Photoperiod or the duration of daylight has been implicated as a risk factor in the development of mood disorders. The dopamine and serotonin systems are impacted by photoperiod and are consistently associated with affective disorders. Hence, we evaluated, at multiple stages of postnatal development, the expression of key dopaminergic (TH) and serotonergic (Tph2, SERT, and Pet-1) genes, and midbrain monoamine content in mice raised under control Equinox (LD 12:12), Short winter-like (LD 8:16), or Long summer-like (LD 16:8) photoperiods. Focusing in early adulthood, we evaluated the midbrain levels of these serotonergic genes, and also assayed these gene levels in the dorsal raphe nucleus (DRN) with RNAScope. Mice that developed under Short photoperiods demonstrated elevated midbrain TH expression levels, specifically during perinatal development compared to mice raised under Long photoperiods, and significantly decreased serotonin and dopamine content throughout the course of development. In adulthood, Long photoperiod mice demonstrated decreased midbrain Tph2 and SERT expression levels and reduced Tph2 levels in the DRN compared Short photoperiod mice. Thus, evaluating gene × environment interactions in the dopaminergic and serotonergic systems during multiple stages of development may lead to novel insights into the underlying mechanisms in the development of affective disorders.

光周期或日光持续时间被认为是情绪障碍发展的危险因素。多巴胺和血清素系统受到光周期的影响，并始终与情感障碍有关。因此，我们在出生后发育的多个阶段评估了关键多巴胺能 ( TH ) 和血清素 ( Tph2、SERT和Pet-1) 基因和中脑单胺含量在对照 Equinox (LD 12:12)、短冬样 (LD 8:16) 或长夏样 (LD 16:8) 光周期下饲养的小鼠。着眼于成年早期，我们评估了这些血清素基因的中脑水平，并使用 RNAScope 分析了中缝背核 (DRN) 中的这些基因水平。在短光周期下发育的小鼠表现出中脑TH表达水平升高，特别是在围产期发育期间，与长光周期下发育的小鼠相比，并且在整个发育过程中血清素和多巴胺含量显着降低。在成年期，长光周期小鼠表现出中脑Tph2和SERT表达水平降低和Tph2降低DRN 中的水平比较了短光周期小鼠。因此，在发育的多个阶段评估多巴胺能和血清素能系统中基因×环境的相互作用可能会导致对情感障碍发展的潜在机制的新见解。