Depression-Like Responses Induced by Daytime Light Deficiency in the Diurnal Grass Rat (Arvicanthis niloticus)

摘要: Seasonal Affective Disorder (SAD) is one of the most common mood disorders with depressive symptoms recurring in winter when there less sunlight. The fact that light salient factor entraining circadian rhythms leads to phase-shifting hypothesis, which suggests episodes SAD are caused by misalignments between and habitual sleep times. However, how changes environmental lighting conditions lead fluctuations largely unknown. objective this study develop an animal model for some features/symptoms using diurnal grass rats Arvichantis niloticus explore neural mechanisms underlying associated changes. Animals were housed either a 12∶12 hr bright light∶dark (1000lux, BLD) or dim (50lux, DLD) condition. depression-like behaviors assessed sweet-taste Saccharin solution preference (SSP) forced swimming test (FST). DLD group showed higher levels compared those BLD. anxiety-like open field light/dark box test, however no significant differences observed two groups. involvement system on was investigated as well. Analysis locomotor activity revealed major daily could possibly contribute behaviors. To substrates behaviors, brain tissues from these animals analyzed immunocytochemistry. Attenuated indices 5-HT signaling BLD group. results lay groundwork establishing novel experimental paradigm SAD. also provide insights into light-dependent