Effects of Cannabinoid Administration on Planarian Feeding Responses

Undergraduate #60
Discipline: Biological Sciences
Subcategory: Cell and Molecular Biology

Christina Ranney - University of the District of Columbia
Co-Author(s): Annie Bagga and Rosie Sneed, University of the District of Columbia, Washington, D.C.

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The endocannabinoid system (ECS) regulates numerous physiological functions including pain, memory, reproduction, and energy balance in mammals. One of these functions, energy balance, regulates the feeding response and food intake. Components of the ECS such as the endogenous ligand anadamide have been identified in planarians and we hypothesize that the planarian ECS is subject to pharmacological manipulation in a manner similar to that of mammals. Specimens of Girardia tigrina (Girard, 1850), the North American brown planarian, were treated with the cannabinoid agonist WIN 55,212-2 (5 μM or 10 μM) or appropriate controls (media only or DMSO solvent control) for 90 minutes and extrusion of the pharynx served as a positive feeding response. Thirteen percent of animals in the 5 μM group showed a positive feeding response compared to 100 percent positive response in animals treated with 10 μM. To block the effect of WIN 55,212-2, planarians were pretreated with rimonabant (10 μM, 20 μM, and 30 μM), a cannabinoid antagonist 2 hours before treatment with the cannabinoid agonist. A concentration of 30 μM rimonabant reduced the positive feeding response to 11% compared to 100% in controls. These data indicate that cannabinoids can regulate the feeding response in planarians and may work through a receptor. Future studies will investigate the underlying cellular mechanisms of this response to determine how closely it parallels the actions of cannabinoids in other animals such as mammals.

Funder Acknowledgement(s): Supported by NIH Award T36GM101997-02

Faculty Advisor: Rosie Sneed,