CIRCADIAN CLOCK IN XENOPUS EYE CONTROLLING RETINAL SEROTONIN N-ACETYLTRANSFERASE
CIRCADIAN CLOCK IN XENOPUS EYE CONTROLLING RETINAL SEROTONIN N-ACETYLTRANSFERASE
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DOI：
10.1038/305133a0
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发表时间：
1983-01-01
期刊：
影响因子：
64.8
通讯作者：
IUVONE, PM
中科院分区：
文献类型：
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作者：
BESHARSE, JC;IUVONE, PM
昼夜节律由内源性振荡器或时钟控制。这些时钟在恒定条件下表现出大约24小时的持续周期，与外部环境中的周期性线索（授时因子）具有特定的相位关系，并且由于时钟的相位可能随着授时因子的相位变化而改变，因此具有可塑性。尽管许多过程表现出昼夜节律性，但内源性时钟的性质和位置仍然不明确。最近脊椎动物的证据表明，哺乳动物视交叉上核和鸟类松果体中含有影响吲哚胺代谢节律性的时钟。脊椎动物视网膜也表现出血清素-乙酰转移酶活性（NAT, EC 2.1.1.4） 3-5的昼夜节律，这是一种控制褪黑激素合成的关键酶，和光感受器盘脱落6,7。后一个过程可能受褪黑素的调节，而直接的细胞事件似乎是由眼睛局部控制的。虽然没有证明持续的振荡和携带，但有数据表明，眼生物钟影响了眼盘脱落。我们通过研究培养的异种眼杯的视网膜NAT活性来寻找生物钟的证据，并在这里报告了它们的体外系统的持续振荡和携带。这些数据表明，除了视交叉上核和松果体外，眼睛本身必须被视为脊椎动物生物钟的所在地。
Circadian rhythms are controlled by endogenous oscillators or clocks. These clocks exhibit a persistent period of approximately 24 h in constant conditions, a specific phase relationship to a periodic cue (zeitgeber) in the external environment, and plasticity in that the phase of the clock may be altered in response to a phase change in the zeitgeber1. Although many processes exhibit circadian rhythmicity, the nature and location of endogenous clocks remain poorly defined. Recent evidence in vertebrates suggests that the mammalian suprachiasmatic nucleus and the avian pineal gland contain clocks that affect the rhythmicity of indoleamine metabolism2. The vertebrate retina also exhibits a circadian rhythm of serotoninN-acetytransferase activity (NAT, EC 2.1.1.4)3–5, a key enzyme controlling melatonin synthesis, and of photoreceptor disk shedding6,7. The latter process may be regulated by melatonin8, and the immediate cellular events seem to be controlled locally within the eye9–11. Although sustained oscillation and entrainment were not demonstrated, data suggesting that an ocular circadian clock influences disk shedding have been reported9. We sought evidence for an ocular clock by studying retinal NAT activity inXenopuseye cups maintained in culture and report here both sustained oscillation and entrainment of thein vitrosystem. The data indicate that in addition to the suprachiasmatic nucleus and pineal gland, the eye itself must be regarded as the locus of a circadian clock in vertebrates.