鸟类褪黑素合成：鸡松果体和视网膜中血清素N - 乙酰转移酶mRNA的光调节和昼夜节律调节

Avian melatonin synthesis: photic and circadian regulation of serotonin N-acetyltransferase mRNA in the chicken pineal gland and retina.

作者信息

Bernard M, Iuvone P M, Cassone V M, Roseboom P H, Coon S L, Klein D C

机构信息

Section on Neuroendocrinology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.

出版信息

J Neurochem. 1997 Jan;68(1):213-24. doi: 10.1046/j.1471-4159.1997.68010213.x.

DOI:10.1046/j.1471-4159.1997.68010213.x

PMID:8978728

Abstract

The circadian rhythms in melatonin production in the chicken pineal gland and retina reflect changes in the activity of serotonin N-acetyltransferase (arylalkylamine N-acetyltransferase; AA-NAT; EC 2.3.1.87). Here we determined that the chicken AA-NAT mRNA is detectable in follicular pineal cells and retinal photoreceptors and that it exhibits a circadian rhythm, with peak levels at night. AA-NAT mRNA was not detected in other tissues. The AA-NAT mRNA rhythm in the pineal gland and retina persists in constant darkness (DD) and constant lighting (LL). The amplitude of the pineal mRNA rhythm is not decreased in LL. Light appears to influence the phase of the clock driving the rhythm in pineal AA-NAT mRNA in two ways: The peak is delayed by approximately 6 h in LL, and it is advanced by > 4 h by a 6-h light pulse late in subjective night in DD. Nocturnal AA-NAT mRNA levels do not change during a 20-min exposure to light, whereas this treatment dramatically decreases AA-NAT activity. These observations suggest that the rhythmic changes in chicken pineal AA-NAT activity reflect, at least in part, clock-generated changes in mRNA levels. In contrast, changes in mRNA content are not involved in the rapid light-induced decrease in AA-NAT activity.

摘要

鸡松果体和视网膜中褪黑素分泌的昼夜节律反映了血清素N - 乙酰基转移酶（芳基烷基胺N - 乙酰基转移酶；AA - NAT；EC 2.3.1.87）活性的变化。在此我们确定，鸡AA - NAT mRNA在卵泡松果体细胞和视网膜光感受器中可检测到，并且呈现昼夜节律，在夜间达到峰值水平。在其他组织中未检测到AA - NAT mRNA。松果体和视网膜中的AA - NAT mRNA节律在持续黑暗（DD）和持续光照（LL）条件下持续存在。在LL条件下，松果体mRNA节律的振幅并未降低。光似乎以两种方式影响驱动松果体AA - NAT mRNA节律的生物钟相位：在LL条件下，峰值延迟约6小时，而在DD条件下主观夜间后期给予6小时光脉冲可使峰值提前超过4小时。在20分钟的光照暴露期间，夜间AA - NAT mRNA水平没有变化，而这种处理会显著降低AA - NAT活性。这些观察结果表明，鸡松果体AA - NAT活性的节律性变化至少部分反映了生物钟产生的mRNA水平变化。相比之下，mRNA含量的变化与光诱导的AA - NAT活性快速下降无关。