A cembranoid from tobacco prevents the expression of nicotine-induced withdrawal behavior in planarian worms.

Using an adaptation of published behavioral protocols, we determined that acute exposure to the cholinergic compounds nicotine and carbamylcholine decreased planarian motility in a concentration-dependent manner. A tobacco cembranoid (1S,2E,4R,6R,7E,11E)-cembra-2,7,11-triene-4,6-diol (4R-cembranoid), also decreased planarian motility. Experiments in the presence of 1 microM 4R-cembranoid did increase the IC50 for nicotine- but not carbamylcholine-induced decrease in planarian motility. When planarians were exposed for 24 h to either nicotine or carbamylcholine at concentrations near their respective IC50 values and then transferred to plain media, nicotine-exposed, but not carbamylcholine- or cembranoid-exposed worms displayed withdrawal-like distress behaviors. In experiments where planarians were pre-exposed to 100 microM nicotine for 24 h in the presence of 1 microM 4R-cembranoid, the withdrawal-like effects were significantly reduced. These results indicate that the 4R-cembranoid might have valuable applications for tobacco abuse research. This experimental approach using planarians is useful for the initial screening of compounds relevant to drug abuse and dependence.

The flatworm planaria as a toxicology and behavioral pharmacology animal model in undergraduate research experiences.

In this work we describe a series of simple protocols using planaria as an animal model in toxicology and behavioral pharmacology. These procedures have proven useful to provide significant research experience to undergraduate students, including coauthorship in peer-reviewed publications. The methods described in this work have proven useful to allow students to visualize concepts related to concentration-effect curves for toxicity and behavioral experiments, without the need to consider factors that must be taken into account when working with vertebrate animals.