Meeting Abstract

P2.124  Tuesday, Jan. 5  Functional effects of endocannabinoid signaling on ingestive behavior in Siberian Hamsters SMITH, N.S.; ADAMS, S.A.*; HO, J.M.; DEMAS, G.E.; Xavier University of Louisiana; Indiana University nsmith8@xula.edu

Siberian hamsters are a seasonally breeding species that undergo seasonal changes in energy balance, losing ~30-40% of their body mass in short “winter-like” days. These changes are driven primarily by changes in food intake, but the underlying neuroendocrine mechanisms are still unknown. Hypothalamic peptides traditionally attributed to regulation of energy balance give little explanation for this seasonal change. Endocannabinoids (EC), specifically those acting at CB₁ receptors, have been linked to the regulation of ingestive behavior in other rodent species but their functional effects in Siberian hamsters have yet to be tested. To determine the functional effects of EC signaling we housed animals in long days or short days and injected them with either a CB₁ agonist (ACEA) or antagonist (SR141716) for five days and measured food intake and hoarding. We found that blockade of CB₁ receptors decreased food intake, but only in long-day animals. While drug treatment had no effect on hoarding, photoperiod differentially affected hoarding within each sex: long-day males hoarded more than short-day males whereas short-day females hoarded more than long-day females. Together these findings indicate patterns of hoarding across photoperiod differ between sexes, and that functional effects of EC signaling in Siberian hamsters leaves the possibility for a role in mediating seasonal changes in energy balance.