Effects of nicotine withdrawal on the nervous system and behavior of C. elegans in males and hermaphrodites

Nicotine is an addictive psychoactive drug, and its discontinuation may cause withdrawal symptoms. Several studies observed sex differences in nicotine-addicted behavior, thought to be correlated to hormonal and neuro-anatomical differences.

C. elegans is a common model organism in neurobiological research, due to its easy maintenance, simple genetic manipulations execution, and lack of influence of sex hormones between the two sexes – hermaphrodites and males. In this research two species of worms were used: him-5 and him-5;dop-1, a mutant species without an active DOP-1 receptor.

We studied behavioral and neurological differences to nicotine withdrawal between males and hermaphrodites, and the two species.

To that end, we grew males and hermaphrodites separately in plates with OP50 and nicotine. Each plate was filmed for 15 minutes, then tracked, analyzed, and compared locomotion parameters.

We found opposite relation in him-5 male and hermaphrodite behavior – male locomotion speed in withdrawal was greater than in chronic exposure to nicotine, with no change overtime. In contrast, hermaphrodite locomotion speed in withdrawal and chronic exposure were the same, however, in chronic exposure there was a decrease in speed overtime.

In him-5;dop-1 we did not find locomotion speed differences between chronic exposure or withdrawal in both sexes. In both species there were no speed differences between the sexes.