poster abstractDrug addiction is a chronic, relapsing disease premised on compulsive drug seeking.
Previous work from our lab demonstrated that the nematode Caenorhabditis elegans
(C. elegans) can be used to examine the reinforcing properties of drugs of abuse. A
successful model for studying the reinforcing effects of drugs in C. elegans would
greatly aid efforts to discover potential therapeutic interventions for drug addiction.
The present study examined preference for morphine, ethanol, cocaine, and a
cannabinoid agonist (CB agonist) in C. elegans and the effect of naltrexone, an opioid
antagonist, on this behavior. Six-well agar test plates were utilized to test drug
preference. Each well had two circular target zones equidistant from the center; 4μl
of the targeted drug or water were placed in the center of one of the two target zones
within each well. Worms in one group were pre-treated with 10mM naltrexone, while
controls were pre-treated with 0.97 mM HCl for 30 min prior to testing. Worms in
each treatment group were then placed in the center of each well and allowed to move
freely for 30 minutes-images were captured at 10 and 30 minutes. Animals treated
with vehicle displayed a significant preference for the aforementioned drugs relative
to controls; naltrexone pretreatment significantly ameliorated this effect. Naltrexone
had no effect on food or chemoatractant preference, indicating that the effects of
naltrexone on drug preference are selective and not due to disruption in general
behaviors. These findings suggest that the reinforcing properties of drugs of abuse
can be examined in C. elegans and this model may be useful for screening potential
pharmacotherapies for drug abuse
