The Effects of Cannabidiol and Serotonin on Anxiety-Like Behavior in Crayfish

Cannabidiol (CBD) is a cannabinoid that is being used as a new treatment for many mental and physical medical conditions, including anxiety. Serotonin (5-HT) is a neurotransmitter that has been shown to have many roles, including stabilizing mood. Crayfish are invertebrate animals that have been used as a model system to study human diseases. Crayfish are well suited to study the effect of CBD on anxiety due to their documented endocannabinoid system and anxiety-like behavioral traits. In this study, the effects of CBD on anxiety-like behavior in crayfish were investigated using a Light-Dark maze as a behavioral analysis tool. At the doses used, CBD did not independently show any influence on either the Light-Dark preference or the total position moves made by crayfish. 5-HT showed quite variable results compared to the saline solution. 5-HT injection significantly decreased time spent in the dark for crayfish injected with 2µg/g of CBD and significantly decreased movement for crayfish injected with 4µg/g of CBD. The dichotomous behavior of the 5-HT injected crayfish requires more study to determine if underlying factors can explain the varying responses. The concentrations of CBD may also need to be increased to properly examine its role in reducing anxiety.