| Project/Area Number |
09670998
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Psychiatric science
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| Research Institution | Oita Medical University |
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Principal Investigator |
NAGAYAMA Haruo Oita Medical University School of Medicine, Professor, 医学部, 教授 (70100899)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1998: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1997: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | CIRCANNUAL RHYTHM / 8-OH-DPAT / NEUROLEPTICS / HALOPERIDOL / SEROTONIN SYNDROME / HYPOTHERMIA / CIRCADIAN RHYTHM / セロトニンアゴニスト |
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| Research Abstract |
1) In order to elucidate whether circadian and circannual rhythms exist in the effect of 8-OH-DPAT,
8-OH-DPAT was administered subcutaneously to male Wistar rats at different hours of the day in different seasons, and the 5-HT syndrome was quantified by recording the total frequency of forepaw treading and head weaving for a total of 90 mm. Each rat was used only once. The experiments were repeated five time at three-month intervals.
2) Both forepaw treading and head weaving exhibited a significant circadian rhythm in every month examined.
3) Both forepaw treading and head weaving exhibited a significant annual rhythm at all time points tested. The phases of the circadian rhythm exhibit one year period variations while those of the annual rhythm exhibit one day period variations. The annual rhythm in the responsiveness to 8-OH-DPAT was confirmed in animals that were kept under constant environmental conditions of the same temperature and the same light-dark period through successive generations. Taking this into account, it is strongly suggested that this is not a phenomenon based on direct reaction to either the photoperiodicity or seasonal change in the environmental temperature, but this is an endogenous circannual rhythm.
4) The results suggest that both circadian and circannual rhythms exist in the responsiveness to the drug.
5) Next, the rhythm in the responsiveness to 8-OH-DPAT was examined by observing hypothermia, another index of the 5-HIIA receptor function. The parameters of assessing the hypothermic response displayed significant circadian and circannual rhythms.
6) Circannual rhythm in the effect of haloperidol is being examined by observing sedative effects in rats.
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