Abstract：
This study aimed to investigate the behavioral responses and circadian rhythms of mice to both rapid and gradual increases in photoperiod, mimicking the transition from winter to summer, which is associated with a heightened prevalence of hospitalizations for mania and suicidal behavior. Behavioral tests were performed in C57BL/6 male mice exposed to a transitional photoperiod, from short to long durations. To determine if circadian rhythms are affected, we measured spontaneous locomotor activity and body temperature. Mice exhibited heightened exploratory and risk-taking behaviors compared with equatorial and static long (16:8 h of light-dark cycle for several days) groups. These behaviors were prevented by lithium. Spontaneous locomotor activity and body temperature rhythms persisted and were effectively synchronized; however, the relative amplitude of activity and interdaily stability were diminished. Additionally, the animals displayed increased activity during the light phase. Photoperiodic transition modulates behavior and circadian rhythms, mirroring certain features observed in bipolar disorder patients. This study introduces an animal model for investigating mania-like behavior induced by photoperiodic changes, offering potential insights for suicide prevention strategies and the management of mood disorders.
摘要：
这项研究旨在研究小鼠对光周期快速和逐渐增加的行为反应和昼夜节律，模仿从冬天到夏天的过渡，这与躁狂症和自杀行为的住院率升高有关。在暴露于过渡光周期的C57BL/6雄性小鼠中进行行为测试，从短期到长期。为了确定昼夜节律是否受到影响，我们测量了自发的运动活动和体温。与赤道和静态长（16：8小时的明暗周期持续几天）组相比，小鼠表现出更高的探索和冒险行为。这些行为被锂阻止。自发的运动活动和体温节律持续存在并有效地同步；然而，活动的相对幅度和每日稳定性均降低。此外,动物在光照阶段活动增加。光周期跃迁调节行为和昼夜节律，反映了在双相情感障碍患者中观察到的某些特征。这项研究介绍了一种动物模型，用于研究由光周期变化引起的躁狂症样行为，为自杀预防策略和情绪障碍的管理提供潜在的见解。
