COMPARISON OF VISUAL SENSITIVITY FOR SUPPRESSION OF PINEAL MELATONIN AND CIRCADIAN PHASE-SHIFTING IN THE GOLDEN-HAMSTER
COMPARISON OF VISUAL SENSITIVITY FOR SUPPRESSION OF PINEAL MELATONIN AND CIRCADIAN PHASE-SHIFTING IN THE GOLDEN-HAMSTER
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DOI：
10.1016/0006-8993(91)90200-f
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发表时间：
1991-07-19
期刊：
影响因子：
2.9
通讯作者：
TAKAHASHI, JS
中科院分区：
文献类型：
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作者：
NELSON, DE;TAKAHASHI, JS
在金黄仓鼠中，使用在恒定黑暗中的单色光（503 nm）的300 s刺激来测量松果体褪黑激素的光抑制的视觉灵敏度。 增加刺激辐照度引起的松果体褪黑激素含量的单调下降。 大于3.5 × 10（10）光子cm-2.s-1的辐照度导致仓鼠松果体中褪黑激素的显著减少。 在10（11）光子cm-2.s-1以上出现响应饱和，褪黑激素水平被抑制至未受刺激动物中测量水平的约7%。 使用4参数Naka-Rushton函数拟合数据，抑制松果体褪黑激素的半饱和常数为1.3 x 10（10）光子cm-2.s-1。 还使用相同的刺激参数在仓鼠中测量了昼夜节律的光诱导途径的灵敏度。 光抑制的松果体褪黑激素是25倍（1.4个对数单位）更敏感的辐射比相移响应测量的昼夜节律的转轮活动（比较两个响应的半饱和常数）。 然而，这两种反应对光线的敏感度都远远低于在金黄仓鼠中通过行为测量的其他视觉反应。
Visual sensitivity for light suppression of pineal melatonin was measured in golden hamsters using 300 s stimuli of monochromatic light (503 nm) in constant darkness. Increasing stimulus irradiance caused a monotonic decrease in pineal-melatonin content. Irradiance greater than 3.5 x 10(10) photons cm-2.s-1 caused significant reductions of melatonin in the hamster pineal. Saturation of the response occurred above 10(11) photons cm-2.s-1 and melatonin levels were suppressed to approximately 7% of levels measured in unstimulated animals. Using a 4-parameter Naka-Rushton function to fit the data, the half-saturation constant for suppression of pineal melatonin was 1.3 x 10(10) photons cm-2.s-1. The sensitivity of the photic-entrainment pathway for circadian rhythms has also been measured in the hamster using identical stimulus parameters. Light suppression of pineal melatonin was 25 times (1.4 log units) more sensitive to irradiance than the phase-shifting response measured for the circadian rhythm of running-wheel activity (comparing the half-saturation constants for the two responses). Both of these responses, however, are much less sensitive to light than other visual responses measured behaviorally in the golden hamster.