Extended exposure to continuous low intensity light abolishes the photosensitivity of retinal dopamine neurons.
Extended exposure to continuous low intensity light abolishes the photosensitivity of retinal dopamine neurons.
复制标题
长时间暴露在连续低强度光下会消除视网膜多巴胺神经元的光敏感性。
DOI：
10.1016/0024-3205(83)90825-1
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发表时间：
1983
期刊：
影响因子：
6.1
通讯作者：
Kamp,CW
中科院分区：
文献类型：
--
作者：
Morgan,WW;Kamp,CW
将雄性Sprague-Dawley大鼠分为2组。一组（实验组）在连续低强度光下饲养6个月，而另一组（对照组）在整个时间内暴露于标准的14小时光照：10小时黑暗循环光照条件。对于对照组和实验组，光强度为350-700勒克斯。6个月后，实验大鼠恢复循环照明。在1周和2个月时，在光/暗测试箱中测试所有大鼠的光厌恶行为。实验组大鼠只有58%的时间选择盒子的黑暗面，而对照组动物有79%的时间选择黑暗面。由于大鼠通常是夜行性的，避免光线，这些结果表明，实验大鼠可能永久性地失去了检测光线的功能的重要部分。第二次行为测试后，所有大鼠暗适应，15小时后，短期（30或60分钟）暴露于光对DA营业额的影响，从每只大鼠的一个视网膜进行了评估。将每只大鼠的另一个视网膜固定并进行组织学检查。光照可显著增强α-甲基-p-酪氨酸引起的对照组大鼠视网膜DA含量的下降，但对实验动物无类似作用。实验组大鼠视网膜DA含量明显减少。组织学检查表明，实验视网膜的外核层比连续光照4个月的大鼠受损更严重，但仍含有少数固缩的感光细胞核和几乎正常的内神经层。这些结果表明，延长暴露于光最终废除光厌恶行为，在这个时候也有一个多巴胺能无长突神经元的光敏性损失。
Male Sprague-Dawley rats were divided into 2 groups. One group (experimental) was housed for 6 months in continuous low intensity light while the other (control) was exposed to standard 14 hr light: 10 hr dark cyclic lighting conditions for the entire time. For both the control and experimental groups the light intensity was 350–700 Lux. After 6 months, the experimental rats were returned to cyclic lighting. At one week and again at 2 months the light aversion behavior of all rats was tested in a light/dark test box. The experimental rats chose the dark side of the box only 58% of the time while control animals preferred the dark 79% of the time. Since rats normally are nocturnal and avoid light, these results suggest that the experimental rats may have permanently lost a functionally significant portion of the ability to detect light. After the second behavioral test all rats were dark adapted and 15 hr later the effect of short term (30 or 60 min) exposure to light on DA turnover in one retina from each rat was assessed. The other retina from each rat was fixed and examined histologically. Light significantly enhanced the α methyl-p-tyrosine induced decline of DA in the retinas of the control rats but exerted no similar effect in the experimental animals. The retinal DA contents of the experimental rats were substantially depleted. Histological examination suggested that the outer nuclear layers of the experimental retinas were more severly damaged than those from rats exposed to continuous light for 4 months but still contained a few pycnotic photoreceptor nuclei and nearly normal looking inner neural layers. These results indicate that extended exposure to light eventually abolishes light aversion behavior and at this time there is also a loss of the photosensitivity of the dopaminergic amacrine neurons.