2003 Fiscal Year Final Research Report Summary
Analysis of ontogeny of circadian rhythm and the transmission of circadian-rhythm-information
| Project/Area Number |
14570063
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Environmental physiology (including Physical medicine and Nutritional physiology)
|
|---|
| Research Institution | Nagoya City University |
|---|
Principal Investigator |
ISOBE Yoshiaki Nagoya City University, Graduate School of Medical Sciences, Research Associate, 大学院・医学研究科, 助手 (70094357)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
INOUYE Shin-ishi Yamaguchi University, Graduate School of Scinces, Professor and Chair, 大学院・理学研究科, 教授 (10274151)
|
|---|
| Project Period (FY) |
2002 – 2003
|
| Keywords | Circadian rhythm / Clock controlled gene / Per / Bmal1 / vasopressin / Melatonin / suprachiasmatic nucleus / Pineal gland |
|---|
| Research Abstract |
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
|
Research Products
(2 results)
