Analysis of ontogeny of circadian rhythm and the transmission of circadian-rhythm-information

我们研究了1)生物节律中心视交叉上核（SCN）昼夜节律的个体发生，以及2)昼夜节律信息从视交叉上核到其他脑区的传递。已知SCN中的时钟机制涉及转录负反馈回路，其中clock和BMAL1作为正调节因子，三期基因产物在负反馈中起作用。1)为了阐明母性对昼夜节律个体发生的影响，我们测量了明暗（LD）周期和反向LD （DL）周期(1)从出生之日起和出生后6天)和持续昏暗（DD）喂养的视力大鼠幼鼠SCN中rPer2、rBmla1和arg- vasressin （SCN输出信号递质）mrna的昼夜节律。采用RT-PCR检测m - rna，并在每个样品中采用β -actin mRNA归一化。rPer2、rBmal1和rAVP mRNA的节律性在LD携带的情况下，在护理期间更自由地运行。2周龄时，环境光照周期与坝体配合，引导幼犬的节奏。PER2激活rBmal1转录可能在时钟机制成熟后才起作用。结果表明，哺乳坝在一定程度上影响了幼犬的昼夜节律。2)为了了解SCN到松果体的昼夜信号转导系统，我们采用1)中的PT PER测定了褪黑激素注射对打孔大鼠SCN、PVN和松果体中rPer2和AVP mrna （1 mg/kg, i.p）的影响。同时测定SCN和PVN中AVP肽的含量。PVN。在SCN中，rPer2的含量在光照和暗期均有所增加，而AVP mRNA的含量未见波动。在PVN中，rPer2在光照期和暗期分别降低和升高。在松果体中，褪黑激素注射后，rPer2 mRNA在60时升高。最近，褪黑激素- avp相互作用系统。结果可能表明PVN与SCN时钟活动在时间上是耦合的。我们至少在一定程度上阐明了视交叉上核昼夜节律的发展以及SCN的输出机制。少

We investigated 1)ontogeny of the circadian rhythm in the suprachiasmatic nucleus (SCN), a center of biological rhythm, and 2)transmission of circadian-rhythm-information from the SCN to the other brain area. A clock mechanism in the SCN known to involve a transcriptional negative feedback loop in which CLOCK and BMAL1 function as positive regulators and three period gene products play a role in negative feedback. 1)To clarify the maternal effects on the ontogeny of circadian rhythm, we measured the circadian rhythm of rPer2, rBmla1 and rAVP (arg-vasopressin, an output signal transmitter from the SCN) mRNAs in the SCN of sighted rat-pups nursed under the light-dark (LD) cycle and nursed under the reversed LD (DL) cycle (two groups) which were i) nursed from the day of birth and ii) 6 days after birth) or under the constant dim light (DD), and kept. The m RNAs were determined using RT-PCR and normalized by beta-actin mRNA in each sample. The rPer2, rBmal1 and rAVP mRNA rhythmicity were … More free run during the nursing period even under the LD entrained condition. At the 2nd week of age, environmental lighting cycle with the dam co-operate to entrain the pup's rhythm. The rBmal1 transcriptional activation by PER2 might be functioning after the maturation of clock mechanisms. The results indicate that the nursing dam partially entrains pup's circadian rhythm. 2)To know the transduction system of circadian signals from the SCN to the pineal gland, we determined the effects of melatonin injection on (1 mg/kg, i.p.) rPer2 and AVP mRNAs in the punched out SCN, PVN and pineal gland of rats by using PT PER as in 1). AVP peptide contents were also measured in SCN and PVN. PVN. In the SCN, rPer2 content increased at both light and dark period, however no fluctuations were shown in the AVP mRNA. In the PVN, rPer2 decreased and increased at light and dark period, respectively. In the pineal gland, rPer2 mRNA increased at 60 after the melatonin injection. Recently, the melatonin-AVP reciprocal systems. The results might indicate that PVN is temporally coupled with the SCN clock activity.We clarified the development of circadian rhythm in the suprachiasmatic nucleus and the output mechanisms from the SCN, at least in part. Less