Cannabinoids modulate food preference and consumption inDrosophila melanogaster

Abstract

Cannabinoids have an important role in regulating feeding behaviors via cannabinoid receptors in mammals. Cannabinoids also exhibit potential therapeutic functions in Drosophila melanogaster, or fruit fly that lacks cannabinoid receptors. However, it remains unclear whether cannabinoids affect food consumption and metabolism in a cannabinoid receptors-independent manner in flies. In this study, we systematically investigated pharmacological functions of various cannabinoids in modulating food preference and consumption in flies. We show that flies display preferences for consuming cannabinoids, independent of their sensory functions. Interestingly, phyto- and endo- cannabinoids exhibit an inhibitory effect on food intake. Unexpectedly, the non-selective CB1 receptor antagonist AM251 attenuates the suppression of food intake by endocannabinoids. Moreover, the endocannabinoid anandamide (AEA) and its metabolite inhibit food intake and promote resistance to starvation, possibly through reduced lipid metabolism. Thus, this study has provided insights into a pharmacological role of cannabinoids in feeding behaviors using an adult Drosophila model.

Cannabinoids differentially modulate behavioral and developmental responses to ethanol in Drosophila

“…Amongst the phytocannabinoids, pre-treatment with 0.1 mg/ml and 1mg/ml CBD significantly reduced the ethanol preference index on day 2, but not on day 1 (Figures 1B and 1C). In line with our previous study (He et al, 2021), the average food consumption of flies was significantly decreased with CBD at the higher concentration (Figures S1B), but not the low concentration (Figure S1A). In addition, we also assessed the preference for ethanol with various phytocannabinoids including CBDV, CBC and CBG at 0.1 mg/ml.…”

“…Previous studies using the Drosophila model have highlighted the protective role of cannabinoids in food intake (He et al, 2021), seizure (Jacobs and Sehgal, 2020), paraquat-evoked toxicity (Jimenez-Del-Rio et al, 2008) and cardiac function (Gómez et al, 2019). However, it remains unexplored whether cannabinoids affect ethanol responses in Drosophila which has been shown to be effective in modelling complex ethanol behaviors in mammals.…”

“…Eight adult male flies were transferred into a vial containing 1% agarose with four 5 μl glass capillaries (VWR, USA). The capillaries were inserted from the top of the vial via adaptors made of pipette tips (He et al, 2021). Following pre-treatment with cannabinoid-containing liquid food or control liquid food for two days, the flies were presented with two capillaries filled with normal liquid food and the remaining with normal liquid food + 15% ethanol.…”

“…Furthermore, emerging studies in Drosophila have documented the therapeutic effects of cannabinoids in food intake and various diseases including cardiovascular disease, Parkinson’s disease and seizure. Cannabinoids exhibited an inhibitory effect on food intake presumably through reduced lipid metabolism (He et al, 2021). Prolonged inhalation of marijuana increased cardiac contractility in adult flies (Gómez et al, 2019).…”

Vapor exposure to Δ9-tetrahydrocannabinol (THC) slows locomotion of the Maine Lobster (Homarus americanus)

“…The present results and the work on lobster neuromuscular junctions (Turkanis and Karler, 1988) suggest that THC has specific neuropharmacological effect, however, there does not appear to be a vertebrate endocannabinoid receptor (CB 1 or CB 2 ) expressed in the lobster or crayfish (Elphick and Egertová, 2009); this is similar to behavioral effects in Drosophila melanogaster (He et al, 2021) which likewise lack CB 1/2 analogs. This turns attention to the possibility that THC acts in the lobster via temperature activating (Chen, 2015) transient receptor potential (TRP) channels.…”