The thalamic intergeniculate leaflet mediates locomotor activity-induced reversal of phenotype in photoperiod nonresponsive Siberian hamsters
The thalamic intergeniculate leaflet mediates locomotor activity-induced reversal of phenotype in photoperiod nonresponsive Siberian hamsters
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DOI：
10.1177/0748730406287996
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发表时间：
2006-06-01
影响因子：
3.5
通讯作者：
Goldman, BD
中科院分区：
文献类型：
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作者：
Freeman, DA;Teubner, BJW;Goldman, BD
在实验室选择的光周期无反应（NR）西伯利亚仓鼠品系中检查了丘脑膝间小叶（IGL）在光周期反应中的作用。当暴露于短日照长度（例如，每天 10 小时的光照）时，NR 仓鼠无法表现出典型的冬季型反应（即性腺退化和冬季型毛皮的发育）。早期的研究表明，如果 NR 仓鼠可以自由使用跑轮，那么它们在暴露于短光周期时会表现出冬季型反应。本研究检验了这样的假设：这种运动活动诱导的表型逆转依赖于 IGL。雄性 NR 仓鼠在短日照时间被关在配有跑轮的笼子里之前，会先破坏 IGL。监测活动节律 8 周，之后获得皮毛反应和配对睾丸重量。与接受跑轮的假手术NR动物相比，IGL切除的动物夜间跑轮活动的持续时间没有增加，并且比假手术损伤的动物在夜间变得活跃。受损动物也未能表现出典型的短光周期诱导的性腺退化和皮毛蜕皮。结果表明 IGL 参与了跑轮活动影响光周期反应的机制。
The role of the intergeniculate leaflet of the thalamus (IGL) in photoperiod responsiveness was examined in a laboratory-selected line of photoperiod nonresponsive (NR) Siberian hamsters. NR hamsters fail to exhibit typical winter-type responses (i.e., gonadal regression and development of winter-type pelage) when exposed to short day lengths (e.g., 10 h of light/day). Earlier studies revealed that NR hamsters will exhibit winter-type responses when exposed to short photoperiod if they are given free access to a running wheel. The present study tested the hypothesis that this locomotor activity-induced reversal of phenotype is dependent on the IGL. Male NR hamsters underwent destruction of the IGL prior to being housed in short day lengths in cages equipped with running wheels. Activity rhythms were monitored for 8 weeks, after which time pelage response and paired testes weights were obtained. In contrast to sham-operated NR animals given access to running wheels, IGL-ablated animals showed no increase in the duration of nocturnal running wheel activity and became active later in the night than sham-lesioned animals. Lesioned animals also failed to exhibit the typical short photoperiod-induced gonadal regression and pelage molt. The results implicate the IGL in the mechanism by which running wheel activity can influence photoperiodic responses.