Department of Zoology, Stockholm University, Svante Arrhenius vag 18A, S-10691 Stockholm, Sweden.
Front Biosci (Landmark Ed). 2010 Jun 1;15(3):1040-74. doi: 10.2741/3661.
Circadian rhythms are known for locomotory and reproductive behaviours, and the functioning of sensory organs, nervous structures, metabolism and developmental processes. The mechanisms and cellular bases of control are mainly inferred from circadian phenomenologies, ablation experiments and pharmacological approaches. Cellular systems for regulation summarised here comprise the retina, the eyestalk neuroendocrine X-organ-sinus gland system, several neuropeptides such as red pigment concentrating, hyperglycaemic and pigment-dispersing hormones, and factors such as serotonin and melatonin. No master clock has been identified, but a model of distributed clockwork involves oscillators such as the retinular cells, neurosecretory systems in the optic lobes, putative brain pacemakers, and the caudal photoreceptor. Extraretinal brain photoreceptors mediate entrainment. Comparative analyses of clock neurons and proteins known from insects may allow the identification of candidate clock neurons in crustaceans as putative homologues in the two taxa. Evidence for the existence of "insect-like" intracellular clock proteins and (light sensitive) transcription factors is scarce, but clock-, period-, and cryptochrome-gene products have been localised in the CNS and other organs rendering further investigations into crustacean clockwork very promising.
昼夜节律控制着动物的运动和生殖行为，以及感觉器官、神经结构、代谢和发育过程的功能。控制的机制和细胞基础主要是从昼夜节律现象、消融实验和药理学方法中推断出来的。这里总结的调节细胞系统包括视网膜、眼柄神经内分泌 X 器官-窦腺系统、几种神经肽，如红色素浓缩激素、高血糖激素和色素分散激素，以及血清素和褪黑素等因素。虽然尚未确定主钟，但分布式时钟模型涉及视网膜细胞、视叶中的神经分泌系统、脑起搏器和尾状光感受器等振荡器。视网膜外的脑光感受器介导节律同步。对昆虫中已知的时钟神经元和蛋白质进行比较分析，可能有助于确定甲壳类动物中潜在的同源时钟神经元。虽然“类似昆虫”的细胞内时钟蛋白和（光敏感）转录因子的存在证据很少，但时钟、周期和隐色素基因产物已在中枢神经系统和其他器官中定位，这使得对甲壳类动物生物钟的进一步研究非常有前途。
