1992 Fiscal Year Final Research Report Summary
Molecular basis of the circadian rhythm for peptides mRNA
| Project/Area Number |
02807016
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
環境生理学(含体力医学･栄養生理学)
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| Research Institution | Nagoya City University |
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Principal Investigator |
ISOBE Yoshiaki Nagoya City Univ.Med.Sch. Assistant, 医学部, 助手 (70094357)
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| Co-Investigator(Kenkyū-buntansha) |
INOUYE Shin-ichi Mitsubishikasei Inst. Life Sci. Chief Researcher, 主任研究員
NISHINO Hitoo Nagoya City Univ.Med.Sch. Professor, 医学部, 教授 (60073730)
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| Project Period (FY) |
1990 – 1992
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| Keywords | Circadian rhythm / Vasoactive intestinal peptide / Vasopressin / Development / Gastrin releasing peptide / Culture / Intracellular Ca |
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| Research Abstract |
In mammals, a pacemaker of circadian rhythms is considered to be located in the suprachiasmatic nuclei(SCN). We examined the role of peptides contained in the SCN of rats for molecular bases. Vasoactive intestinal peptide (VIP) and gastrin releasing peptide are colocalized in ventrolateral area of the SCN were measured by ELA method under the light dark cycle. No clear circadian rhythm of VIP and GRP was not observed in the 2-days-blind rats, though the VIP and GRP in intact rats showed higher concentration during the subjective night and day, respectively. The Northern analysis of mRNA was done to know the transcriptional stage in the synthesis of these peptides The SCN of 4-6 brains were microdissected every 4hr throughout a day and total RNA was extracted by the phenol-chloroform method. VIP mRNA levels showed higher during the dark than in the light period. This rhythmicity was not observed in the cortex. The results suggest possible involvement of neuropeptides in circadian genera
… More
tion at their messenger RNA levels.
Beside, to know the ontogeny of these peptides oscillation for circadian clock, the development of these peptides were analyzed. The concentration of VIP during the dark time began to higher in the dark period than in light one from the post natal day 4 and succeeded till the wean.
To establish an in vitro system to observe the SCN function for a long duration, we used a dissociated cell culture system to study the cellular mechanisms of SCN. Dispersed cells of SCN were obtained from P-1 day pups whose mother were kept under light-dark cycle. Arginine-vasopressin (AVP), plays important role for the output signal form the SCN in vivo, in the culture medium were measured. The release of AVP from these cells showed a accurate circadian oscillation. The circadian rhythms of AVP were reversed in phase when the cell were prepared 12hr out of phase from the pups kept under the light-dark cycle. Some neurons were certified by AVP antibody using the ABC method. The dispersed culture system provides a useful model for elucidating the mechanism of pacemaker. We, now, are developing the Organotipic slice culture having a number of advantage of structural organization. Less
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Research Products
(4 results)
