Caenorhabditis elegans is a simple behavior that has been widely used to dissect genetic components of behavior, synaptic transmission, and muscle function. Numerous studies have reported that exogenous nicotine caused contractions and spastic paralysis of worms at a concentration of 30 mM. The aim of this study was to estimate nicotine-induced behavioral response of C. elegans wild-type (N2) L1 larvae. The L1 larvae were transferred to NGM plates containing 300 μM (–)-nicotine. The Parallel Worm Tracker was used to measure average locomotion speed and nicotine-induced paralysis in C. elegans [Ramot et al. (2008) PLoS ONE 3: e2208). The tracker utilizes a modifi ed web camera (attached to zoom stereo microscopes), which records the position of tens of worms in sequential video frames. In each experiment, approximately 40 worms were tracked for 30 s every 10 min. A rapid increase in the mean speed of worm locomotion (up to 2-fold) was observed after 10 min of exposure of L1 larvae to nicotine. At the same time, the lowest number of paralyzed and immobile worms was noticed. The lowest mean locomotion speed and the maximum of paralyzed individuals was observed after 40 min of nicotine treatment. It was followed by a recovery period within 60 min after exposure, during which the worms acquired tolerance. Further research will be undertaken to analyze the nicotine dose-dependent locomotion response of all developmental stages of C. elegans.