Oishi T, Mohri Y, Kaneko T, Sasaki M, Hattori A, Obara Y, Masuda A
Department of Biological Science, Faculty of Science, Nara Women's University, Japan.
J Pineal Res. 1996 Oct;21(3):149-54. doi: 10.1111/j.1600-079x.1996.tb00282.x.
Relation between retinal melatonin and corneal mitotic rhythms in the Japanese quail was investigated in experiments manipulating the ocular physiology by treatments with formoguanamine hydrochloride (FG) and eye-lid suture. In experiment 1, we investigated the effects of FG, which is known to induce photoreceptor degeneration, on retinal melatonin and corneal mitotic rhythms. FG-treatment completely abolished the retinal melatonin rhythms in both LD 12:12 and constant darkness (DD), but the corneal mitotic rhythm was maintained with high mitotic rate in darkness under a LD cycle and subjective night under DD. The result suggests that 1) the photoreceptor cells in the retina are the site for melatonin production and/or for the oscillator which drives the circadian rhythm in retinal melatonin, and 2) melatonin is not involved in generation of the corneal mitotic rhythm. In experiment 2, we investigated the effects of eye-lid suture, which is known to induce eye enlargement and bulgy cornea, on the retinal melatonin and corneal mitotic rhythms. Eye-lid suture abolished the corneal mitotic rhythm in both LD and DD, with a high mitotic rate being maintained throughout 24 hr. But retinal melatonin maintained its rhythm with high levels in darkness under a LD cycle and in subjective night under DD. The result suggests that 1) bulgy cornea in the sutured eye was induced by the increase in mitotic rate in the light period, and 2) disappearance of the corneal mitotic rhythm does not have a relation to retinal melatonin. These results suggest that retinal melatonin is not involved in generation of the corneal mitotic rhythm and that there are two circadian clock systems in the eye.
通过用盐酸甲脒胍（FG）处理和眼睑缝合来操纵眼部生理，在实验中研究了日本鹌鹑视网膜褪黑素与角膜有丝分裂节律之间的关系。在实验1中，我们研究了已知会诱导光感受器退化的FG对视网膜褪黑素和角膜有丝分裂节律的影响。FG处理在12:12的光暗周期（LD）和持续黑暗（DD）条件下均完全消除了视网膜褪黑素节律，但在LD周期的黑暗中以及DD条件下的主观夜间，角膜有丝分裂节律以高有丝分裂率得以维持。结果表明：1）视网膜中的光感受器细胞是褪黑素产生的部位和/或驱动视网膜褪黑素昼夜节律的振荡器所在部位；2）褪黑素不参与角膜有丝分裂节律的产生。在实验2中，我们研究了已知会导致眼球增大和角膜凸起的眼睑缝合对视网膜褪黑素和角膜有丝分裂节律的影响。眼睑缝合在LD和DD条件下均消除了角膜有丝分裂节律，在整个24小时内有丝分裂率一直保持较高水平。但视网膜褪黑素在LD周期的黑暗中以及DD条件下的主观夜间仍保持其节律且水平较高。结果表明：1）缝合眼中的角膜凸起是由光照期有丝分裂率增加引起的；2）角膜有丝分裂节律的消失与视网膜褪黑素无关。这些结果表明视网膜褪黑素不参与角膜有丝分裂节律的产生，并且眼睛中存在两个昼夜节律时钟系统。
