Harrington M E, Rusak B
Department of Psychology, Dalhousie University, Halifax, Nova Scotia, Canada.
Physiol Behav. 1988;42(2):183-9. doi: 10.1016/0031-9384(88)90296-x.
Retino-recipient cells in the hamster lateral geniculate nucleus project to the suprachiasmatic nucleus via the geniculo-hypothalamic tract (GHT). GHT-ablation alters phase advance shifts to light pulses in a hamster's late subjective night. In this study, the effects of GHT-ablation on wheel-running rhythms of hamsters housed under continuous illumination (LL) were assessed. In the first experiment, hamsters received GHT-ablation or sham surgery while under a light:dark schedule and were subsequently exposed to 250 days of LL. GHT-ablated hamsters showed rhythms with shorter periods and were less likely to show split activity rhythms than sham-operated or partial-lesion controls. In the second experiment, hamsters were housed under LL until rhythms split into two components; hamsters then received either GHT-ablation or sham surgery. Four of seven GHT-ablated hamsters showed re-fusion of their activity pattern into one component, while none of the eight sham-operated animals showed such re-fusion. The results of these two experiments indicate that GHT-ablation alters the responsiveness of the activity rhythm pacemaker to LL exposure.
仓鼠外侧膝状核中的视网膜接受细胞通过膝状体下丘脑束（GHT）投射到视交叉上核。GHT切除会改变仓鼠主观夜后期对光脉冲的相位提前偏移。在本研究中，评估了GHT切除对持续光照（LL）饲养的仓鼠转轮节律的影响。在第一个实验中，仓鼠在明暗周期下接受GHT切除或假手术，随后暴露于250天的LL环境中。与假手术或部分损伤对照组相比，GHT切除的仓鼠表现出周期更短的节律，且不太可能出现分裂活动节律。在第二个实验中，仓鼠在LL环境中饲养，直到节律分裂为两个成分；然后仓鼠接受GHT切除或假手术。七只GHT切除的仓鼠中有四只的活动模式重新融合为一个成分，而八只假手术动物中没有一只表现出这种重新融合。这两个实验的结果表明，GHT切除会改变活动节律起搏器对LL暴露的反应性。
