Lockley S W, Skene D J, Thapan K, English J, Ribeiro D, Haimov I, Hampton S, Middleton B, von Schantz M, Arendt J
School of Biological Sciences, University of Surrey, Guildford, UK.
J Clin Endocrinol Metab. 1998 Sep;83(9):3369-72. doi: 10.1210/jcem.83.9.5244.
Light affects the circadian axis in at least two ways. It can cause the acute suppression of pineal melatonin synthesis, and/or a phase-shift of the circadian oscillator. As recent evidence has suggested that extraocular light exposure may cause phase-shifts of the circadian clock, we have investigated whether suppression of melatonin can be induced by the same type of light exposure. In the first study subjects' eyes were exposed to white light (2250 lux for 30 mins) via a fibre optic cable. As expected, suppression of nighttime plasma melatonin levels (61 +/- 6%) was observed. In the second study, light of the same quality but higher intensity (14,000 or 67,500 lux for 180 mins) was delivered in the same manner to the popliteal region behind the subjects' knees, whilst shielding their eyes. No suppression of plasma melatonin levels (4 +/- 7%) was detected in any of the subjects. Thus, extraocular photoreception, if it exists in mammals, does not affect the suprachiasmatic nucleipineal pathway.
光线至少通过两种方式影响昼夜节律轴。它可导致松果体褪黑素合成的急性抑制，和/或昼夜振荡器的相位偏移。由于最近的证据表明，眼外光暴露可能导致生物钟的相位偏移，我们研究了同类型的光暴露是否能诱导褪黑素的抑制。在第一项研究中，通过光纤电缆让受试者的眼睛暴露于白光下（2250勒克斯，持续30分钟）。正如预期的那样，观察到夜间血浆褪黑素水平受到抑制（61±6%）。在第二项研究中，以相同的方式将相同质量但强度更高的光（14000或67500勒克斯，持续180分钟）照射到受试者膝盖后方的腘窝区域，同时遮住他们的眼睛。在任何受试者中均未检测到血浆褪黑素水平受到抑制（4±7%）。因此，眼外光感受（如果在哺乳动物中存在的话）不会影响视交叉上核 - 松果体途径。
