Meeting Abstract

P3-109    Endocannabinoids and paracannabinoids are associated with the seasonal transition from reproduction to feeding behavior in garter snakes Merlino, LJ*; Lin, L; Piomelli, D; Lutterschmidt, DI; University of California, Irvine; University of California, Irvine; University of California, Irvine; University of California, Irvine lmerlino@uci.edu

Animals that undergo seasonal changes in behavior present a robust opportunity to understand the mechanisms that mediate trade-offs between self-maintenance activities and reproduction. Here we utilize the seasonality of a northern population of red-sided garter snakes (Thamnophis sirtalis parietalis) in Manitoba, Canada to investigate these mechanisms. These garter snakes undergo winter dormancy for 8 months each year, emerge to a brief 4-week mating season in spring, and eventually migrate to summer feeding areas before returning to the hibernacula in fall. Critically, snakes do not eat during the mating season, even if presented with food. We previously showed that adrenal glucocorticoids mediate the seasonal transition from reproduction to migration and feeding behavior, but the mechanisms that facilitate these effects are unknown. Because endocannabinoids are known modulators of glucocorticoid signaling, we asked if cannabinoids are involved in mediating the effects of glucocorticoids on this seasonal switch. We used liquid chromatography with tandem mass spectrometry to measure endocannabinoids and paracannabinoids in the brains of courting (n = 5) and migrating (n = 3) male snakes. Although initial sample sizes are small, our preliminary data indicate that the endocannabinoid 2-arachidonoylglycerol (P = 0.08) and paracannabinoid oleoylethanolamide (P = 0.03) are lower in migrating snakes compared to courting males. It is exciting to note that oleoylethanolamide is a cannabinoid-like compound that inhibits feeding behavior in mammals. Thus, our results suggest that decreases in both cannabinoids and glucocorticoids interact within the brain to activate feeding behavior, thereby favoring self-maintenance activities over reproductive opportunities.